tr///; simplify $utf8 =~ tr/nonutf8/nonutf8/

[perl5.git] / lib / B / Deparse.pm

# B::Deparse.pm
# Copyright (c) 1998-2000, 2002, 2003, 2004, 2005, 2006 Stephen McCamant.
# All rights reserved.
# This module is free software; you can redistribute and/or modify
# it under the same terms as Perl itself.

# This is based on the module of the same name by Malcolm Beattie,
# but essentially none of his code remains.

package B::Deparse;
use Carp;
use B qw(class main_root main_start main_cv svref_2object opnumber perlstring
         OPf_WANT OPf_WANT_VOID OPf_WANT_SCALAR OPf_WANT_LIST
         OPf_KIDS OPf_REF OPf_STACKED OPf_SPECIAL OPf_MOD OPf_PARENS
         OPpLVAL_INTRO OPpOUR_INTRO OPpENTERSUB_AMPER OPpSLICE OPpKVSLICE
         OPpCONST_BARE
         OPpTRANS_SQUASH OPpTRANS_DELETE OPpTRANS_COMPLEMENT OPpTARGET_MY
         OPpEXISTS_SUB OPpSORT_NUMERIC OPpSORT_INTEGER OPpREPEAT_DOLIST
         OPpSORT_REVERSE OPpMULTIDEREF_EXISTS OPpMULTIDEREF_DELETE
         OPpSPLIT_ASSIGN OPpSPLIT_LEX
         OPpPADHV_ISKEYS OPpRV2HV_ISKEYS
         OPpCONCAT_NESTED
         OPpMULTICONCAT_APPEND OPpMULTICONCAT_STRINGIFY OPpMULTICONCAT_FAKE
         OPpTRUEBOOL OPpINDEX_BOOLNEG
         SVf_IOK SVf_NOK SVf_ROK SVf_POK SVpad_OUR SVf_FAKE SVs_RMG SVs_SMG
         SVs_PADTMP SVpad_TYPED
         CVf_METHOD CVf_LVALUE
         PMf_KEEP PMf_GLOBAL PMf_CONTINUE PMf_EVAL PMf_ONCE
         PMf_MULTILINE PMf_SINGLELINE PMf_FOLD PMf_EXTENDED PMf_EXTENDED_MORE
         PADNAMEt_OUTER
        MDEREF_reload
        MDEREF_AV_pop_rv2av_aelem
        MDEREF_AV_gvsv_vivify_rv2av_aelem
        MDEREF_AV_padsv_vivify_rv2av_aelem
        MDEREF_AV_vivify_rv2av_aelem
        MDEREF_AV_padav_aelem
        MDEREF_AV_gvav_aelem
        MDEREF_HV_pop_rv2hv_helem
        MDEREF_HV_gvsv_vivify_rv2hv_helem
        MDEREF_HV_padsv_vivify_rv2hv_helem
        MDEREF_HV_vivify_rv2hv_helem
        MDEREF_HV_padhv_helem
        MDEREF_HV_gvhv_helem
        MDEREF_ACTION_MASK
        MDEREF_INDEX_none
        MDEREF_INDEX_const
        MDEREF_INDEX_padsv
        MDEREF_INDEX_gvsv
        MDEREF_INDEX_MASK
        MDEREF_FLAG_last
        MDEREF_MASK
        MDEREF_SHIFT
    );

$VERSION = '1.47';
use strict;
our $AUTOLOAD;
use warnings ();
require feature;

use Config;

BEGIN {
    # List version-specific constants here.
    # Easiest way to keep this code portable between version looks to
    # be to fake up a dummy constant that will never actually be true.
    foreach (qw(OPpSORT_INPLACE OPpSORT_DESCEND OPpITER_REVERSED OPpCONST_NOVER
                OPpPAD_STATE PMf_SKIPWHITE RXf_SKIPWHITE
                PMf_CHARSET PMf_KEEPCOPY PMf_NOCAPTURE CVf_ANONCONST
                CVf_LOCKED OPpREVERSE_INPLACE OPpSUBSTR_REPL_FIRST
                PMf_NONDESTRUCT OPpCONST_ARYBASE OPpEVAL_BYTES
                OPpLVREF_TYPE OPpLVREF_SV OPpLVREF_AV OPpLVREF_HV
                OPpLVREF_CV OPpLVREF_ELEM SVpad_STATE)) {
        eval { B->import($_) };
        no strict 'refs';
        *{$_} = sub () {0} unless *{$_}{CODE};
    }
}

# Todo:
#  (See also BUGS section at the end of this file)
#
# - finish tr/// changes
# - add option for even more parens (generalize \&foo change)
# - left/right context
# - copy comments (look at real text with $^P?)
# - avoid semis in one-statement blocks
# - associativity of &&=, ||=, ?:
# - ',' => '=>' (auto-unquote?)
# - break long lines ("\r" as discretionary break?)
# - configurable syntax highlighting: ANSI color, HTML, TeX, etc.
# - more style options: brace style, hex vs. octal, quotes, ...
# - print big ints as hex/octal instead of decimal (heuristic?)
# - handle 'my $x if 0'?
# - version using op_next instead of op_first/sibling?
# - avoid string copies (pass arrays, one big join?)
# - here-docs?

# Current test.deparse failures
# comp/hints 6 - location of BEGIN blocks wrt. block openings
# run/switchI 1 - missing -I switches entirely
#    perl -Ifoo -e 'print @INC'
# op/caller 2 - warning mask propagates backwards before warnings::register
#    'use warnings; BEGIN {${^WARNING_BITS} eq "U"x12;} use warnings::register'
# op/getpid 2 - can't assign to shared my() declaration (threads only)
#    'my $x : shared = 5'
# op/override 7 - parens on overridden require change v-string interpretation
#    'BEGIN{*CORE::GLOBAL::require=sub {}} require v5.6'
#    c.f. 'BEGIN { *f = sub {0} }; f 2'
# op/pat 774 - losing Unicode-ness of Latin1-only strings
#    'use charnames ":short"; $x="\N{latin:a with acute}"'
# op/recurse 12 - missing parens on recursive call makes it look like method
#    'sub f { f($x) }'
# op/subst 90 - inconsistent handling of utf8 under "use utf8"
# op/taint 29 - "use re 'taint'" deparsed in the wrong place wrt. block open
# op/tiehandle compile - "use strict" deparsed in the wrong place
# uni/tr_ several
# ext/B/t/xref 11 - line numbers when we add newlines to one-line subs
# ext/Data/Dumper/t/dumper compile
# ext/DB_file/several
# ext/Encode/several
# ext/Ernno/Errno warnings
# ext/IO/lib/IO/t/io_sel 23
# ext/PerlIO/t/encoding compile
# ext/POSIX/t/posix 6
# ext/Socket/Socket 8
# ext/Storable/t/croak compile
# lib/Attribute/Handlers/t/multi compile
# lib/bignum/ several
# lib/charnames 35
# lib/constant 32
# lib/English 40
# lib/ExtUtils/t/bytes 4
# lib/File/DosGlob compile
# lib/Filter/Simple/t/data 1
# lib/Math/BigInt/t/constant 1
# lib/Net/t/config Deparse-warning
# lib/overload compile
# lib/Switch/ several
# lib/Symbol 4
# lib/Test/Simple several
# lib/Term/Complete
# lib/Tie/File/t/29_downcopy 5
# lib/vars 22

# Object fields:
#
# in_coderef2text:
# True when deparsing via $deparse->coderef2text; false when deparsing the
# main program.
#
# avoid_local:
# (local($a), local($b)) and local($a, $b) have the same internal
# representation but the short form looks better. We notice we can
# use a large-scale local when checking the list, but need to prevent
# individual locals too. This hash holds the addresses of OPs that
# have already had their local-ness accounted for. The same thing
# is done with my().
#
# curcv:
# CV for current sub (or main program) being deparsed
#
# curcvlex:
# Cached hash of lexical variables for curcv: keys are
# names prefixed with "m" or "o" (representing my/our), and
# each value is an array with two elements indicating the cop_seq
# of scopes in which a var of that name is valid and a third ele-
# ment referencing the pad name.
#
# curcop:
# COP for statement being deparsed
#
# curstash:
# name of the current package for deparsed code
#
# subs_todo:
# array of [cop_seq, CV, is_format?, name] for subs and formats we still
# want to deparse.  The fourth element is a pad name thingy for lexical
# subs or a string for special blocks.  For other subs, it is undef.  For
# lexical subs, CV may be undef, indicating a stub declaration.
#
# protos_todo:
# as above, but [name, prototype] for subs that never got a GV
#
# subs_done, forms_done:
# keys are addresses of GVs for subs and formats we've already
# deparsed (or at least put into subs_todo)
#
# subs_declared
# keys are names of subs for which we've printed declarations.
# That means we can omit parentheses from the arguments. It also means we
# need to put CORE:: on core functions of the same name.
#
# in_subst_repl
# True when deparsing the replacement part of a substitution.
#
# in_refgen
# True when deparsing the argument to \.
#
# parens: -p
# linenums: -l
# unquote: -q
# cuddle: ' ' or '\n', depending on -sC
# indent_size: -si
# use_tabs: -sT
# ex_const: -sv

# A little explanation of how precedence contexts and associativity
# work:
#
# deparse() calls each per-op subroutine with an argument $cx (short
# for context, but not the same as the cx* in the perl core), which is
# a number describing the op's parents in terms of precedence, whether
# they're inside an expression or at statement level, etc.  (see
# chart below). When ops with children call deparse on them, they pass
# along their precedence. Fractional values are used to implement
# associativity ('($x + $y) + $z' => '$x + $y + $y') and related
# parentheses hacks. The major disadvantage of this scheme is that
# it doesn't know about right sides and left sides, so say if you
# assign a listop to a variable, it can't tell it's allowed to leave
# the parens off the listop.

# Precedences:
# 26             [TODO] inside interpolation context ("")
# 25 left        terms and list operators (leftward)
# 24 left        ->
# 23 nonassoc    ++ --
# 22 right       **
# 21 right       ! ~ \ and unary + and -
# 20 left        =~ !~
# 19 left        * / % x
# 18 left        + - .
# 17 left        << >>
# 16 nonassoc    named unary operators
# 15 nonassoc    < > <= >= lt gt le ge
# 14 nonassoc    == != <=> eq ne cmp
# 13 left        &
# 12 left        | ^
# 11 left        &&
# 10 left        ||
#  9 nonassoc    ..  ...
#  8 right       ?:
#  7 right       = += -= *= etc.
#  6 left        , =>
#  5 nonassoc    list operators (rightward)
#  4 right       not
#  3 left        and
#  2 left        or xor
#  1             statement modifiers
#  0.5           statements, but still print scopes as do { ... }
#  0             statement level
# -1             format body

# Nonprinting characters with special meaning:
# \cS - steal parens (see maybe_parens_unop)
# \n - newline and indent
# \t - increase indent
# \b - decrease indent ('outdent')
# \f - flush left (no indent)
# \cK - kill following semicolon, if any

# Semicolon handling:
#  - Individual statements are not deparsed with trailing semicolons.
#    (If necessary, \cK is tacked on to the end.)
#  - Whatever code joins statements together or emits them (lineseq,
#    scopeop, deparse_root) is responsible for adding semicolons where
#    necessary.
#  - use statements are deparsed with trailing semicolons because they are
#    immediately concatenated with the following statement.
#  - indent() removes semicolons wherever it sees \cK.


BEGIN { for (qw[ const stringify rv2sv list glob pushmark null aelem
                 kvaslice kvhslice padsv
                 nextstate dbstate rv2av rv2hv helem custom ]) {
    eval "sub OP_\U$_ () { " . opnumber($_) . "}"
}}

# _pessimise_walk(): recursively walk the optree of a sub,
# possibly undoing optimisations along the way.

sub _pessimise_walk {
    my ($self, $startop) = @_;

    return unless $$startop;
    my ($op, $prevop);
    for ($op = $startop; $$op; $prevop = $op, $op = $op->sibling) {
        my $ppname = $op->name;

        # pessimisations start here

        if ($ppname eq "padrange") {
            # remove PADRANGE:
            # the original optimisation either (1) changed this:
            #    pushmark -> (various pad and list and null ops) -> the_rest
            # or (2), for the = @_ case, changed this:
            #    pushmark -> gv[_] -> rv2av -> (pad stuff)       -> the_rest
            # into this:
            #    padrange ----------------------------------------> the_rest
            # so we just need to convert the padrange back into a
            # pushmark, and in case (1), set its op_next to op_sibling,
            # which is the head of the original chain of optimised-away
            # pad ops, or for (2), set it to sibling->first, which is
            # the original gv[_].

            $B::overlay->{$$op} = {
                    type => OP_PUSHMARK,
                    name => 'pushmark',
                    private => ($op->private & OPpLVAL_INTRO),
            };
        }

        # pessimisations end here

        if (class($op) eq 'PMOP') {
            if (ref($op->pmreplroot)
                && ${$op->pmreplroot}
                && $op->pmreplroot->isa( 'B::OP' ))
            {
                $self-> _pessimise_walk($op->pmreplroot);
            }

            # pessimise any /(?{...})/ code blocks
            my ($re, $cv);
            my $code_list = $op->code_list;
            if ($$code_list) {
                $self->_pessimise_walk($code_list);
            }
            elsif (${$re = $op->pmregexp} && ${$cv = $re->qr_anoncv}) {
                $code_list = $cv->ROOT      # leavesub
                               ->first      #   qr
                               ->code_list; #     list
                $self->_pessimise_walk($code_list);
            }
        }

        if ($op->flags & OPf_KIDS) {
            $self-> _pessimise_walk($op->first);
        }

    }
}


# _pessimise_walk_exe(): recursively walk the op_next chain of a sub,
# possibly undoing optimisations along the way.

sub _pessimise_walk_exe {
    my ($self, $startop, $visited) = @_;

    no warnings 'recursion';

    return unless $$startop;
    return if $visited->{$$startop};
    my ($op, $prevop);
    for ($op = $startop; $$op; $prevop = $op, $op = $op->next) {
        last if $visited->{$$op};
        $visited->{$$op} = 1;
        my $ppname = $op->name;
        if ($ppname =~
            /^((and|d?or)(assign)?|(map|grep)while|range|cond_expr|once)$/
            # entertry is also a logop, but its op_other invariably points
            # into the same chain as the main execution path, so we skip it
        ) {
            $self->_pessimise_walk_exe($op->other, $visited);
        }
        elsif ($ppname eq "subst") {
            $self->_pessimise_walk_exe($op->pmreplstart, $visited);
        }
        elsif ($ppname =~ /^(enter(loop|iter))$/) {
            # redoop and nextop will already be covered by the main block
            # of the loop
            $self->_pessimise_walk_exe($op->lastop, $visited);
        }

        # pessimisations start here
    }
}

# Go through an optree and "remove" some optimisations by using an
# overlay to selectively modify or un-null some ops. Deparsing in the
# absence of those optimisations is then easier.
#
# Note that older optimisations are not removed, as Deparse was already
# written to recognise them before the pessimise/overlay system was added.

sub pessimise {
    my ($self, $root, $start) = @_;

    no warnings 'recursion';
    # walk tree in root-to-branch order
    $self->_pessimise_walk($root);

    my %visited;
    # walk tree in execution order
    $self->_pessimise_walk_exe($start, \%visited);
}


sub null {
    my $op = shift;
    return class($op) eq "NULL";
}


# Add a CV to the list of subs that still need deparsing.

sub todo {
    my $self = shift;
    my($cv, $is_form, $name) = @_;
    my $cvfile = $cv->FILE//'';
    return unless ($cvfile eq $0 || exists $self->{files}{$cvfile});
    my $seq;
    if ($cv->OUTSIDE_SEQ) {
        $seq = $cv->OUTSIDE_SEQ;
    } elsif (!null($cv->START) and is_state($cv->START)) {
        $seq = $cv->START->cop_seq;
    } else {
        $seq = 0;
    }
    my $stash = $cv->STASH;
    if (class($stash) eq 'HV') {
        $self->{packs}{$stash->NAME}++;
    }
    push @{$self->{'subs_todo'}}, [$seq, $cv, $is_form, $name];
}


# Pop the next sub from the todo list and deparse it

sub next_todo {
    my $self = shift;
    my $ent = shift @{$self->{'subs_todo'}};
    my ($seq, $cv, $is_form, $name) = @$ent;

    # any 'use strict; package foo' that should come before the sub
    # declaration to sync with the first COP of the sub
    my $pragmata = '';
    if ($cv and !null($cv->START) and is_state($cv->START))  {
        $pragmata = $self->pragmata($cv->START);
    }

    if (ref $name) { # lexical sub
        # emit the sub.
        my @text;
        my $flags = $name->FLAGS;
        push @text,
            !$cv || $seq <= $name->COP_SEQ_RANGE_LOW
                ? $self->keyword($flags & SVpad_OUR
                                    ? "our"
                                    : $flags & SVpad_STATE
                                        ? "state"
                                        : "my") . " "
                : "";
        # XXX We would do $self->keyword("sub"), but ‘my CORE::sub’
        #     doesn’t work and ‘my sub’ ignores a &sub in scope.  I.e.,
        #     we have a core bug here.
        push @text, "sub " . substr $name->PVX, 1;
        if ($cv) {
            # my sub foo { }
            push @text,  " " . $self->deparse_sub($cv);
            $text[-1] =~ s/ ;$/;/;
        }
        else {
            # my sub foo;
            push @text, ";\n";
        }
        return $pragmata . join "", @text;
    }

    my $gv = $cv->GV;
    $name //= $self->gv_name($gv);
    if ($is_form) {
        return $pragmata . $self->keyword("format") . " $name =\n"
            . $self->deparse_format($cv). "\n";
    } else {
        my $use_dec;
        if ($name eq "BEGIN") {
            $use_dec = $self->begin_is_use($cv);
            if (defined ($use_dec) and $self->{'expand'} < 5) {
                return $pragmata if 0 == length($use_dec);

                #  XXX bit of a hack: Test::More's use_ok() method
                #  builds a fake use statement which deparses as, e.g.
                #      use Net::Ping (@{$args[0];});
                #  As well as being superfluous (the use_ok() is deparsed
                #  too) and ugly, it fails under use strict and otherwise
                #  makes use of a lexical var that's not in scope.
                #  So strip it out.
                return $pragmata
                        if $use_dec =~
                            m/
                                \A
                                use \s \S+ \s \(\@\{
                                (
                                    \s*\#line\ \d+\ \".*"\s*
                                )?
                                \$args\[0\];\}\);
                                \n
                                \Z
                            /x;

                $use_dec =~ s/^(use|no)\b/$self->keyword($1)/e;
            }
        }
        my $l = '';
        if ($self->{'linenums'}) {
            my $line = $gv->LINE;
            my $file = $gv->FILE;
            $l = "\n\f#line $line \"$file\"\n";
        }
        my $p = '';
        my $stash;
        if (class($cv->STASH) ne "SPECIAL") {
            $stash = $cv->STASH->NAME;
            if ($stash ne $self->{'curstash'}) {
                $p = $self->keyword("package") . " $stash;\n";
                $name = "$self->{'curstash'}::$name" unless $name =~ /::/;
                $self->{'curstash'} = $stash;
            }
        }
        if ($use_dec) {
            return "$pragmata$p$l$use_dec";
        }
        if ( $name !~ /::/ and $self->lex_in_scope("&$name")
                            || $self->lex_in_scope("&$name", 1) )
        {
            $name = "$self->{'curstash'}::$name";
        } elsif (defined $stash) {
            $name =~ s/^\Q$stash\E::(?!\z|.*::)//;
        }
        my $ret = "$pragmata${p}${l}" . $self->keyword("sub") . " $name "
              . $self->deparse_sub($cv);
        $self->{'subs_declared'}{$name} = 1;
        return $ret;
    }
}


# Return a "use" declaration for this BEGIN block, if appropriate
sub begin_is_use {
    my ($self, $cv) = @_;
    my $root = $cv->ROOT;
    local @$self{qw'curcv curcvlex'} = ($cv);
    local $B::overlay = {};
    $self->pessimise($root, $cv->START);
#require B::Debug;
#B::walkoptree($cv->ROOT, "debug");
    my $lineseq = $root->first;
    return if $lineseq->name ne "lineseq";

    my $req_op = $lineseq->first->sibling;
    return if $req_op->name ne "require";

    # maybe it's C<require expr> rather than C<require 'foo'>
    return if ($req_op->first->name ne 'const');

    my $module;
    if ($req_op->first->private & OPpCONST_BARE) {
        # Actually it should always be a bareword
        $module = $self->const_sv($req_op->first)->PV;
        $module =~ s[/][::]g;
        $module =~ s/.pm$//;
    }
    else {
        $module = $self->const($self->const_sv($req_op->first), 6);
    }

    my $version;
    my $version_op = $req_op->sibling;
    return if class($version_op) eq "NULL";
    if ($version_op->name eq "lineseq") {
        # We have a version parameter; skip nextstate & pushmark
        my $constop = $version_op->first->next->next;

        return unless $self->const_sv($constop)->PV eq $module;
        $constop = $constop->sibling;
        $version = $self->const_sv($constop);
        if (class($version) eq "IV") {
            $version = $version->int_value;
        } elsif (class($version) eq "NV") {
            $version = $version->NV;
        } elsif (class($version) ne "PVMG") {
            # Includes PVIV and PVNV
            $version = $version->PV;
        } else {
            # version specified as a v-string
            $version = 'v'.join '.', map ord, split //, $version->PV;
        }
        $constop = $constop->sibling;
        return if $constop->name ne "method_named";
        return if $self->meth_sv($constop)->PV ne "VERSION";
    }

    $lineseq = $version_op->sibling;
    return if $lineseq->name ne "lineseq";
    my $entersub = $lineseq->first->sibling;
    if ($entersub->name eq "stub") {
        return "use $module $version ();\n" if defined $version;
        return "use $module ();\n";
    }
    return if $entersub->name ne "entersub";

    # See if there are import arguments
    my $args = '';

    my $svop = $entersub->first->sibling; # Skip over pushmark
    return unless $self->const_sv($svop)->PV eq $module;

    # Pull out the arguments
    for ($svop=$svop->sibling; index($svop->name, "method_") != 0;
                $svop = $svop->sibling) {
        $args .= ", " if length($args);
        $args .= $self->deparse($svop, 6);
    }

    my $use = 'use';
    my $method_named = $svop;
    return if $method_named->name ne "method_named";
    my $method_name = $self->meth_sv($method_named)->PV;

    if ($method_name eq "unimport") {
        $use = 'no';
    }

    # Certain pragmas are dealt with using hint bits,
    # so we ignore them here
    if ($module eq 'strict' || $module eq 'integer'
        || $module eq 'bytes' || $module eq 'warnings'
        || $module eq 'feature') {
        return "";
    }

    if (defined $version && length $args) {
        return "$use $module $version ($args);\n";
    } elsif (defined $version) {
        return "$use $module $version;\n";
    } elsif (length $args) {
        return "$use $module ($args);\n";
    } else {
        return "$use $module;\n";
    }
}

sub stash_subs {
    my ($self, $pack, $seen) = @_;
    my (@ret, $stash);
    if (!defined $pack) {
        $pack = '';
        $stash = \%::;
    }
    else {
        $pack =~ s/(::)?$/::/;
        no strict 'refs';
        $stash = \%{"main::$pack"};
    }
    return
        if ($seen ||= {})->{
            $INC{"overload.pm"} ? overload::StrVal($stash) : $stash
           }++;
    my $stashobj = svref_2object($stash);
    my %stash = $stashobj->ARRAY;
    while (my ($key, $val) = each %stash) {
        my $flags = $val->FLAGS;
        if ($flags & SVf_ROK) {
            # A reference.  Dump this if it is a reference to a CV.  If it
            # is a constant acting as a proxy for a full subroutine, then
            # we may or may not have to dump it.  If some form of perl-
            # space visible code must have created it, be it a use
            # statement, or some direct symbol-table manipulation code that
            # we will deparse, then we don’t want to dump it.  If it is the
            # result of a declaration like sub f () { 42 } then we *do*
            # want to dump it.  The only way to distinguish these seems
            # to be the SVs_PADTMP flag on the constant, which is admit-
            # tedly a hack.
            my $class = class(my $referent = $val->RV);
            if ($class eq "CV") {
                $self->todo($referent, 0);
            } elsif (
                $class !~ /^(AV|HV|CV|FM|IO|SPECIAL)\z/
                # A more robust way to write that would be this, but B does
                # not provide the SVt_ constants:
                # ($referent->FLAGS & B::SVTYPEMASK) < B::SVt_PVAV
                and $referent->FLAGS & SVs_PADTMP
            ) {
                push @{$self->{'protos_todo'}}, [$pack . $key, $val];
            }
        } elsif ($flags & (SVf_POK|SVf_IOK)) {
            # Just a prototype. As an ugly but fairly effective way
            # to find out if it belongs here is to see if the AUTOLOAD
            # (if any) for the stash was defined in one of our files.
            my $A = $stash{"AUTOLOAD"};
            if (defined ($A) && class($A) eq "GV" && defined($A->CV)
                && class($A->CV) eq "CV") {
                my $AF = $A->FILE;
                next unless $AF eq $0 || exists $self->{'files'}{$AF};
            }
            push @{$self->{'protos_todo'}},
                 [$pack . $key, $flags & SVf_POK ? $val->PV: undef];
        } elsif (class($val) eq "GV") {
            if (class(my $cv = $val->CV) ne "SPECIAL") {
                next if $self->{'subs_done'}{$$val}++;

                # Ignore imposters (aliases etc)
                my $name = $cv->NAME_HEK;
                if(defined $name) {
                    # avoid using $cv->GV here because if the $val GV is
                    # an alias, CvGV() could upgrade the real stash entry
                    # from an RV to a GV
                    next unless $name eq $key;
                    next unless $$stashobj == ${$cv->STASH};
                }
                else {
                   next if $$val != ${$cv->GV};
                }

                $self->todo($cv, 0);
            }
            if (class(my $cv = $val->FORM) ne "SPECIAL") {
                next if $self->{'forms_done'}{$$val}++;
                next if $$val != ${$cv->GV};   # Ignore imposters
                $self->todo($cv, 1);
            }
            if (class($val->HV) ne "SPECIAL" && $key =~ /::$/) {
                $self->stash_subs($pack . $key, $seen);
            }
        }
    }
}

sub print_protos {
    my $self = shift;
    my $ar;
    my @ret;
    foreach $ar (@{$self->{'protos_todo'}}) {
        if (ref $ar->[1]) {
            # Only print a constant if it occurs in the same package as a
            # dumped sub.  This is not perfect, but a heuristic that will
            # hopefully work most of the time.  Ideally we would use
            # CvFILE, but a constant stub has no CvFILE.
            my $pack = ($ar->[0] =~ /(.*)::/)[0];
            next if $pack and !$self->{packs}{$pack}
        }
        my $body = defined $ar->[1]
                ? ref $ar->[1]
                    ? " () {\n    " . $self->const($ar->[1]->RV,0) . ";\n}"
                    : " (". $ar->[1] . ");"
                : ";";
        push @ret, "sub " . $ar->[0] .  "$body\n";
    }
    delete $self->{'protos_todo'};
    return @ret;
}

sub style_opts {
    my $self = shift;
    my $opts = shift;
    my $opt;
    while (length($opt = substr($opts, 0, 1))) {
        if ($opt eq "C") {
            $self->{'cuddle'} = " ";
            $opts = substr($opts, 1);
        } elsif ($opt eq "i") {
            $opts =~ s/^i(\d+)//;
            $self->{'indent_size'} = $1;
        } elsif ($opt eq "T") {
            $self->{'use_tabs'} = 1;
            $opts = substr($opts, 1);
        } elsif ($opt eq "v") {
            $opts =~ s/^v([^.]*)(.|$)//;
            $self->{'ex_const'} = $1;
        }
    }
}

sub new {
    my $class = shift;
    my $self = bless {}, $class;
    $self->{'cuddle'} = "\n";
    $self->{'curcop'} = undef;
    $self->{'curstash'} = "main";
    $self->{'ex_const'} = "'???'";
    $self->{'expand'} = 0;
    $self->{'files'} = {};
    $self->{'packs'} = {};
    $self->{'indent_size'} = 4;
    $self->{'linenums'} = 0;
    $self->{'parens'} = 0;
    $self->{'subs_todo'} = [];
    $self->{'unquote'} = 0;
    $self->{'use_dumper'} = 0;
    $self->{'use_tabs'} = 0;

    $self->{'ambient_arybase'} = 0;
    $self->{'ambient_warnings'} = undef; # Assume no lexical warnings
    $self->{'ambient_hints'} = 0;
    $self->{'ambient_hinthash'} = undef;
    $self->init();

    while (my $arg = shift @_) {
        if ($arg eq "-d") {
            $self->{'use_dumper'} = 1;
            require Data::Dumper;
        } elsif ($arg =~ /^-f(.*)/) {
            $self->{'files'}{$1} = 1;
        } elsif ($arg eq "-l") {
            $self->{'linenums'} = 1;
        } elsif ($arg eq "-p") {
            $self->{'parens'} = 1;
        } elsif ($arg eq "-P") {
            $self->{'noproto'} = 1;
        } elsif ($arg eq "-q") {
            $self->{'unquote'} = 1;
        } elsif (substr($arg, 0, 2) eq "-s") {
            $self->style_opts(substr $arg, 2);
        } elsif ($arg =~ /^-x(\d)$/) {
            $self->{'expand'} = $1;
        }
    }
    return $self;
}

{
    # Mask out the bits that L<warnings::register> uses
    my $WARN_MASK;
    BEGIN {
        $WARN_MASK = $warnings::Bits{all} | $warnings::DeadBits{all};
    }
    sub WARN_MASK () {
        return $WARN_MASK;
    }
}

# Initialise the contextual information, either from
# defaults provided with the ambient_pragmas method,
# or from perl's own defaults otherwise.
sub init {
    my $self = shift;

    $self->{'arybase'}  = $self->{'ambient_arybase'};
    $self->{'warnings'} = defined ($self->{'ambient_warnings'})
                                ? $self->{'ambient_warnings'} & WARN_MASK
                                : undef;
    $self->{'hints'}    = $self->{'ambient_hints'};
    $self->{'hinthash'} = $self->{'ambient_hinthash'};

    # also a convenient place to clear out subs_declared
    delete $self->{'subs_declared'};
}

sub compile {
    my(@args) = @_;
    return sub {
        my $self = B::Deparse->new(@args);
        # First deparse command-line args
        if (defined $^I) { # deparse -i
            print q(BEGIN { $^I = ).perlstring($^I).qq(; }\n);
        }
        if ($^W) { # deparse -w
            print qq(BEGIN { \$^W = $^W; }\n);
        }
        if ($/ ne "\n" or defined $O::savebackslash) { # deparse -l and -0
            my $fs = perlstring($/) || 'undef';
            my $bs = perlstring($O::savebackslash) || 'undef';
            print qq(BEGIN { \$/ = $fs; \$\\ = $bs; }\n);
        }
        my @BEGINs  = B::begin_av->isa("B::AV") ? B::begin_av->ARRAY : ();
        my @UNITCHECKs = B::unitcheck_av->isa("B::AV")
            ? B::unitcheck_av->ARRAY
            : ();
        my @CHECKs  = B::check_av->isa("B::AV") ? B::check_av->ARRAY : ();
        my @INITs   = B::init_av->isa("B::AV") ? B::init_av->ARRAY : ();
        my @ENDs    = B::end_av->isa("B::AV") ? B::end_av->ARRAY : ();
        my @names = qw(BEGIN UNITCHECK CHECK INIT END);
        my @blocks = \(@BEGINs, @UNITCHECKs, @CHECKs, @INITs, @ENDs);
        while (@names) {
            my ($name, $blocks) = (shift @names, shift @blocks);
            for my $block (@$blocks) {
                $self->todo($block, 0, $name);
            }
        }
        $self->stash_subs();
        local($SIG{"__DIE__"}) =
          sub {
              if ($self->{'curcop'}) {
                  my $cop = $self->{'curcop'};
                  my($line, $file) = ($cop->line, $cop->file);
                  print STDERR "While deparsing $file near line $line,\n";
              }
            };
        $self->{'curcv'} = main_cv;
        $self->{'curcvlex'} = undef;
        print $self->print_protos;
        @{$self->{'subs_todo'}} =
          sort {$a->[0] <=> $b->[0]} @{$self->{'subs_todo'}};
        my $root = main_root;
        local $B::overlay = {};
        unless (null $root) {
            $self->pad_subs($self->{'curcv'});
            # Check for a stub-followed-by-ex-cop, resulting from a program
            # consisting solely of sub declarations.  For backward-compati-
            # bility (and sane output) we don’t want to emit the stub.
            #   leave
            #     enter
            #     stub
            #     ex-nextstate (or ex-dbstate)
            my $kid;
            if ( $root->name eq 'leave'
             and ($kid = $root->first)->name eq 'enter'
             and !null($kid = $kid->sibling) and $kid->name eq 'stub'
             and !null($kid = $kid->sibling) and $kid->name eq 'null'
             and class($kid) eq 'COP' and null $kid->sibling )
            {
                # ignore
            } else {
                $self->pessimise($root, main_start);
                print $self->indent($self->deparse_root($root)), "\n";
            }
        }
        my @text;
        while (scalar(@{$self->{'subs_todo'}})) {
            push @text, $self->next_todo;
        }
        print $self->indent(join("", @text)), "\n" if @text;

        # Print __DATA__ section, if necessary
        no strict 'refs';
        my $laststash = defined $self->{'curcop'}
            ? $self->{'curcop'}->stash->NAME : $self->{'curstash'};
        if (defined *{$laststash."::DATA"}{IO}) {
            print $self->keyword("package") . " $laststash;\n"
                unless $laststash eq $self->{'curstash'};
            print $self->keyword("__DATA__") . "\n";
            print readline(*{$laststash."::DATA"});
        }
    }
}

sub coderef2text {
    my $self = shift;
    my $sub = shift;
    croak "Usage: ->coderef2text(CODEREF)" unless UNIVERSAL::isa($sub, "CODE");

    $self->init();
    local $self->{in_coderef2text} = 1;
    return $self->indent($self->deparse_sub(svref_2object($sub)));
}

my %strict_bits = do {
    local $^H;
    map +($_ => strict::bits($_)), qw/refs subs vars/
};

sub ambient_pragmas {
    my $self = shift;
    my ($arybase, $hint_bits, $warning_bits, $hinthash) = (0, 0);

    while (@_ > 1) {
        my $name = shift();
        my $val  = shift();

        if ($name eq 'strict') {
            require strict;

            if ($val eq 'none') {
                $hint_bits &= $strict_bits{$_} for qw/refs subs vars/;
                next();
            }

            my @names;
            if ($val eq "all") {
                @names = qw/refs subs vars/;
            }
            elsif (ref $val) {
                @names = @$val;
            }
            else {
                @names = split' ', $val;
            }
            $hint_bits |= $strict_bits{$_} for @names;
        }

        elsif ($name eq '$[') {
            if (OPpCONST_ARYBASE) {
                $arybase = $val;
            } else {
                croak "\$[ can't be non-zero on this perl" unless $val == 0;
            }
        }

        elsif ($name eq 'integer'
            || $name eq 'bytes'
            || $name eq 'utf8') {
            require "$name.pm";
            if ($val) {
                $hint_bits |= ${$::{"${name}::"}{"hint_bits"}};
            }
            else {
                $hint_bits &= ~${$::{"${name}::"}{"hint_bits"}};
            }
        }

        elsif ($name eq 're') {
            require re;
            if ($val eq 'none') {
                $hint_bits &= ~re::bits(qw/taint eval/);
                next();
            }

            my @names;
            if ($val eq 'all') {
                @names = qw/taint eval/;
            }
            elsif (ref $val) {
                @names = @$val;
            }
            else {
                @names = split' ',$val;
            }
            $hint_bits |= re::bits(@names);
        }

        elsif ($name eq 'warnings') {
            if ($val eq 'none') {
                $warning_bits = $warnings::NONE;
                next();
            }

            my @names;
            if (ref $val) {
                @names = @$val;
            }
            else {
                @names = split/\s+/, $val;
            }

            $warning_bits = $warnings::NONE if !defined ($warning_bits);
            $warning_bits |= warnings::bits(@names);
        }

        elsif ($name eq 'warning_bits') {
            $warning_bits = $val;
        }

        elsif ($name eq 'hint_bits') {
            $hint_bits = $val;
        }

        elsif ($name eq '%^H') {
            $hinthash = $val;
        }

        else {
            croak "Unknown pragma type: $name";
        }
    }
    if (@_) {
        croak "The ambient_pragmas method expects an even number of args";
    }

    $self->{'ambient_arybase'} = $arybase;
    $self->{'ambient_warnings'} = $warning_bits;
    $self->{'ambient_hints'} = $hint_bits;
    $self->{'ambient_hinthash'} = $hinthash;
}

# This method is the inner loop, so try to keep it simple
sub deparse {
    my $self = shift;
    my($op, $cx) = @_;

    Carp::confess("Null op in deparse") if !defined($op)
                                        || class($op) eq "NULL";
    my $meth = "pp_" . $op->name;
    return $self->$meth($op, $cx);
}

sub indent {
    my $self = shift;
    my $txt = shift;
    # \cK also swallows a preceding line break when followed by a
    # semicolon.
    $txt =~ s/\n\cK;//g;
    my @lines = split(/\n/, $txt);
    my $leader = "";
    my $level = 0;
    my $line;
    for $line (@lines) {
        my $cmd = substr($line, 0, 1);
        if ($cmd eq "\t" or $cmd eq "\b") {
            $level += ($cmd eq "\t" ? 1 : -1) * $self->{'indent_size'};
            if ($self->{'use_tabs'}) {
                $leader = "\t" x ($level / 8) . " " x ($level % 8);
            } else {
                $leader = " " x $level;
            }
            $line = substr($line, 1);
        }
        if (index($line, "\f") > 0) {
                $line =~ s/\f/\n/;
        }
        if (substr($line, 0, 1) eq "\f") {
            $line = substr($line, 1); # no indent
        } else {
            $line = $leader . $line;
        }
        $line =~ s/\cK;?//g;
    }
    return join("\n", @lines);
}

sub pad_subs {
    my ($self, $cv) = @_;
    my $padlist = $cv->PADLIST;
    my @names = $padlist->ARRAYelt(0)->ARRAY;
    my @values = $padlist->ARRAYelt(1)->ARRAY;
    my @todo;
  PADENTRY:
    for my $ix (0.. $#names) { for $_ ($names[$ix]) {
        next if class($_) eq "SPECIAL";
        my $name = $_->PVX;
        if (defined $name && $name =~ /^&./) {
            my $low = $_->COP_SEQ_RANGE_LOW;
            my $flags = $_->FLAGS;
            my $outer = $flags & PADNAMEt_OUTER;
            if ($flags & SVpad_OUR) {
                push @todo, [$low, undef, 0, $_]
                          # [seq, no cv, not format, padname]
                    unless $outer;
                next;
            }
            my $protocv = $flags & SVpad_STATE
                ? $values[$ix]
                : $_->PROTOCV;
            if (class ($protocv) ne 'CV') {
                my $flags = $flags;
                my $cv = $cv;
                my $name = $_;
                while ($flags & PADNAMEt_OUTER && class ($protocv) ne 'CV')
                {
                    $cv = $cv->OUTSIDE;
                    next PADENTRY if class($cv) eq 'SPECIAL'; # XXX freed?
                    my $padlist = $cv->PADLIST;
                    my $ix = $name->PARENT_PAD_INDEX;
                    $name = $padlist->NAMES->ARRAYelt($ix);
                    $flags = $name->FLAGS;
                    $protocv = $flags & SVpad_STATE
                        ? $padlist->ARRAYelt(1)->ARRAYelt($ix)
                        : $name->PROTOCV;
                }
            }
            my $defined_in_this_sub = ${$protocv->OUTSIDE} == $$cv || do {
                my $other = $protocv->PADLIST;
                $$other && $other->outid == $padlist->id;
            };
            if ($flags & PADNAMEt_OUTER) {
                next unless $defined_in_this_sub;
                push @todo, [$protocv->OUTSIDE_SEQ, $protocv, 0, $_];
                next;
            }
            my $outseq = $protocv->OUTSIDE_SEQ;
            if ($outseq <= $low) {
                # defined before its name is visible, so it’s gotta be
                # declared and defined at once: my sub foo { ... }
                push @todo, [$low, $protocv, 0, $_];
            }
            else {
                # declared and defined separately: my sub f; sub f { ... }
                push @todo, [$low, undef, 0, $_];
                push @todo, [$outseq, $protocv, 0, $_]
                    if $defined_in_this_sub;
            }
        }
    }}
    @{$self->{'subs_todo'}} =
        sort {$a->[0] <=> $b->[0]} @{$self->{'subs_todo'}}, @todo
}


# deparse_argops(): deparse, if possible, a sequence of argcheck + argelem
# ops into a subroutine signature. If successful, return the first op
# following the signature ops plus the signature string; else return the
# empty list.
#
# Normally a bunch of argelem ops will have been generated by the
# signature parsing, but it's possible that ops have been added manually
# or altered. In this case we "return ()" and fall back to general
# deparsing of the individual sigelems as 'my $x = $_[N]' etc.
#
# We're only called if the first two ops are nextstate and argcheck.

sub deparse_argops {
    my ($self, $firstop, $cv) = @_;

    my @sig;
    my $o = $firstop;
    return if $o->label; #first nextstate;

    # OP_ARGCHECK

    $o = $o->sibling;
    my ($params, $opt_params, $slurpy) = $o->aux_list($cv);
    my $mandatory = $params - $opt_params;
    my $seen_slurpy = 0;
    my $last_ix = -1;

    # keep looking for valid nextstate + argelem pairs

    while (1) {
        # OP_NEXTSTATE
        $o = $o->sibling;
        last unless $$o;
        last unless $o->name =~ /^(next|db)state$/;
        last if $o->label;

        # OP_ARGELEM
        my $o2 = $o->sibling;
        last unless $$o2;

        if ($o2->name eq 'argelem') {
            my $ix  = $o2->string($cv);
            while (++$last_ix < $ix) {
                push @sig, $last_ix <  $mandatory ? '$' : '$=';
            }
            my $var = $self->padname($o2->targ);
            if ($var =~ /^[@%]/) {
                return if $seen_slurpy;
                $seen_slurpy = 1;
                return if $ix != $params or !$slurpy
                            or substr($var,0,1) ne $slurpy;
            }
            else {
                return if $ix >= $params;
            }
            if ($o2->flags & OPf_KIDS) {
                my $kid = $o2->first;
                return unless $$kid and $kid->name eq 'argdefelem';
                my $def = $self->deparse($kid->first, 7);
                $def = "($def)" if $kid->first->flags & OPf_PARENS;
                $var .= " = $def";
            }
            push @sig, $var;
        }
        elsif ($o2->name eq 'null'
               and ($o2->flags & OPf_KIDS)
               and $o2->first->name eq 'argdefelem')
        {
            # special case - a void context default expression: $ = expr

            my $defop = $o2->first;
            my $ix = $defop->targ;
            while (++$last_ix < $ix) {
                push @sig, $last_ix <  $mandatory ? '$' : '$=';
            }
            return if $last_ix >= $params
                    or $last_ix < $mandatory;
            my $def = $self->deparse($defop->first, 7);
            $def = "($def)" if $defop->first->flags & OPf_PARENS;
            push @sig, '$ = ' . $def;
        }
        else {
            last;
        }

        $o = $o2;
    }

    while (++$last_ix < $params) {
        push @sig, $last_ix <  $mandatory ? '$' : '$=';
    }
    push @sig, $slurpy if $slurpy and !$seen_slurpy;

    return ($o, join(', ', @sig));
}

# Deparse a sub. Returns everything except the 'sub foo',
# e.g.  ($$) : method { ...; }
# or    ($a, $b) : prototype($$) lvalue;

sub deparse_sub {
    my $self = shift;
    my $cv = shift;
    my @attrs;
    my $protosig; # prototype or signature (what goes in the (....))

Carp::confess("NULL in deparse_sub") if !defined($cv) || $cv->isa("B::NULL");
Carp::confess("SPECIAL in deparse_sub") if $cv->isa("B::SPECIAL");
    local $self->{'curcop'} = $self->{'curcop'};

    my $has_sig = $self->{hinthash}{feature_signatures};
    if ($cv->FLAGS & SVf_POK) {
        my $proto = $cv->PV;
        if ($has_sig) {
            push @attrs, "prototype($proto)";
        }
        else {
            $protosig = $proto;
        }
    }
    if ($cv->CvFLAGS & (CVf_METHOD|CVf_LOCKED|CVf_LVALUE|CVf_ANONCONST)) {
        push @attrs, "lvalue" if $cv->CvFLAGS & CVf_LVALUE;
        push @attrs, "method" if $cv->CvFLAGS & CVf_METHOD;
        push @attrs, "const"  if $cv->CvFLAGS & CVf_ANONCONST;
    }

    local($self->{'curcv'}) = $cv;
    local($self->{'curcvlex'});
    local(@$self{qw'curstash warnings hints hinthash'})
                = @$self{qw'curstash warnings hints hinthash'};
    my $body;
    my $root = $cv->ROOT;
    local $B::overlay = {};
    if (not null $root) {
        $self->pad_subs($cv);
        $self->pessimise($root, $cv->START);
        my $lineseq = $root->first;
        if ($lineseq->name eq "lineseq") {
            my $firstop = $lineseq->first;

            if ($has_sig) {
                my $o2;
                # try to deparse first few ops as a signature if possible
                if (     $$firstop
                     and $firstop->name =~  /^(next|db)state$/
                     and (($o2 = $firstop->sibling))
                     and $$o2)
                {
                    if ($o2->name eq 'argcheck') {
                        my ($nexto, $sig) = $self->deparse_argops($firstop, $cv);
                        if (defined $nexto) {
                            $firstop = $nexto;
                            $protosig = $sig;
                        }
                    }
                }
            }

            my @ops;
            for (my $o = $firstop; $$o; $o=$o->sibling) {
                push @ops, $o;
            }
            $body = $self->lineseq(undef, 0, @ops).";";
            if (!$has_sig and $ops[-1]->name =~ /^(next|db)state$/) {
                # this handles void context in
                #   use feature signatures; sub ($=1) {}
                $body .= "\n()";
            }
            my $scope_en = $self->find_scope_en($lineseq);
            if (defined $scope_en) {
                my $subs = join"", $self->seq_subs($scope_en);
                $body .= ";\n$subs" if length($subs);
            }
        }
        else {
            $body = $self->deparse($root->first, 0);
        }
        $body = "{\n\t$body\n\b}";
    }
    else {
        my $sv = $cv->const_sv;
        if ($$sv) {
            # uh-oh. inlinable sub... format it differently
            $body = "{ " . $self->const($sv, 0) . " }\n";
        } else { # XSUB? (or just a declaration)
            $body = ';'
        }
    }
    $protosig = defined $protosig ? "($protosig) " : "";
    my $attrs = '';
    $attrs = ': ' . join('', map "$_ ", @attrs) if @attrs;
    return "$protosig$attrs$body\n";
}

sub deparse_format {
    my $self = shift;
    my $form = shift;
    my @text;
    local($self->{'curcv'}) = $form;
    local($self->{'curcvlex'});
    local($self->{'in_format'}) = 1;
    local(@$self{qw'curstash warnings hints hinthash'})
                = @$self{qw'curstash warnings hints hinthash'};
    my $op = $form->ROOT;
    local $B::overlay = {};
    $self->pessimise($op, $form->START);
    my $kid;
    return "\f." if $op->first->name eq 'stub'
                || $op->first->name eq 'nextstate';
    $op = $op->first->first; # skip leavewrite, lineseq
    while (not null $op) {
        $op = $op->sibling; # skip nextstate
        my @exprs;
        $kid = $op->first->sibling; # skip pushmark
        push @text, "\f".$self->const_sv($kid)->PV;
        $kid = $kid->sibling;
        for (; not null $kid; $kid = $kid->sibling) {
            push @exprs, $self->deparse($kid, -1);
            $exprs[-1] =~ s/;\z//;
        }
        push @text, "\f".join(", ", @exprs)."\n" if @exprs;
        $op = $op->sibling;
    }
    return join("", @text) . "\f.";
}

sub is_scope {
    my $op = shift;
    return $op->name eq "leave" || $op->name eq "scope"
      || $op->name eq "lineseq"
        || ($op->name eq "null" && class($op) eq "UNOP"
            && (is_scope($op->first) || $op->first->name eq "enter"));
}

sub is_state {
    my $name = $_[0]->name;
    return $name eq "nextstate" || $name eq "dbstate" || $name eq "setstate";
}

sub is_miniwhile { # check for one-line loop ('foo() while $y--')
    my $op = shift;
    return (!null($op) and null($op->sibling)
            and $op->name eq "null" and class($op) eq "UNOP"
            and (($op->first->name =~ /^(and|or)$/
                  and $op->first->first->sibling->name eq "lineseq")
                 or ($op->first->name eq "lineseq"
                     and not null $op->first->first->sibling
                     and $op->first->first->sibling->name eq "unstack")
                 ));
}

# Check if the op and its sibling are the initialization and the rest of a
# for (..;..;..) { ... } loop
sub is_for_loop {
    my $op = shift;
    # This OP might be almost anything, though it won't be a
    # nextstate. (It's the initialization, so in the canonical case it
    # will be an sassign.) The sibling is (old style) a lineseq whose
    # first child is a nextstate and whose second is a leaveloop, or
    # (new style) an unstack whose sibling is a leaveloop.
    my $lseq = $op->sibling;
    return 0 unless !is_state($op) and !null($lseq);
    if ($lseq->name eq "lineseq") {
        if ($lseq->first && !null($lseq->first) && is_state($lseq->first)
            && (my $sib = $lseq->first->sibling)) {
            return (!null($sib) && $sib->name eq "leaveloop");
        }
    } elsif ($lseq->name eq "unstack" && ($lseq->flags & OPf_SPECIAL)) {
        my $sib = $lseq->sibling;
        return $sib && !null($sib) && $sib->name eq "leaveloop";
    }
    return 0;
}

sub is_scalar {
    my $op = shift;
    return ($op->name eq "rv2sv" or
            $op->name eq "padsv" or
            $op->name eq "gv" or # only in array/hash constructs
            $op->flags & OPf_KIDS && !null($op->first)
              && $op->first->name eq "gvsv");
}

sub maybe_parens {
    my $self = shift;
    my($text, $cx, $prec) = @_;
    if ($prec < $cx              # unary ops nest just fine
        or $prec == $cx and $cx != 4 and $cx != 16 and $cx != 21
        or $self->{'parens'})
    {
        $text = "($text)";
        # In a unop, let parent reuse our parens; see maybe_parens_unop
        $text = "\cS" . $text if $cx == 16;
        return $text;
    } else {
        return $text;
    }
}

# same as above, but get around the 'if it looks like a function' rule
sub maybe_parens_unop {
    my $self = shift;
    my($name, $kid, $cx) = @_;
    if ($cx > 16 or $self->{'parens'}) {
        $kid =  $self->deparse($kid, 1);
        if ($name eq "umask" && $kid =~ /^\d+$/) {
            $kid = sprintf("%#o", $kid);
        }
        return $self->keyword($name) . "($kid)";
    } else {
        $kid = $self->deparse($kid, 16);
        if ($name eq "umask" && $kid =~ /^\d+$/) {
            $kid = sprintf("%#o", $kid);
        }
        $name = $self->keyword($name);
        if (substr($kid, 0, 1) eq "\cS") {
            # use kid's parens
            return $name . substr($kid, 1);
        } elsif (substr($kid, 0, 1) eq "(") {
            # avoid looks-like-a-function trap with extra parens
            # ('+' can lead to ambiguities)
            return "$name(" . $kid  . ")";
        } else {
            return "$name $kid";
        }
    }
}

sub maybe_parens_func {
    my $self = shift;
    my($func, $text, $cx, $prec) = @_;
    if ($prec <= $cx or substr($text, 0, 1) eq "(" or $self->{'parens'}) {
        return "$func($text)";
    } else {
        return "$func $text";
    }
}

sub find_our_type {
    my ($self, $name) = @_;
    $self->populate_curcvlex() if !defined $self->{'curcvlex'};
    my $seq = $self->{'curcop'} ? $self->{'curcop'}->cop_seq : 0;
    for my $a (@{$self->{'curcvlex'}{"o$name"}}) {
        my ($st, undef, $padname) = @$a;
        if ($st >= $seq && $padname->FLAGS & SVpad_TYPED) {
            return $padname->SvSTASH->NAME;
        }
    }
    return '';
}

sub maybe_local {
    my $self = shift;
    my($op, $cx, $text) = @_;
    my $name = $op->name;
    my $our_intro = ($name =~ /^(?:(?:gv|rv2)[ash]v|split|refassign
                                  |lv(?:av)?ref)$/x)
                        ? OPpOUR_INTRO
                        : 0;
    my $lval_intro = $name eq 'split' ? 0 : OPpLVAL_INTRO;
    # The @a in \(@a) isn't in ref context, but only when the
    # parens are there.
    my $need_parens = $self->{'in_refgen'} && $name =~ /[ah]v\z/
                   && ($op->flags & (OPf_PARENS|OPf_REF)) == OPf_PARENS;
    if ((my $priv = $op->private) & ($lval_intro|$our_intro)) {
        my @our_local;
        push @our_local, "local" if $priv & $lval_intro;
        push @our_local, "our"   if $priv & $our_intro;
        my $our_local = join " ", map $self->keyword($_), @our_local;
        if( $our_local[-1] eq 'our' ) {
            if ( $text !~ /^\W(\w+::)*\w+\z/
             and !utf8::decode($text) || $text !~ /^\W(\w+::)*\w+\z/
            ) {
                die "Unexpected our($text)\n";
            }
            $text =~ s/(\w+::)+//;

            if (my $type = $self->find_our_type($text)) {
                $our_local .= ' ' . $type;
            }
        }
        return $need_parens ? "($text)" : $text
            if $self->{'avoid_local'}{$$op};
        if ($need_parens) {
            return "$our_local($text)";
        } elsif (want_scalar($op)) {
            return "$our_local $text";
        } else {
            return $self->maybe_parens_func("$our_local", $text, $cx, 16);
        }
    } else {
        return $need_parens ? "($text)" : $text;
    }
}

sub maybe_targmy {
    my $self = shift;
    my($op, $cx, $func, @args) = @_;
    if ($op->private & OPpTARGET_MY) {
        my $var = $self->padname($op->targ);
        my $val = $func->($self, $op, 7, @args);
        return $self->maybe_parens("$var = $val", $cx, 7);
    } else {
        return $func->($self, $op, $cx, @args);
    }
}

sub padname_sv {
    my $self = shift;
    my $targ = shift;
    return $self->{'curcv'}->PADLIST->ARRAYelt(0)->ARRAYelt($targ);
}

sub maybe_my {
    my $self = shift;
    my($op, $cx, $text, $padname, $forbid_parens) = @_;
    # The @a in \(@a) isn't in ref context, but only when the
    # parens are there.
    my $need_parens = !$forbid_parens && $self->{'in_refgen'}
                   && $op->name =~ /[ah]v\z/
                   && ($op->flags & (OPf_PARENS|OPf_REF)) == OPf_PARENS;
    # The @a in \my @a must not have parens.
    if (!$need_parens && $self->{'in_refgen'}) {
        $forbid_parens = 1;
    }
    if ($op->private & OPpLVAL_INTRO and not $self->{'avoid_local'}{$$op}) {
        # Check $padname->FLAGS for statehood, rather than $op->private,
        # because enteriter ops do not carry the flag.
        my $my =
            $self->keyword($padname->FLAGS & SVpad_STATE ? "state" : "my");
        if ($padname->FLAGS & SVpad_TYPED) {
            $my .= ' ' . $padname->SvSTASH->NAME;
        }
        if ($need_parens) {
            return "$my($text)";
        } elsif ($forbid_parens || want_scalar($op)) {
            return "$my $text";
        } else {
            return $self->maybe_parens_func($my, $text, $cx, 16);
        }
    } else {
        return $need_parens ? "($text)" : $text;
    }
}

# The following OPs don't have functions:

# pp_padany -- does not exist after parsing

sub AUTOLOAD {
    if ($AUTOLOAD =~ s/^.*::pp_//) {
        warn "unexpected OP_".
          ($_[1]->type == OP_CUSTOM ? "CUSTOM ($AUTOLOAD)" : uc $AUTOLOAD);
        return "XXX";
    } else {
        die "Undefined subroutine $AUTOLOAD called";
    }
}

sub DESTROY {}  #       Do not AUTOLOAD

# $root should be the op which represents the root of whatever
# we're sequencing here. If it's undefined, then we don't append
# any subroutine declarations to the deparsed ops, otherwise we
# append appropriate declarations.
sub lineseq {
    my($self, $root, $cx, @ops) = @_;
    my($expr, @exprs);

    my $out_cop = $self->{'curcop'};
    my $out_seq = defined($out_cop) ? $out_cop->cop_seq : undef;
    my $limit_seq;
    if (defined $root) {
        $limit_seq = $out_seq;
        my $nseq;
        $nseq = $self->find_scope_st($root->sibling) if ${$root->sibling};
        $limit_seq = $nseq if !defined($limit_seq)
                           or defined($nseq) && $nseq < $limit_seq;
    }
    $limit_seq = $self->{'limit_seq'}
        if defined($self->{'limit_seq'})
        && (!defined($limit_seq) || $self->{'limit_seq'} < $limit_seq);
    local $self->{'limit_seq'} = $limit_seq;

    $self->walk_lineseq($root, \@ops,
                       sub { push @exprs, $_[0]} );

    my $sep = $cx ? '; ' : ";\n";
    my $body = join($sep, grep {length} @exprs);
    my $subs = "";
    if (defined $root && defined $limit_seq && !$self->{'in_format'}) {
        $subs = join "\n", $self->seq_subs($limit_seq);
    }
    return join($sep, grep {length} $body, $subs);
}

sub scopeop {
    my($real_block, $self, $op, $cx) = @_;
    my $kid;
    my @kids;

    local(@$self{qw'curstash warnings hints hinthash'})
                = @$self{qw'curstash warnings hints hinthash'} if $real_block;
    if ($real_block) {
        $kid = $op->first->sibling; # skip enter
        if (is_miniwhile($kid)) {
            my $top = $kid->first;
            my $name = $top->name;
            if ($name eq "and") {
                $name = $self->keyword("while");
            } elsif ($name eq "or") {
                $name = $self->keyword("until");
            } else { # no conditional -> while 1 or until 0
                return $self->deparse($top->first, 1) . " "
                     . $self->keyword("while") . " 1";
            }
            my $cond = $top->first;
            my $body = $cond->sibling->first; # skip lineseq
            $cond = $self->deparse($cond, 1);
            $body = $self->deparse($body, 1);
            return "$body $name $cond";
        }
    } else {
        $kid = $op->first;
    }
    for (; !null($kid); $kid = $kid->sibling) {
        push @kids, $kid;
    }
    if ($cx > 0) { # inside an expression, (a do {} while for lineseq)
        my $body = $self->lineseq($op, 0, @kids);
        return is_lexical_subs(@kids)
                ? $body
                : ($self->lex_in_scope("&do") ? "CORE::do" : "do")
                 . " {\n\t$body\n\b}";
    } else {
        my $lineseq = $self->lineseq($op, $cx, @kids);
        return (length ($lineseq) ? "$lineseq;" : "");
    }
}

sub pp_scope { scopeop(0, @_); }
sub pp_lineseq { scopeop(0, @_); }
sub pp_leave { scopeop(1, @_); }

# This is a special case of scopeop and lineseq, for the case of the
# main_root. The difference is that we print the output statements as
# soon as we get them, for the sake of impatient users.
sub deparse_root {
    my $self = shift;
    my($op) = @_;
    local(@$self{qw'curstash warnings hints hinthash'})
      = @$self{qw'curstash warnings hints hinthash'};
    my @kids;
    return if null $op->first; # Can happen, e.g., for Bytecode without -k
    for (my $kid = $op->first->sibling; !null($kid); $kid = $kid->sibling) {
        push @kids, $kid;
    }
    $self->walk_lineseq($op, \@kids,
                        sub { return unless length $_[0];
                              print $self->indent($_[0].';');
                              print "\n"
                                unless $_[1] == $#kids;
                          });
}

sub walk_lineseq {
    my ($self, $op, $kids, $callback) = @_;
    my @kids = @$kids;
    for (my $i = 0; $i < @kids; $i++) {
        my $expr = "";
        if (is_state $kids[$i]) {
            $expr = $self->deparse($kids[$i++], 0);
            if ($i > $#kids) {
                $callback->($expr, $i);
                last;
            }
        }
        if (is_for_loop($kids[$i])) {
            $callback->($expr . $self->for_loop($kids[$i], 0),
                $i += $kids[$i]->sibling->name eq "unstack" ? 2 : 1);
            next;
        }
        my $expr2 = $self->deparse($kids[$i], (@kids != 1)/2);
        $expr2 =~ s/^sub :(?!:)/+sub :/; # statement label otherwise
        $expr .= $expr2;
        $callback->($expr, $i);
    }
}

# The BEGIN {} is used here because otherwise this code isn't executed
# when you run B::Deparse on itself.
my %globalnames;
BEGIN { map($globalnames{$_}++, "SIG", "STDIN", "STDOUT", "STDERR", "INC",
            "ENV", "ARGV", "ARGVOUT", "_"); }

sub gv_name {
    my $self = shift;
    my $gv = shift;
    my $raw = shift;
#Carp::confess() unless ref($gv) eq "B::GV";
    my $cv = $gv->FLAGS & SVf_ROK ? $gv->RV : 0;
    my $stash = ($cv || $gv)->STASH->NAME;
    my $name = $raw
        ? $cv ? $cv->NAME_HEK || $cv->GV->NAME : $gv->NAME
        : $cv
            ? B::safename($cv->NAME_HEK || $cv->GV->NAME)
            : $gv->SAFENAME;
    if ($stash eq 'main' && $name =~ /^::/) {
        $stash = '::';
    }
    elsif (($stash eq 'main'
            && ($globalnames{$name} || $name =~ /^[^A-Za-z_:]/))
        or ($stash eq $self->{'curstash'} && !$globalnames{$name}
            && ($stash eq 'main' || $name !~ /::/))
          )
    {
        $stash = "";
    } else {
        $stash = $stash . "::";
    }
    if (!$raw and $name =~ /^(\^..|{)/) {
        $name = "{$name}";       # ${^WARNING_BITS}, etc and ${
    }
    return $stash . $name;
}

# Return the name to use for a stash variable.
# If a lexical with the same name is in scope, or
# if strictures are enabled, it may need to be
# fully-qualified.
sub stash_variable {
    my ($self, $prefix, $name, $cx) = @_;

    return $prefix.$self->maybe_qualify($prefix, $name) if $name =~ /::/;

    unless ($prefix eq '$' || $prefix eq '@' || $prefix eq '&' || #'
            $prefix eq '%' || $prefix eq '$#') {
        return "$prefix$name";
    }

    if ($name =~ /^[^[:alpha:]_+-]$/) {
      if (defined $cx && $cx == 26) {
        if ($prefix eq '@') {
            return "$prefix\{$name}";
        }
        elsif ($name eq '#') { return '${#}' } #  "${#}a" vs "$#a"
      }
      if ($prefix eq '$#') {
        return "\$#{$name}";
      }
    }

    return $prefix . $self->maybe_qualify($prefix, $name);
}

my %unctrl = # portable to EBCDIC
    (
     "\c@" => '@',      # unused
     "\cA" => 'A',
     "\cB" => 'B',
     "\cC" => 'C',
     "\cD" => 'D',
     "\cE" => 'E',
     "\cF" => 'F',
     "\cG" => 'G',
     "\cH" => 'H',
     "\cI" => 'I',
     "\cJ" => 'J',
     "\cK" => 'K',
     "\cL" => 'L',
     "\cM" => 'M',
     "\cN" => 'N',
     "\cO" => 'O',
     "\cP" => 'P',
     "\cQ" => 'Q',
     "\cR" => 'R',
     "\cS" => 'S',
     "\cT" => 'T',
     "\cU" => 'U',
     "\cV" => 'V',
     "\cW" => 'W',
     "\cX" => 'X',
     "\cY" => 'Y',
     "\cZ" => 'Z',
     "\c[" => '[',      # unused
     "\c\\" => '\\',    # unused
     "\c]" => ']',      # unused
     "\c_" => '_',      # unused
    );

# Return just the name, without the prefix.  It may be returned as a quoted
# string.  The second return value is a boolean indicating that.
sub stash_variable_name {
    my($self, $prefix, $gv) = @_;
    my $name = $self->gv_name($gv, 1);
    $name = $self->maybe_qualify($prefix,$name);
    if ($name =~ /^(?:\S|(?!\d)[\ca-\cz]?(?:\w|::)*|\d+)\z/) {
        $name =~ s/^([\ca-\cz])/'^' . $unctrl{$1}/e;
        $name =~ /^(\^..|{)/ and $name = "{$name}";
        return $name, 0; # not quoted
    }
    else {
        single_delim("q", "'", $name, $self), 1;
    }
}

sub maybe_qualify {
    my ($self,$prefix,$name) = @_;
    my $v = ($prefix eq '$#' ? '@' : $prefix) . $name;
    if ($prefix eq "") {
        $name .= "::" if $name =~ /(?:\ACORE::[^:]*|::)\z/;
        return $name;
    }
    return $name if $name =~ /::/;
    return $self->{'curstash'}.'::'. $name
        if
            $name =~ /^(?!\d)\w/         # alphabetic
         && $v    !~ /^\$[ab]\z/         # not $a or $b
         && $v =~ /\A[\$\@\%\&]/         # scalar, array, hash, or sub
         && !$globalnames{$name}         # not a global name
         && $self->{hints} & $strict_bits{vars}  # strict vars
         && !$self->lex_in_scope($v,1)   # no "our"
      or $self->lex_in_scope($v);        # conflicts with "my" variable
    return $name;
}

sub lex_in_scope {
    my ($self, $name, $our) = @_;
    substr $name, 0, 0, = $our ? 'o' : 'm'; # our/my
    $self->populate_curcvlex() if !defined $self->{'curcvlex'};

    return 0 if !defined($self->{'curcop'});
    my $seq = $self->{'curcop'}->cop_seq;
    return 0 if !exists $self->{'curcvlex'}{$name};
    for my $a (@{$self->{'curcvlex'}{$name}}) {
        my ($st, $en) = @$a;
        return 1 if $seq > $st && $seq <= $en;
    }
    return 0;
}

sub populate_curcvlex {
    my $self = shift;
    for (my $cv = $self->{'curcv'}; class($cv) eq "CV"; $cv = $cv->OUTSIDE) {
        my $padlist = $cv->PADLIST;
        # an undef CV still in lexical chain
        next if class($padlist) eq "SPECIAL";
        my @padlist = $padlist->ARRAY;
        my @ns = $padlist[0]->ARRAY;

        for (my $i=0; $i<@ns; ++$i) {
            next if class($ns[$i]) eq "SPECIAL";
            if (class($ns[$i]) eq "PV") {
                # Probably that pesky lexical @_
                next;
            }
            my $name = $ns[$i]->PVX;
            next unless defined $name;
            my ($seq_st, $seq_en) =
                ($ns[$i]->FLAGS & SVf_FAKE)
                    ? (0, 999999)
                    : ($ns[$i]->COP_SEQ_RANGE_LOW, $ns[$i]->COP_SEQ_RANGE_HIGH);

            push @{$self->{'curcvlex'}{
                        ($ns[$i]->FLAGS & SVpad_OUR ? 'o' : 'm') . $name
                  }}, [$seq_st, $seq_en, $ns[$i]];
        }
    }
}

sub find_scope_st { ((find_scope(@_))[0]); }
sub find_scope_en { ((find_scope(@_))[1]); }

# Recurses down the tree, looking for pad variable introductions and COPs
sub find_scope {
    my ($self, $op, $scope_st, $scope_en) = @_;
    carp("Undefined op in find_scope") if !defined $op;
    return ($scope_st, $scope_en) unless $op->flags & OPf_KIDS;

    my @queue = ($op);
    while(my $op = shift @queue ) {
        for (my $o=$op->first; $$o; $o=$o->sibling) {
            if ($o->name =~ /^pad.v$/ && $o->private & OPpLVAL_INTRO) {
                my $s = int($self->padname_sv($o->targ)->COP_SEQ_RANGE_LOW);
                my $e = $self->padname_sv($o->targ)->COP_SEQ_RANGE_HIGH;
                $scope_st = $s if !defined($scope_st) || $s < $scope_st;
                $scope_en = $e if !defined($scope_en) || $e > $scope_en;
                return ($scope_st, $scope_en);
            }
            elsif (is_state($o)) {
                my $c = $o->cop_seq;
                $scope_st = $c if !defined($scope_st) || $c < $scope_st;
                $scope_en = $c if !defined($scope_en) || $c > $scope_en;
                return ($scope_st, $scope_en);
            }
            elsif ($o->flags & OPf_KIDS) {
                unshift (@queue, $o);
            }
        }
    }

    return ($scope_st, $scope_en);
}

# Returns a list of subs which should be inserted before the COP
sub cop_subs {
    my ($self, $op, $out_seq) = @_;
    my $seq = $op->cop_seq;
    $seq = $out_seq if defined($out_seq) && $out_seq < $seq;
    return $self->seq_subs($seq);
}

sub seq_subs {
    my ($self, $seq) = @_;
    my @text;
#push @text, "# ($seq)\n";

    return "" if !defined $seq;
    my @pending;
    while (scalar(@{$self->{'subs_todo'}})
           and $seq > $self->{'subs_todo'}[0][0]) {
        my $cv = $self->{'subs_todo'}[0][1];
        # Skip the OUTSIDE check for lexical subs.  We may be deparsing a
        # cloned anon sub with lexical subs declared in it, in which case
        # the OUTSIDE pointer points to the anon protosub.
        my $lexical = ref $self->{'subs_todo'}[0][3];
        my $outside = !$lexical && $cv && $cv->OUTSIDE;
        if (!$lexical and $cv
         and ${$cv->OUTSIDE || \0} != ${$self->{'curcv'}})
        {
            push @pending, shift @{$self->{'subs_todo'}};
            next;
        }
        push @text, $self->next_todo;
    }
    unshift @{$self->{'subs_todo'}}, @pending;
    return @text;
}

sub _features_from_bundle {
    my ($hints, $hh) = @_;
    foreach (@{$feature::feature_bundle{@feature::hint_bundles[$hints >> $feature::hint_shift]}}) {
        $hh->{$feature::feature{$_}} = 1;
    }
    return $hh;
}

# generate any pragmas, 'package foo' etc needed to synchronise
# with the given cop

sub pragmata {
    my $self = shift;
    my($op) = @_;

    my @text;

    my $stash = $op->stashpv;
    if ($stash ne $self->{'curstash'}) {
        push @text, $self->keyword("package") . " $stash;\n";
        $self->{'curstash'} = $stash;
    }

    if (OPpCONST_ARYBASE && $self->{'arybase'} != $op->arybase) {
        push @text, '$[ = '. $op->arybase .";\n";
        $self->{'arybase'} = $op->arybase;
    }

    my $warnings = $op->warnings;
    my $warning_bits;
    if ($warnings->isa("B::SPECIAL") && $$warnings == 4) {
        $warning_bits = $warnings::Bits{"all"} & WARN_MASK;
    }
    elsif ($warnings->isa("B::SPECIAL") && $$warnings == 5) {
        $warning_bits = $warnings::NONE;
    }
    elsif ($warnings->isa("B::SPECIAL")) {
        $warning_bits = undef;
    }
    else {
        $warning_bits = $warnings->PV & WARN_MASK;
    }

    if (defined ($warning_bits) and
       !defined($self->{warnings}) || $self->{'warnings'} ne $warning_bits) {
        push @text,
            $self->declare_warnings($self->{'warnings'}, $warning_bits);
        $self->{'warnings'} = $warning_bits;
    }

    my $hints = $op->hints;
    my $old_hints = $self->{'hints'};
    if ($self->{'hints'} != $hints) {
        push @text, $self->declare_hints($self->{'hints'}, $hints);
        $self->{'hints'} = $hints;
    }

    my $newhh;
    $newhh = $op->hints_hash->HASH;

    {
        # feature bundle hints
        my $from = $old_hints & $feature::hint_mask;
        my $to   = $    hints & $feature::hint_mask;
        if ($from != $to) {
            if ($to == $feature::hint_mask) {
                if ($self->{'hinthash'}) {
                    delete $self->{'hinthash'}{$_}
                        for grep /^feature_/, keys %{$self->{'hinthash'}};
                }
                else { $self->{'hinthash'} = {} }
                $self->{'hinthash'}
                    = _features_from_bundle($from, $self->{'hinthash'});
            }
            else {
                my $bundle =
                    $feature::hint_bundles[$to >> $feature::hint_shift];
                $bundle =~ s/(\d[13579])\z/$1+1/e; # 5.11 => 5.12
                push @text,
                    $self->keyword("no") . " feature ':all';\n",
                    $self->keyword("use") . " feature ':$bundle';\n";
            }
        }
    }

    {
        push @text, $self->declare_hinthash(
            $self->{'hinthash'}, $newhh,
            $self->{indent_size}, $self->{hints},
        );
        $self->{'hinthash'} = $newhh;
    }

    return join("", @text);
}


# Notice how subs and formats are inserted between statements here;
# also $[ assignments and pragmas.
sub pp_nextstate {
    my $self = shift;
    my($op, $cx) = @_;
    $self->{'curcop'} = $op;

    my @text;

    my @subs = $self->cop_subs($op);
    if (@subs) {
        # Special marker to swallow up the semicolon
        push @subs, "\cK";
    }
    push @text, @subs;

    push @text, $self->pragmata($op);


    # This should go after of any branches that add statements, to
    # increase the chances that it refers to the same line it did in
    # the original program.
    if ($self->{'linenums'} && $cx != .5) { # $cx == .5 means in a format
        push @text, "\f#line " . $op->line .
          ' "' . $op->file, qq'"\n';
    }

    push @text, $op->label . ": " if $op->label;

    return join("", @text);
}

sub declare_warnings {
    my ($self, $from, $to) = @_;
    $from //= '';
    my $all = (warnings::bits("all") & WARN_MASK);
    unless ((($from & WARN_MASK) & ~$all) =~ /[^\0]/) {
        # no FATAL bits need turning off
        if (   ($to & WARN_MASK) eq $all) {
            return $self->keyword("use") . " warnings;\n";
        }
        elsif (($to & WARN_MASK) eq ("\0"x length($to) & WARN_MASK)) {
            return $self->keyword("no") . " warnings;\n";
        }
    }

    return "BEGIN {\${^WARNING_BITS} = \""
           . join("", map { sprintf("\\x%02x", ord $_) } split "", $to)
           . "\"}\n\cK";
}

sub declare_hints {
    my ($self, $from, $to) = @_;
    my $use = $to   & ~$from;
    my $no  = $from & ~$to;
    my $decls = "";
    for my $pragma (hint_pragmas($use)) {
        $decls .= $self->keyword("use") . " $pragma;\n";
    }
    for my $pragma (hint_pragmas($no)) {
        $decls .= $self->keyword("no") . " $pragma;\n";
    }
    return $decls;
}

# Internal implementation hints that the core sets automatically, so don't need
# (or want) to be passed back to the user
my %ignored_hints = (
    'open<' => 1,
    'open>' => 1,
    ':'     => 1,
    'strict/refs' => 1,
    'strict/subs' => 1,
    'strict/vars' => 1,
);

my %rev_feature;

sub declare_hinthash {
    my ($self, $from, $to, $indent, $hints) = @_;
    my $doing_features =
        ($hints & $feature::hint_mask) == $feature::hint_mask;
    my @decls;
    my @features;
    my @unfeatures; # bugs?
    for my $key (sort keys %$to) {
        next if $ignored_hints{$key};
        my $is_feature = $key =~ /^feature_/;
        next if $is_feature and not $doing_features;
        if (!exists $from->{$key} or $from->{$key} ne $to->{$key}) {
            push(@features, $key), next if $is_feature;
            push @decls,
                qq(\$^H{) . single_delim("q", "'", $key, $self) . qq(} = )
              . (
                   defined $to->{$key}
                        ? single_delim("q", "'", $to->{$key}, $self)
                        : 'undef'
                )
              . qq(;);
        }
    }
    for my $key (sort keys %$from) {
        next if $ignored_hints{$key};
        my $is_feature = $key =~ /^feature_/;
        next if $is_feature and not $doing_features;
        if (!exists $to->{$key}) {
            push(@unfeatures, $key), next if $is_feature;
            push @decls, qq(delete \$^H{'$key'};);
        }
    }
    my @ret;
    if (@features || @unfeatures) {
        if (!%rev_feature) { %rev_feature = reverse %feature::feature }
    }
    if (@features) {
        push @ret, $self->keyword("use") . " feature "
                 . join(", ", map "'$rev_feature{$_}'", @features) . ";\n";
    }
    if (@unfeatures) {
        push @ret, $self->keyword("no") . " feature "
                 . join(", ", map "'$rev_feature{$_}'", @unfeatures)
                 . ";\n";
    }
    @decls and
        push @ret,
             join("\n" . (" " x $indent), "BEGIN {", @decls) . "\n}\n\cK";
    return @ret;
}

sub hint_pragmas {
    my ($bits) = @_;
    my (@pragmas, @strict);
    push @pragmas, "integer" if $bits & 0x1;
    for (sort keys %strict_bits) {
        push @strict, "'$_'" if $bits & $strict_bits{$_};
    }
    if (@strict == keys %strict_bits) {
        push @pragmas, "strict";
    }
    elsif (@strict) {
        push @pragmas, "strict " . join ', ', @strict;
    }
    push @pragmas, "bytes" if $bits & 0x8;
    return @pragmas;
}

sub pp_dbstate { pp_nextstate(@_) }
sub pp_setstate { pp_nextstate(@_) }

sub pp_unstack { return "" } # see also leaveloop

my %feature_keywords = (
  # keyword => 'feature',
    state   => 'state',
    say     => 'say',
    given   => 'switch',
    when    => 'switch',
    default => 'switch',
    break   => 'switch',
    evalbytes=>'evalbytes',
    __SUB__ => '__SUB__',
   fc       => 'fc',
);

# keywords that are strong and also have a prototype
#
my %strong_proto_keywords = map { $_ => 1 } qw(
    pos
    prototype
    scalar
    study
    undef
);

sub feature_enabled {
        my($self,$name) = @_;
        my $hh;
        my $hints = $self->{hints} & $feature::hint_mask;
        if ($hints && $hints != $feature::hint_mask) {
            $hh = _features_from_bundle($hints);
        }
        elsif ($hints) { $hh = $self->{'hinthash'} }
        return $hh && $hh->{"feature_$feature_keywords{$name}"}
}

sub keyword {
    my $self = shift;
    my $name = shift;
    return $name if $name =~ /^CORE::/; # just in case
    if (exists $feature_keywords{$name}) {
        return "CORE::$name" if not $self->feature_enabled($name);
    }
    # This sub may be called for a program that has no nextstate ops.  In
    # that case we may have a lexical sub named no/use/sub in scope but
    # but $self->lex_in_scope will return false because it depends on the
    # current nextstate op.  So we need this alternate method if there is
    # no current cop.
    if (!$self->{'curcop'}) {
        $self->populate_curcvlex() if !defined $self->{'curcvlex'};
        return "CORE::$name" if exists $self->{'curcvlex'}{"m&$name"}
                             || exists $self->{'curcvlex'}{"o&$name"};
    } elsif ($self->lex_in_scope("&$name")
          || $self->lex_in_scope("&$name", 1)) {
        return "CORE::$name";
    }
    if ($strong_proto_keywords{$name}
        || ($name !~ /^(?:chom?p|do|exec|glob|s(?:elect|ystem))\z/
            && !defined eval{prototype "CORE::$name"})
    ) { return $name }
    if (
        exists $self->{subs_declared}{$name}
         or
        exists &{"$self->{curstash}::$name"}
    ) {
        return "CORE::$name"
    }
    return $name;
}

sub baseop {
    my $self = shift;
    my($op, $cx, $name) = @_;
    return $self->keyword($name);
}

sub pp_stub { "()" }
sub pp_wantarray { baseop(@_, "wantarray") }
sub pp_fork { baseop(@_, "fork") }
sub pp_wait { maybe_targmy(@_, \&baseop, "wait") }
sub pp_getppid { maybe_targmy(@_, \&baseop, "getppid") }
sub pp_time { maybe_targmy(@_, \&baseop, "time") }
sub pp_tms { baseop(@_, "times") }
sub pp_ghostent { baseop(@_, "gethostent") }
sub pp_gnetent { baseop(@_, "getnetent") }
sub pp_gprotoent { baseop(@_, "getprotoent") }
sub pp_gservent { baseop(@_, "getservent") }
sub pp_ehostent { baseop(@_, "endhostent") }
sub pp_enetent { baseop(@_, "endnetent") }
sub pp_eprotoent { baseop(@_, "endprotoent") }
sub pp_eservent { baseop(@_, "endservent") }
sub pp_gpwent { baseop(@_, "getpwent") }
sub pp_spwent { baseop(@_, "setpwent") }
sub pp_epwent { baseop(@_, "endpwent") }
sub pp_ggrent { baseop(@_, "getgrent") }
sub pp_sgrent { baseop(@_, "setgrent") }
sub pp_egrent { baseop(@_, "endgrent") }
sub pp_getlogin { baseop(@_, "getlogin") }

sub POSTFIX () { 1 }

# I couldn't think of a good short name, but this is the category of
# symbolic unary operators with interesting precedence

sub pfixop {
    my $self = shift;
    my($op, $cx, $name, $prec, $flags) = (@_, 0);
    my $kid = $op->first;
    $kid = $self->deparse($kid, $prec);
    return $self->maybe_parens(($flags & POSTFIX)
                                 ? "$kid$name"
                                   # avoid confusion with filetests
                                 : $name eq '-'
                                   && $kid =~ /^[a-zA-Z](?!\w)/
                                        ? "$name($kid)"
                                        : "$name$kid",
                               $cx, $prec);
}

sub pp_preinc { pfixop(@_, "++", 23) }
sub pp_predec { pfixop(@_, "--", 23) }
sub pp_postinc { maybe_targmy(@_, \&pfixop, "++", 23, POSTFIX) }
sub pp_postdec { maybe_targmy(@_, \&pfixop, "--", 23, POSTFIX) }
sub pp_i_preinc { pfixop(@_, "++", 23) }
sub pp_i_predec { pfixop(@_, "--", 23) }
sub pp_i_postinc { maybe_targmy(@_, \&pfixop, "++", 23, POSTFIX) }
sub pp_i_postdec { maybe_targmy(@_, \&pfixop, "--", 23, POSTFIX) }
sub pp_complement { maybe_targmy(@_, \&pfixop, "~", 21) }
*pp_ncomplement = *pp_complement;
sub pp_scomplement { maybe_targmy(@_, \&pfixop, "~.", 21) }

sub pp_negate { maybe_targmy(@_, \&real_negate) }
sub real_negate {
    my $self = shift;
    my($op, $cx) = @_;
    if ($op->first->name =~ /^(i_)?negate$/) {
        # avoid --$x
        $self->pfixop($op, $cx, "-", 21.5);
    } else {
        $self->pfixop($op, $cx, "-", 21);       
    }
}
sub pp_i_negate { pp_negate(@_) }

sub pp_not {
    my $self = shift;
    my($op, $cx) = @_;
    if ($cx <= 4) {
        $self->listop($op, $cx, "not", $op->first);
    } else {
        $self->pfixop($op, $cx, "!", 21);       
    }
}

sub unop {
    my $self = shift;
    my($op, $cx, $name, $nollafr) = @_;
    my $kid;
    if ($op->flags & OPf_KIDS) {
        $kid = $op->first;
        if (not $name) {
            # this deals with 'boolkeys' right now
            return $self->deparse($kid,$cx);
        }
        my $builtinname = $name;
        $builtinname =~ /^CORE::/ or $builtinname = "CORE::$name";
        if (defined prototype($builtinname)
           && $builtinname ne 'CORE::readline'
           && prototype($builtinname) =~ /^;?\*/
           && $kid->name eq "rv2gv") {
            $kid = $kid->first;
        }

        if ($nollafr) {
            if (($kid = $self->deparse($kid, 16)) !~ s/^\cS//) {
                # require foo() is a syntax error.
                $kid =~ /^(?!\d)\w/ and $kid = "($kid)";
            }
            return $self->maybe_parens(
                        $self->keyword($name) . " $kid", $cx, 16
                   );
        }   
        return $self->maybe_parens_unop($name, $kid, $cx);
    } else {
        return $self->maybe_parens(
            $self->keyword($name) . ($op->flags & OPf_SPECIAL ? "()" : ""),
            $cx, 16,
        );
    }
}

sub pp_chop { maybe_targmy(@_, \&unop, "chop") }
sub pp_chomp { maybe_targmy(@_, \&unop, "chomp") }
sub pp_schop { maybe_targmy(@_, \&unop, "chop") }
sub pp_schomp { maybe_targmy(@_, \&unop, "chomp") }
sub pp_defined { unop(@_, "defined") }
sub pp_undef { unop(@_, "undef") }
sub pp_study { unop(@_, "study") }
sub pp_ref { unop(@_, "ref") }
sub pp_pos { maybe_local(@_, unop(@_, "pos")) }

sub pp_sin { maybe_targmy(@_, \&unop, "sin") }
sub pp_cos { maybe_targmy(@_, \&unop, "cos") }
sub pp_rand { maybe_targmy(@_, \&unop, "rand") }
sub pp_srand { unop(@_, "srand") }
sub pp_exp { maybe_targmy(@_, \&unop, "exp") }
sub pp_log { maybe_targmy(@_, \&unop, "log") }
sub pp_sqrt { maybe_targmy(@_, \&unop, "sqrt") }
sub pp_int { maybe_targmy(@_, \&unop, "int") }
sub pp_hex { maybe_targmy(@_, \&unop, "hex") }
sub pp_oct { maybe_targmy(@_, \&unop, "oct") }
sub pp_abs { maybe_targmy(@_, \&unop, "abs") }

sub pp_length { maybe_targmy(@_, \&unop, "length") }
sub pp_ord { maybe_targmy(@_, \&unop, "ord") }
sub pp_chr { maybe_targmy(@_, \&unop, "chr") }

sub pp_each { unop(@_, "each") }
sub pp_values { unop(@_, "values") }
sub pp_keys { unop(@_, "keys") }
{ no strict 'refs'; *{"pp_r$_"} = *{"pp_$_"} for qw< keys each values >; }
sub pp_boolkeys { 
    # no name because its an optimisation op that has no keyword
    unop(@_,"");
}
sub pp_aeach { unop(@_, "each") }
sub pp_avalues { unop(@_, "values") }
sub pp_akeys { unop(@_, "keys") }
sub pp_pop { unop(@_, "pop") }
sub pp_shift { unop(@_, "shift") }

sub pp_caller { unop(@_, "caller") }
sub pp_reset { unop(@_, "reset") }
sub pp_exit { unop(@_, "exit") }
sub pp_prototype { unop(@_, "prototype") }

sub pp_close { unop(@_, "close") }
sub pp_fileno { unop(@_, "fileno") }
sub pp_umask { unop(@_, "umask") }
sub pp_untie { unop(@_, "untie") }
sub pp_tied { unop(@_, "tied") }
sub pp_dbmclose { unop(@_, "dbmclose") }
sub pp_getc { unop(@_, "getc") }
sub pp_eof { unop(@_, "eof") }
sub pp_tell { unop(@_, "tell") }
sub pp_getsockname { unop(@_, "getsockname") }
sub pp_getpeername { unop(@_, "getpeername") }

sub pp_chdir {
    my ($self, $op, $cx) = @_;
    if (($op->flags & (OPf_SPECIAL|OPf_KIDS)) == (OPf_SPECIAL|OPf_KIDS)) {
        my $kw = $self->keyword("chdir");
        my $kid = $self->const_sv($op->first)->PV;
        my $code = $kw
                 . ($cx >= 16 || $self->{'parens'} ? "($kid)" : " $kid");
        maybe_targmy(@_, sub { $_[3] }, $code);
    } else {
        maybe_targmy(@_, \&unop, "chdir")
    }
}

sub pp_chroot { maybe_targmy(@_, \&unop, "chroot") }
sub pp_readlink { unop(@_, "readlink") }
sub pp_rmdir { maybe_targmy(@_, \&unop, "rmdir") }
sub pp_readdir { unop(@_, "readdir") }
sub pp_telldir { unop(@_, "telldir") }
sub pp_rewinddir { unop(@_, "rewinddir") }
sub pp_closedir { unop(@_, "closedir") }
sub pp_getpgrp { maybe_targmy(@_, \&unop, "getpgrp") }
sub pp_localtime { unop(@_, "localtime") }
sub pp_gmtime { unop(@_, "gmtime") }
sub pp_alarm { unop(@_, "alarm") }
sub pp_sleep { maybe_targmy(@_, \&unop, "sleep") }

sub pp_dofile {
    my $code = unop(@_, "do", 1); # llafr does not apply
    if ($code =~ s/^((?:CORE::)?do) \{/$1({/) { $code .= ')' }
    $code;
}
sub pp_entereval {
    unop(
      @_,
      $_[1]->private & OPpEVAL_BYTES ? 'evalbytes' : "eval"
    )
}

sub pp_ghbyname { unop(@_, "gethostbyname") }
sub pp_gnbyname { unop(@_, "getnetbyname") }
sub pp_gpbyname { unop(@_, "getprotobyname") }
sub pp_shostent { unop(@_, "sethostent") }
sub pp_snetent { unop(@_, "setnetent") }
sub pp_sprotoent { unop(@_, "setprotoent") }
sub pp_sservent { unop(@_, "setservent") }
sub pp_gpwnam { unop(@_, "getpwnam") }
sub pp_gpwuid { unop(@_, "getpwuid") }
sub pp_ggrnam { unop(@_, "getgrnam") }
sub pp_ggrgid { unop(@_, "getgrgid") }

sub pp_lock { unop(@_, "lock") }

sub pp_continue { unop(@_, "continue"); }
sub pp_break { unop(@_, "break"); }

sub givwhen {
    my $self = shift;
    my($op, $cx, $givwhen) = @_;

    my $enterop = $op->first;
    my ($head, $block);
    if ($enterop->flags & OPf_SPECIAL) {
        $head = $self->keyword("default");
        $block = $self->deparse($enterop->first, 0);
    }
    else {
        my $cond = $enterop->first;
        my $cond_str = $self->deparse($cond, 1);
        $head = "$givwhen ($cond_str)";
        $block = $self->deparse($cond->sibling, 0);
    }

    return "$head {\n".
        "\t$block\n".
        "\b}\cK";
}

sub pp_leavegiven { givwhen(@_, $_[0]->keyword("given")); }
sub pp_leavewhen  { givwhen(@_, $_[0]->keyword("when")); }

sub pp_exists {
    my $self = shift;
    my($op, $cx) = @_;
    my $arg;
    my $name = $self->keyword("exists");
    if ($op->private & OPpEXISTS_SUB) {
        # Checking for the existence of a subroutine
        return $self->maybe_parens_func($name,
                                $self->pp_rv2cv($op->first, 16), $cx, 16);
    }
    if ($op->flags & OPf_SPECIAL) {
        # Array element, not hash element
        return $self->maybe_parens_func($name,
                                $self->pp_aelem($op->first, 16), $cx, 16);
    }
    return $self->maybe_parens_func($name, $self->pp_helem($op->first, 16),
                                    $cx, 16);
}

sub pp_delete {
    my $self = shift;
    my($op, $cx) = @_;
    my $arg;
    my $name = $self->keyword("delete");
    if ($op->private & (OPpSLICE|OPpKVSLICE)) {
        if ($op->flags & OPf_SPECIAL) {
            # Deleting from an array, not a hash
            return $self->maybe_parens_func($name,
                                        $self->pp_aslice($op->first, 16),
                                        $cx, 16);
        }
        return $self->maybe_parens_func($name,
                                        $self->pp_hslice($op->first, 16),
                                        $cx, 16);
    } else {
        if ($op->flags & OPf_SPECIAL) {
            # Deleting from an array, not a hash
            return $self->maybe_parens_func($name,
                                        $self->pp_aelem($op->first, 16),
                                        $cx, 16);
        }
        return $self->maybe_parens_func($name,
                                        $self->pp_helem($op->first, 16),
                                        $cx, 16);
    }
}

sub pp_require {
    my $self = shift;
    my($op, $cx) = @_;
    my $opname = $op->flags & OPf_SPECIAL ? 'CORE::require' : 'require';
    my $kid = $op->first;
    if ($kid->name eq 'const') {
        my $priv = $kid->private;
        my $sv = $self->const_sv($kid);
        my $arg;
        if ($priv & OPpCONST_BARE) {
            $arg = $sv->PV;
            $arg =~ s[/][::]g;
            $arg =~ s/\.pm//g;
        } elsif ($priv & OPpCONST_NOVER) {
            $opname = $self->keyword('no');
            $arg = $self->const($sv, 16);
        } elsif ((my $tmp = $self->const($sv, 16)) =~ /^v/) {
            $arg = $tmp;
        }
        if ($arg) {
            return $self->maybe_parens("$opname $arg", $cx, 16);
        }
    }
    $self->unop(
            $op, $cx,
            $opname,
            1, # llafr does not apply
    );
}

sub pp_scalar {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first;
    if (not null $kid->sibling) {
        # XXX Was a here-doc
        return $self->dquote($op);
    }
    $self->unop(@_, "scalar");
}


sub padval {
    my $self = shift;
    my $targ = shift;
    return $self->{'curcv'}->PADLIST->ARRAYelt(1)->ARRAYelt($targ);
}

sub anon_hash_or_list {
    my $self = shift;
    my($op, $cx) = @_;

    my($pre, $post) = @{{"anonlist" => ["[","]"],
                         "anonhash" => ["{","}"]}->{$op->name}};
    my($expr, @exprs);
    $op = $op->first->sibling; # skip pushmark
    for (; !null($op); $op = $op->sibling) {
        $expr = $self->deparse($op, 6);
        push @exprs, $expr;
    }
    if ($pre eq "{" and $cx < 1) {
        # Disambiguate that it's not a block
        $pre = "+{";
    }
    return $pre . join(", ", @exprs) . $post;
}

sub pp_anonlist {
    my $self = shift;
    my ($op, $cx) = @_;
    if ($op->flags & OPf_SPECIAL) {
        return $self->anon_hash_or_list($op, $cx);
    }
    warn "Unexpected op pp_" . $op->name() . " without OPf_SPECIAL";
    return 'XXX';
}

*pp_anonhash = \&pp_anonlist;

sub pp_refgen {
    my $self = shift;   
    my($op, $cx) = @_;
    my $kid = $op->first;
    if ($kid->name eq "null") {
        my $anoncode = $kid = $kid->first;
        if ($anoncode->name eq "anonconst") {
            $anoncode = $anoncode->first->first->sibling;
        }
        if ($anoncode->name eq "anoncode"
         or !null($anoncode = $kid->sibling) and
                 $anoncode->name eq "anoncode") {
            return $self->e_anoncode({ code => $self->padval($anoncode->targ) });
        } elsif ($kid->name eq "pushmark") {
            my $sib_name = $kid->sibling->name;
            if ($sib_name eq 'entersub') {
                my $text = $self->deparse($kid->sibling, 1);
                # Always show parens for \(&func()), but only with -p otherwise
                $text = "($text)" if $self->{'parens'}
                                 or $kid->sibling->private & OPpENTERSUB_AMPER;
                return "\\$text";
            }
        }
    }
    local $self->{'in_refgen'} = 1;
    $self->pfixop($op, $cx, "\\", 20);
}

sub e_anoncode {
    my ($self, $info) = @_;
    my $text = $self->deparse_sub($info->{code});
    return $self->keyword("sub") . " $text";
}

sub pp_srefgen { pp_refgen(@_) }

sub pp_readline {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first;
    if (is_scalar($kid)
        and $op->flags & OPf_SPECIAL
        and $self->deparse($kid, 1) eq 'ARGV')
    {
        return '<<>>';
    }
    return $self->unop($op, $cx, "readline");
}

sub pp_rcatline {
    my $self = shift;
    my($op) = @_;
    return "<" . $self->gv_name($self->gv_or_padgv($op)) . ">";
}

# Unary operators that can occur as pseudo-listops inside double quotes
sub dq_unop {
    my $self = shift;
    my($op, $cx, $name, $prec, $flags) = (@_, 0, 0);
    my $kid;
    if ($op->flags & OPf_KIDS) {
       $kid = $op->first;
       # If there's more than one kid, the first is an ex-pushmark.
       $kid = $kid->sibling if not null $kid->sibling;
       return $self->maybe_parens_unop($name, $kid, $cx);
    } else {
       return $name .  ($op->flags & OPf_SPECIAL ? "()" : "");
    }
}

sub pp_ucfirst { dq_unop(@_, "ucfirst") }
sub pp_lcfirst { dq_unop(@_, "lcfirst") }
sub pp_uc { dq_unop(@_, "uc") }
sub pp_lc { dq_unop(@_, "lc") }
sub pp_quotemeta { maybe_targmy(@_, \&dq_unop, "quotemeta") }
sub pp_fc { dq_unop(@_, "fc") }

sub loopex {
    my $self = shift;
    my ($op, $cx, $name) = @_;
    if (class($op) eq "PVOP") {
        $name .= " " . $op->pv;
    } elsif (class($op) eq "OP") {
        # no-op
    } elsif (class($op) eq "UNOP") {
        (my $kid = $self->deparse($op->first, 7)) =~ s/^\cS//;
        # last foo() is a syntax error.
        $kid =~ /^(?!\d)\w/ and $kid = "($kid)";
        $name .= " $kid";
    }
    return $self->maybe_parens($name, $cx, 7);
}

sub pp_last { loopex(@_, "last") }
sub pp_next { loopex(@_, "next") }
sub pp_redo { loopex(@_, "redo") }
sub pp_goto { loopex(@_, "goto") }
sub pp_dump { loopex(@_, "CORE::dump") }

sub ftst {
    my $self = shift;
    my($op, $cx, $name) = @_;
    if (class($op) eq "UNOP") {
        # Genuine '-X' filetests are exempt from the LLAFR, but not
        # l?stat()
        if ($name =~ /^-/) {
            (my $kid = $self->deparse($op->first, 16)) =~ s/^\cS//;
            return $self->maybe_parens("$name $kid", $cx, 16);
        }
        return $self->maybe_parens_unop($name, $op->first, $cx);
    } elsif (class($op) =~ /^(SV|PAD)OP$/) {
        return $self->maybe_parens_func($name, $self->pp_gv($op, 1), $cx, 16);
    } else { # I don't think baseop filetests ever survive ck_ftst, but...
        return $name;
    }
}

sub pp_lstat    { ftst(@_, "lstat") }
sub pp_stat     { ftst(@_, "stat") }
sub pp_ftrread  { ftst(@_, "-R") }
sub pp_ftrwrite { ftst(@_, "-W") }
sub pp_ftrexec  { ftst(@_, "-X") }
sub pp_fteread  { ftst(@_, "-r") }
sub pp_ftewrite { ftst(@_, "-w") }
sub pp_fteexec  { ftst(@_, "-x") }
sub pp_ftis     { ftst(@_, "-e") }
sub pp_fteowned { ftst(@_, "-O") }
sub pp_ftrowned { ftst(@_, "-o") }
sub pp_ftzero   { ftst(@_, "-z") }
sub pp_ftsize   { ftst(@_, "-s") }
sub pp_ftmtime  { ftst(@_, "-M") }
sub pp_ftatime  { ftst(@_, "-A") }
sub pp_ftctime  { ftst(@_, "-C") }
sub pp_ftsock   { ftst(@_, "-S") }
sub pp_ftchr    { ftst(@_, "-c") }
sub pp_ftblk    { ftst(@_, "-b") }
sub pp_ftfile   { ftst(@_, "-f") }
sub pp_ftdir    { ftst(@_, "-d") }
sub pp_ftpipe   { ftst(@_, "-p") }
sub pp_ftlink   { ftst(@_, "-l") }
sub pp_ftsuid   { ftst(@_, "-u") }
sub pp_ftsgid   { ftst(@_, "-g") }
sub pp_ftsvtx   { ftst(@_, "-k") }
sub pp_fttty    { ftst(@_, "-t") }
sub pp_fttext   { ftst(@_, "-T") }
sub pp_ftbinary { ftst(@_, "-B") }

sub SWAP_CHILDREN () { 1 }
sub ASSIGN () { 2 } # has OP= variant
sub LIST_CONTEXT () { 4 } # Assignment is in list context

my(%left, %right);

sub assoc_class {
    my $op = shift;
    my $name = $op->name;
    if ($name eq "concat" and $op->first->name eq "concat") {
        # avoid spurious '=' -- see comment in pp_concat
        return "concat";
    }
    if ($name eq "null" and class($op) eq "UNOP"
        and $op->first->name =~ /^(and|x?or)$/
        and null $op->first->sibling)
    {
        # Like all conditional constructs, OP_ANDs and OP_ORs are topped
        # with a null that's used as the common end point of the two
        # flows of control. For precedence purposes, ignore it.
        # (COND_EXPRs have these too, but we don't bother with
        # their associativity).
        return assoc_class($op->first);
    }
    return $name . ($op->flags & OPf_STACKED ? "=" : "");
}

# Left associative operators, like '+', for which
# $a + $b + $c is equivalent to ($a + $b) + $c

BEGIN {
    %left = ('multiply' => 19, 'i_multiply' => 19,
             'divide' => 19, 'i_divide' => 19,
             'modulo' => 19, 'i_modulo' => 19,
             'repeat' => 19,
             'add' => 18, 'i_add' => 18,
             'subtract' => 18, 'i_subtract' => 18,
             'concat' => 18,
             'left_shift' => 17, 'right_shift' => 17,
             'bit_and' => 13, 'nbit_and' => 13, 'sbit_and' => 13,
             'bit_or' => 12, 'bit_xor' => 12,
             'sbit_or' => 12, 'sbit_xor' => 12,
             'nbit_or' => 12, 'nbit_xor' => 12,
             'and' => 3,
             'or' => 2, 'xor' => 2,
            );
}

sub deparse_binop_left {
    my $self = shift;
    my($op, $left, $prec) = @_;
    if ($left{assoc_class($op)} && $left{assoc_class($left)}
        and $left{assoc_class($op)} == $left{assoc_class($left)})
    {
        return $self->deparse($left, $prec - .00001);
    } else {
        return $self->deparse($left, $prec);    
    }
}

# Right associative operators, like '=', for which
# $a = $b = $c is equivalent to $a = ($b = $c)

BEGIN {
    %right = ('pow' => 22,
              'sassign=' => 7, 'aassign=' => 7,
              'multiply=' => 7, 'i_multiply=' => 7,
              'divide=' => 7, 'i_divide=' => 7,
              'modulo=' => 7, 'i_modulo=' => 7,
              'repeat=' => 7, 'refassign' => 7, 'refassign=' => 7,
              'add=' => 7, 'i_add=' => 7,
              'subtract=' => 7, 'i_subtract=' => 7,
              'concat=' => 7,
              'left_shift=' => 7, 'right_shift=' => 7,
              'bit_and=' => 7, 'sbit_and=' => 7, 'nbit_and=' => 7,
              'nbit_or=' => 7, 'nbit_xor=' => 7,
              'sbit_or=' => 7, 'sbit_xor=' => 7,
              'andassign' => 7,
              'orassign' => 7,
             );
}

sub deparse_binop_right {
    my $self = shift;
    my($op, $right, $prec) = @_;
    if ($right{assoc_class($op)} && $right{assoc_class($right)}
        and $right{assoc_class($op)} == $right{assoc_class($right)})
    {
        return $self->deparse($right, $prec - .00001);
    } else {
        return $self->deparse($right, $prec);   
    }
}

sub binop {
    my $self = shift;
    my ($op, $cx, $opname, $prec, $flags) = (@_, 0);
    my $left = $op->first;
    my $right = $op->last;
    my $eq = "";
    if ($op->flags & OPf_STACKED && $flags & ASSIGN) {
        $eq = "=";
        $prec = 7;
    }
    if ($flags & SWAP_CHILDREN) {
        ($left, $right) = ($right, $left);
    }
    my $leftop = $left;
    $left = $self->deparse_binop_left($op, $left, $prec);
    $left = "($left)" if $flags & LIST_CONTEXT
                     and    $left !~ /^(my|our|local|state|)\s*[\@%\(]/
                         || do {
                                # Parenthesize if the left argument is a
                                # lone repeat op.
                                my $left = $leftop->first->sibling;
                                $left->name eq 'repeat'
                                    && null($left->sibling);
                            };
    $right = $self->deparse_binop_right($op, $right, $prec);
    return $self->maybe_parens("$left $opname$eq $right", $cx, $prec);
}

sub pp_add { maybe_targmy(@_, \&binop, "+", 18, ASSIGN) }
sub pp_multiply { maybe_targmy(@_, \&binop, "*", 19, ASSIGN) }
sub pp_subtract { maybe_targmy(@_, \&binop, "-",18,  ASSIGN) }
sub pp_divide { maybe_targmy(@_, \&binop, "/", 19, ASSIGN) }
sub pp_modulo { maybe_targmy(@_, \&binop, "%", 19, ASSIGN) }
sub pp_i_add { maybe_targmy(@_, \&binop, "+", 18, ASSIGN) }
sub pp_i_multiply { maybe_targmy(@_, \&binop, "*", 19, ASSIGN) }
sub pp_i_subtract { maybe_targmy(@_, \&binop, "-", 18, ASSIGN) }
sub pp_i_divide { maybe_targmy(@_, \&binop, "/", 19, ASSIGN) }
sub pp_i_modulo { maybe_targmy(@_, \&binop, "%", 19, ASSIGN) }
sub pp_pow { maybe_targmy(@_, \&binop, "**", 22, ASSIGN) }

sub pp_left_shift { maybe_targmy(@_, \&binop, "<<", 17, ASSIGN) }
sub pp_right_shift { maybe_targmy(@_, \&binop, ">>", 17, ASSIGN) }
sub pp_bit_and { maybe_targmy(@_, \&binop, "&", 13, ASSIGN) }
sub pp_bit_or { maybe_targmy(@_, \&binop, "|", 12, ASSIGN) }
sub pp_bit_xor { maybe_targmy(@_, \&binop, "^", 12, ASSIGN) }
*pp_nbit_and = *pp_bit_and;
*pp_nbit_or  = *pp_bit_or;
*pp_nbit_xor = *pp_bit_xor;
sub pp_sbit_and { maybe_targmy(@_, \&binop, "&.", 13, ASSIGN) }
sub pp_sbit_or { maybe_targmy(@_, \&binop, "|.", 12, ASSIGN) }
sub pp_sbit_xor { maybe_targmy(@_, \&binop, "^.", 12, ASSIGN) }

sub pp_eq { binop(@_, "==", 14) }
sub pp_ne { binop(@_, "!=", 14) }
sub pp_lt { binop(@_, "<", 15) }
sub pp_gt { binop(@_, ">", 15) }
sub pp_ge { binop(@_, ">=", 15) }
sub pp_le { binop(@_, "<=", 15) }
sub pp_ncmp { binop(@_, "<=>", 14) }
sub pp_i_eq { binop(@_, "==", 14) }
sub pp_i_ne { binop(@_, "!=", 14) }
sub pp_i_lt { binop(@_, "<", 15) }
sub pp_i_gt { binop(@_, ">", 15) }
sub pp_i_ge { binop(@_, ">=", 15) }
sub pp_i_le { binop(@_, "<=", 15) }
sub pp_i_ncmp { maybe_targmy(@_, \&binop, "<=>", 14) }

sub pp_seq { binop(@_, "eq", 14) }
sub pp_sne { binop(@_, "ne", 14) }
sub pp_slt { binop(@_, "lt", 15) }
sub pp_sgt { binop(@_, "gt", 15) }
sub pp_sge { binop(@_, "ge", 15) }
sub pp_sle { binop(@_, "le", 15) }
sub pp_scmp { maybe_targmy(@_, \&binop, "cmp", 14) }

sub pp_sassign { binop(@_, "=", 7, SWAP_CHILDREN) }
sub pp_aassign { binop(@_, "=", 7, SWAP_CHILDREN | LIST_CONTEXT) }

sub pp_smartmatch {
    my ($self, $op, $cx) = @_;
    if (($op->flags & OPf_SPECIAL) && $self->{expand} < 2) {
        return $self->deparse($op->last, $cx);
    }
    else {
        binop(@_, "~~", 14);
    }
}

# '.' is special because concats-of-concats are optimized to save copying
# by making all but the first concat stacked. The effect is as if the
# programmer had written '($a . $b) .= $c', except legal.
sub pp_concat { maybe_targmy(@_, \&real_concat) }
sub real_concat {
    my $self = shift;
    my($op, $cx) = @_;
    my $left = $op->first;
    my $right = $op->last;
    my $eq = "";
    my $prec = 18;
    if (($op->flags & OPf_STACKED) and !($op->private & OPpCONCAT_NESTED)) {
        # '.=' rather than optimised '.'
        $eq = "=";
        $prec = 7;
    }
    $left = $self->deparse_binop_left($op, $left, $prec);
    $right = $self->deparse_binop_right($op, $right, $prec);
    return $self->maybe_parens("$left .$eq $right", $cx, $prec);
}

sub pp_repeat { maybe_targmy(@_, \&repeat) }

# 'x' is weird when the left arg is a list
sub repeat {
    my $self = shift;
    my($op, $cx) = @_;
    my $left = $op->first;
    my $right = $op->last;
    my $eq = "";
    my $prec = 19;
    if ($op->flags & OPf_STACKED) {
        $eq = "=";
        $prec = 7;
    }
    if (null($right)) { # list repeat; count is inside left-side ex-list
                        # in 5.21.5 and earlier
        my $kid = $left->first->sibling; # skip pushmark
        my @exprs;
        for (; !null($kid->sibling); $kid = $kid->sibling) {
            push @exprs, $self->deparse($kid, 6);
        }
        $right = $kid;
        $left = "(" . join(", ", @exprs). ")";
    } else {
        my $dolist = $op->private & OPpREPEAT_DOLIST;
        $left = $self->deparse_binop_left($op, $left, $dolist ? 1 : $prec);
        if ($dolist) {
            $left = "($left)";
        }
    }
    $right = $self->deparse_binop_right($op, $right, $prec);
    return $self->maybe_parens("$left x$eq $right", $cx, $prec);
}

sub range {
    my $self = shift;
    my ($op, $cx, $type) = @_;
    my $left = $op->first;
    my $right = $left->sibling;
    $left = $self->deparse($left, 9);
    $right = $self->deparse($right, 9);
    return $self->maybe_parens("$left $type $right", $cx, 9);
}

sub pp_flop {
    my $self = shift;
    my($op, $cx) = @_;
    my $flip = $op->first;
    my $type = ($flip->flags & OPf_SPECIAL) ? "..." : "..";
    return $self->range($flip->first, $cx, $type);
}

# one-line while/until is handled in pp_leave

sub logop {
    my $self = shift;
    my ($op, $cx, $lowop, $lowprec, $highop, $highprec, $blockname) = @_;
    my $left = $op->first;
    my $right = $op->first->sibling;
    $blockname &&= $self->keyword($blockname);
    if ($cx < 1 and is_scope($right) and $blockname
        and $self->{'expand'} < 7)
    { # if ($a) {$b}
        $left = $self->deparse($left, 1);
        $right = $self->deparse($right, 0);
        return "$blockname ($left) {\n\t$right\n\b}\cK";
    } elsif ($cx < 1 and $blockname and not $self->{'parens'}
             and $self->{'expand'} < 7) { # $b if $a
        $right = $self->deparse($right, 1);
        $left = $self->deparse($left, 1);
        return "$right $blockname $left";
    } elsif ($cx > $lowprec and $highop) { # $a && $b
        $left = $self->deparse_binop_left($op, $left, $highprec);
        $right = $self->deparse_binop_right($op, $right, $highprec);
        return $self->maybe_parens("$left $highop $right", $cx, $highprec);
    } else { # $a and $b
        $left = $self->deparse_binop_left($op, $left, $lowprec);
        $right = $self->deparse_binop_right($op, $right, $lowprec);
        return $self->maybe_parens("$left $lowop $right", $cx, $lowprec);
    }
}

sub pp_and { logop(@_, "and", 3, "&&", 11, "if") }
sub pp_or  { logop(@_, "or",  2, "||", 10, "unless") }
sub pp_dor { logop(@_, "//", 10) }

# xor is syntactically a logop, but it's really a binop (contrary to
# old versions of opcode.pl). Syntax is what matters here.
sub pp_xor { logop(@_, "xor", 2, "",   0,  "") }

sub logassignop {
    my $self = shift;
    my ($op, $cx, $opname) = @_;
    my $left = $op->first;
    my $right = $op->first->sibling->first; # skip sassign
    $left = $self->deparse($left, 7);
    $right = $self->deparse($right, 7);
    return $self->maybe_parens("$left $opname $right", $cx, 7);
}

sub pp_andassign { logassignop(@_, "&&=") }
sub pp_orassign  { logassignop(@_, "||=") }
sub pp_dorassign { logassignop(@_, "//=") }

sub rv2gv_or_string {
    my($self,$op) = @_;
    if ($op->name eq "gv") { # could be open("open") or open("###")
        my($name,$quoted) =
            $self->stash_variable_name("", $self->gv_or_padgv($op));
        $quoted ? $name : "*$name";
    }
    else {
        $self->deparse($op, 6);
    }
}

sub listop {
    my $self = shift;
    my($op, $cx, $name, $kid, $nollafr) = @_;
    my(@exprs);
    my $parens = ($cx >= 5) || $self->{'parens'};
    $kid ||= $op->first->sibling;
    # If there are no arguments, add final parentheses (or parenthesize the
    # whole thing if the llafr does not apply) to account for cases like
    # (return)+1 or setpgrp()+1.  When the llafr does not apply, we use a
    # precedence of 6 (< comma), as "return, 1" does not need parentheses.
    if (null $kid) {
        return $nollafr
                ? $self->maybe_parens($self->keyword($name), $cx, 7)
                : $self->keyword($name) . '()' x (7 < $cx);
    }
    my $first;
    my $fullname = $self->keyword($name);
    my $proto = prototype("CORE::$name");
    if (
         (     (defined $proto && $proto =~ /^;?\*/)
            || $name eq 'select' # select(F) doesn't have a proto
         )
         && $kid->name eq "rv2gv"
         && !($kid->private & OPpLVAL_INTRO)
    ) {
        $first = $self->rv2gv_or_string($kid->first);
    }
    else {
        $first = $self->deparse($kid, 6);
    }
    if ($name eq "chmod" && $first =~ /^\d+$/) {
        $first = sprintf("%#o", $first);
    }
    $first = "+$first"
        if not $parens and not $nollafr and substr($first, 0, 1) eq "(";
    push @exprs, $first;
    $kid = $kid->sibling;
    if (defined $proto && $proto =~ /^\*\*/ && $kid->name eq "rv2gv"
         && !($kid->private & OPpLVAL_INTRO)) {
        push @exprs, $first = $self->rv2gv_or_string($kid->first);
        $kid = $kid->sibling;
    }
    for (; !null($kid); $kid = $kid->sibling) {
        push @exprs, $self->deparse($kid, 6);
    }
    if ($name eq "reverse" && ($op->private & OPpREVERSE_INPLACE)) {
        return "$exprs[0] = $fullname"
                 . ($parens ? "($exprs[0])" : " $exprs[0]");
    }

    if ($parens && $nollafr) {
        return "($fullname " . join(", ", @exprs) . ")";
    } elsif ($parens) {
        return "$fullname(" . join(", ", @exprs) . ")";
    } else {
        return "$fullname " . join(", ", @exprs);
    }
}

sub pp_bless { listop(@_, "bless") }
sub pp_atan2 { maybe_targmy(@_, \&listop, "atan2") }
sub pp_substr {
    my ($self,$op,$cx) = @_;
    if ($op->private & OPpSUBSTR_REPL_FIRST) {
        return
           listop($self, $op, 7, "substr", $op->first->sibling->sibling)
         . " = "
         . $self->deparse($op->first->sibling, 7);
    }
    maybe_local(@_, listop(@_, "substr"))
}

sub pp_index {
    # Also handles pp_rindex.
    #
    # The body of this function includes an unrolled maybe_targmy(),
    # since the two parts of that sub's actions need to have have the
    # '== -1' bit in between

    my($self, $op, $cx) = @_;

    my $lex  = ($op->private & OPpTARGET_MY);
    my $bool = ($op->private & OPpTRUEBOOL);

    my $val = $self->listop($op, ($bool ? 14 : $lex ? 7 : $cx), $op->name);

    # (index() == -1) has op_eq and op_const optimised away
    if ($bool) {
        $val .= ($op->private & OPpINDEX_BOOLNEG) ? " == -1" : " != -1";
        $val = "($val)" if ($op->flags & OPf_PARENS);
    }
    if ($lex) {
        my $var = $self->padname($op->targ);
        $val = $self->maybe_parens("$var = $val", $cx, 7);
    }
    $val;
}

sub pp_rindex { pp_index(@_); }
sub pp_vec { maybe_targmy(@_, \&maybe_local, listop(@_, "vec")) }
sub pp_sprintf { maybe_targmy(@_, \&listop, "sprintf") }
sub pp_formline { listop(@_, "formline") } # see also deparse_format
sub pp_crypt { maybe_targmy(@_, \&listop, "crypt") }
sub pp_unpack { listop(@_, "unpack") }
sub pp_pack { listop(@_, "pack") }
sub pp_join { maybe_targmy(@_, \&listop, "join") }
sub pp_splice { listop(@_, "splice") }
sub pp_push { maybe_targmy(@_, \&listop, "push") }
sub pp_unshift { maybe_targmy(@_, \&listop, "unshift") }
sub pp_reverse { listop(@_, "reverse") }
sub pp_warn { listop(@_, "warn") }
sub pp_die { listop(@_, "die") }
sub pp_return { listop(@_, "return", undef, 1) } # llafr does not apply
sub pp_open { listop(@_, "open") }
sub pp_pipe_op { listop(@_, "pipe") }
sub pp_tie { listop(@_, "tie") }
sub pp_binmode { listop(@_, "binmode") }
sub pp_dbmopen { listop(@_, "dbmopen") }
sub pp_sselect { listop(@_, "select") }
sub pp_select { listop(@_, "select") }
sub pp_read { listop(@_, "read") }
sub pp_sysopen { listop(@_, "sysopen") }
sub pp_sysseek { listop(@_, "sysseek") }
sub pp_sysread { listop(@_, "sysread") }
sub pp_syswrite { listop(@_, "syswrite") }
sub pp_send { listop(@_, "send") }
sub pp_recv { listop(@_, "recv") }
sub pp_seek { listop(@_, "seek") }
sub pp_fcntl { listop(@_, "fcntl") }
sub pp_ioctl { listop(@_, "ioctl") }
sub pp_flock { maybe_targmy(@_, \&listop, "flock") }
sub pp_socket { listop(@_, "socket") }
sub pp_sockpair { listop(@_, "socketpair") }
sub pp_bind { listop(@_, "bind") }
sub pp_connect { listop(@_, "connect") }
sub pp_listen { listop(@_, "listen") }
sub pp_accept { listop(@_, "accept") }
sub pp_shutdown { listop(@_, "shutdown") }
sub pp_gsockopt { listop(@_, "getsockopt") }
sub pp_ssockopt { listop(@_, "setsockopt") }
sub pp_chown { maybe_targmy(@_, \&listop, "chown") }
sub pp_unlink { maybe_targmy(@_, \&listop, "unlink") }
sub pp_chmod { maybe_targmy(@_, \&listop, "chmod") }
sub pp_utime { maybe_targmy(@_, \&listop, "utime") }
sub pp_rename { maybe_targmy(@_, \&listop, "rename") }
sub pp_link { maybe_targmy(@_, \&listop, "link") }
sub pp_symlink { maybe_targmy(@_, \&listop, "symlink") }
sub pp_mkdir { maybe_targmy(@_, \&listop, "mkdir") }
sub pp_open_dir { listop(@_, "opendir") }
sub pp_seekdir { listop(@_, "seekdir") }
sub pp_waitpid { maybe_targmy(@_, \&listop, "waitpid") }
sub pp_system { maybe_targmy(@_, \&indirop, "system") }
sub pp_exec { maybe_targmy(@_, \&indirop, "exec") }
sub pp_kill { maybe_targmy(@_, \&listop, "kill") }
sub pp_setpgrp { maybe_targmy(@_, \&listop, "setpgrp") }
sub pp_getpriority { maybe_targmy(@_, \&listop, "getpriority") }
sub pp_setpriority { maybe_targmy(@_, \&listop, "setpriority") }
sub pp_shmget { listop(@_, "shmget") }
sub pp_shmctl { listop(@_, "shmctl") }
sub pp_shmread { listop(@_, "shmread") }
sub pp_shmwrite { listop(@_, "shmwrite") }
sub pp_msgget { listop(@_, "msgget") }
sub pp_msgctl { listop(@_, "msgctl") }
sub pp_msgsnd { listop(@_, "msgsnd") }
sub pp_msgrcv { listop(@_, "msgrcv") }
sub pp_semget { listop(@_, "semget") }
sub pp_semctl { listop(@_, "semctl") }
sub pp_semop { listop(@_, "semop") }
sub pp_ghbyaddr { listop(@_, "gethostbyaddr") }
sub pp_gnbyaddr { listop(@_, "getnetbyaddr") }
sub pp_gpbynumber { listop(@_, "getprotobynumber") }
sub pp_gsbyname { listop(@_, "getservbyname") }
sub pp_gsbyport { listop(@_, "getservbyport") }
sub pp_syscall { listop(@_, "syscall") }

sub pp_glob {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first->sibling;  # skip pushmark
    my $keyword =
        $op->flags & OPf_SPECIAL ? 'glob' : $self->keyword('glob');
    my $text = $self->deparse($kid);
    return $cx >= 5 || $self->{'parens'}
        ? "$keyword($text)"
        : "$keyword $text";
}

# Truncate is special because OPf_SPECIAL makes a bareword first arg
# be a filehandle. This could probably be better fixed in the core
# by moving the GV lookup into ck_truc.

sub pp_truncate {
    my $self = shift;
    my($op, $cx) = @_;
    my(@exprs);
    my $parens = ($cx >= 5) || $self->{'parens'};
    my $kid = $op->first->sibling;
    my $fh;
    if ($op->flags & OPf_SPECIAL) {
        # $kid is an OP_CONST
        $fh = $self->const_sv($kid)->PV;
    } else {
        $fh = $self->deparse($kid, 6);
        $fh = "+$fh" if not $parens and substr($fh, 0, 1) eq "(";
    }
    my $len = $self->deparse($kid->sibling, 6);
    my $name = $self->keyword('truncate');
    if ($parens) {
        return "$name($fh, $len)";
    } else {
        return "$name $fh, $len";
    }
}

sub indirop {
    my $self = shift;
    my($op, $cx, $name) = @_;
    my($expr, @exprs);
    my $firstkid = my $kid = $op->first->sibling;
    my $indir = "";
    if ($op->flags & OPf_STACKED) {
        $indir = $kid;
        $indir = $indir->first; # skip rv2gv
        if (is_scope($indir)) {
            $indir = "{" . $self->deparse($indir, 0) . "}";
            $indir = "{;}" if $indir eq "{}";
        } elsif ($indir->name eq "const" && $indir->private & OPpCONST_BARE) {
            $indir = $self->const_sv($indir)->PV;
        } else {
            $indir = $self->deparse($indir, 24);
        }
        $indir = $indir . " ";
        $kid = $kid->sibling;
    }
    if ($name eq "sort" && $op->private & (OPpSORT_NUMERIC | OPpSORT_INTEGER)) {
        $indir = ($op->private & OPpSORT_DESCEND) ? '{$b <=> $a} '
                                                  : '{$a <=> $b} ';
    }
    elsif ($name eq "sort" && $op->private & OPpSORT_DESCEND) {
        $indir = '{$b cmp $a} ';
    }
    for (; !null($kid); $kid = $kid->sibling) {
        $expr = $self->deparse($kid, !$indir && $kid == $firstkid && $name eq "sort" && $firstkid->name eq "entersub" ? 16 : 6);
        push @exprs, $expr;
    }
    my $name2;
    if ($name eq "sort" && $op->private & OPpSORT_REVERSE) {
        $name2 = $self->keyword('reverse') . ' ' . $self->keyword('sort');
    }
    else { $name2 = $self->keyword($name) }
    if ($name eq "sort" && ($op->private & OPpSORT_INPLACE)) {
        return "$exprs[0] = $name2 $indir $exprs[0]";
    }

    my $args = $indir . join(", ", @exprs);
    if ($indir ne "" && $name eq "sort") {
        # We don't want to say "sort(f 1, 2, 3)", since perl -w will
        # give bareword warnings in that case. Therefore if context
        # requires, we'll put parens around the outside "(sort f 1, 2,
        # 3)". Unfortunately, we'll currently think the parens are
        # necessary more often that they really are, because we don't
        # distinguish which side of an assignment we're on.
        if ($cx >= 5) {
            return "($name2 $args)";
        } else {
            return "$name2 $args";
        }
    } elsif (
        !$indir && $name eq "sort"
      && !null($op->first->sibling)
      && $op->first->sibling->name eq 'entersub'
    ) {
        # We cannot say sort foo(bar), as foo will be interpreted as a
        # comparison routine.  We have to say sort(...) in that case.
        return "$name2($args)";
    } else {
        return length $args
                ? $self->maybe_parens_func($name2, $args, $cx, 5)
                : $name2 . '()' x (7 < $cx);
    }

}

sub pp_prtf { indirop(@_, "printf") }
sub pp_print { indirop(@_, "print") }
sub pp_say  { indirop(@_, "say") }
sub pp_sort { indirop(@_, "sort") }

sub mapop {
    my $self = shift;
    my($op, $cx, $name) = @_;
    my($expr, @exprs);
    my $kid = $op->first; # this is the (map|grep)start
    $kid = $kid->first->sibling; # skip a pushmark
    my $code = $kid->first; # skip a null
    if (is_scope $code) {
        $code = "{" . $self->deparse($code, 0) . "} ";
    } else {
        $code = $self->deparse($code, 24);
        $code .= ", " if !null($kid->sibling);
    }
    $kid = $kid->sibling;
    for (; !null($kid); $kid = $kid->sibling) {
        $expr = $self->deparse($kid, 6);
        push @exprs, $expr if defined $expr;
    }
    return $self->maybe_parens_func($self->keyword($name),
                                    $code . join(", ", @exprs), $cx, 5);
}

sub pp_mapwhile { mapop(@_, "map") }
sub pp_grepwhile { mapop(@_, "grep") }
sub pp_mapstart { baseop(@_, "map") }
sub pp_grepstart { baseop(@_, "grep") }

my %uses_intro;
BEGIN {
    @uses_intro{
        eval { require B::Op_private }
          ? @{$B::Op_private::ops_using{OPpLVAL_INTRO}}
          : qw(gvsv rv2sv rv2hv rv2gv rv2av aelem helem aslice
               hslice delete padsv padav padhv enteriter entersub padrange
               pushmark cond_expr refassign list)
    } = ();
    delete @uses_intro{qw( lvref lvrefslice lvavref entersub )};
}


# Look for a my/state attribute declaration in a list or ex-list.
# Returns undef if not found, 'my($x, @a) :Foo(bar)' etc otherwise.
#
# There are three basic tree structs that are expected:
#
# my $x :foo;
#      <1> ex-list vK/LVINTRO ->c
#         <0> ex-pushmark v ->3
#         <1> entersub[t2] vKRS*/TARG ->b
#                ....
#         <0> padsv[$x:64,65] vM/LVINTRO ->c
#
# my @a :foo;
# my %h :foo;
#
#      <1> ex-list vK ->c
#         <0> ex-pushmark v ->3
#         <0> padav[@a:64,65] vM/LVINTRO ->4
#         <1> entersub[t2] vKRS*/TARG ->c
#            ....
#
# my ($x,@a,%h) :foo;
#
#      <;> nextstate(main 64 -e:1) v:{ ->3
#      <@> list vKP ->w
#         <0> pushmark vM/LVINTRO ->4
#         <0> padsv[$x:64,65] vM/LVINTRO ->5
#         <0> padav[@a:64,65] vM/LVINTRO ->6
#         <0> padhv[%h:64,65] vM/LVINTRO ->7
#         <1> entersub[t4] vKRS*/TARG ->f
#            ....
#         <1> entersub[t5] vKRS*/TARG ->n
#            ....
#         <1> entersub[t6] vKRS*/TARG ->v
#           ....
# where the entersub in all cases looks like
#        <1> entersub[t2] vKRS*/TARG ->c
#           <0> pushmark s ->5
#           <$> const[PV "attributes"] sM ->6
#           <$> const[PV "main"] sM ->7
#           <1> srefgen sKM/1 ->9
#              <1> ex-list lKRM ->8
#                 <0> padsv[@a:64,65] sRM ->8
#           <$> const[PV "foo"] sM ->a
#           <.> method_named[PV "import"] ->b

sub maybe_var_attr {
    my ($self, $op, $cx) = @_;

    my $kid = $op->first->sibling; # skip pushmark
    return if class($kid) eq 'NULL';

    my $lop;
    my $type;

    # Extract out all the pad ops and entersub ops into
    # @padops and @entersubops. Return if anything else seen.
    # Also determine what class (if any) all the pad vars belong to
    my $class;
    my $decl; # 'my' or 'state'
    my (@padops, @entersubops);
    for ($lop = $kid; !null($lop); $lop = $lop->sibling) {
        my $lopname = $lop->name;
        my $loppriv = $lop->private;
        if ($lopname =~ /^pad[sah]v$/) {
            return unless $loppriv & OPpLVAL_INTRO;

            my $padname = $self->padname_sv($lop->targ);
            my $thisclass = ($padname->FLAGS & SVpad_TYPED)
                                ? $padname->SvSTASH->NAME : 'main';

            # all pad vars must be in the same class
            $class //= $thisclass;
            return unless $thisclass eq $class;

            # all pad vars must be the same sort of declaration
            # (all my, all state, etc)
            my $this = ($loppriv & OPpPAD_STATE) ? 'state' : 'my';
            if (defined $decl) {
                return unless $this eq $decl;
            }
            $decl = $this;

            push @padops, $lop;
        }
        elsif ($lopname eq 'entersub') {
            push @entersubops, $lop;
        }
        else {
            return;
        }
    }

    return unless @padops && @padops == @entersubops;

    # there should be a balance: each padop has a corresponding
    # 'attributes'->import() method call, in the same order.

    my @varnames;
    my $attr_text;

    for my $i (0..$#padops) {
        my $padop = $padops[$i];
        my $esop  = $entersubops[$i];

        push @varnames, $self->padname($padop->targ);

        return unless ($esop->flags & OPf_KIDS);

        my $kid = $esop->first;
        return unless $kid->type == OP_PUSHMARK;

        $kid = $kid->sibling;
        return unless $$kid && $kid->type == OP_CONST;
        return unless $self->const_sv($kid)->PV eq 'attributes';

        $kid = $kid->sibling;
        return unless $$kid && $kid->type == OP_CONST; # __PACKAGE__

        $kid = $kid->sibling;
        return unless  $$kid
                    && $kid->name eq "srefgen"
                    && ($kid->flags & OPf_KIDS)
                    && ($kid->first->flags & OPf_KIDS)
                    && $kid->first->first->name =~ /^pad[sah]v$/
                    && $kid->first->first->targ == $padop->targ;

        $kid = $kid->sibling;
        my @attr;
        while ($$kid) {
            last if ($kid->type != OP_CONST);
            push @attr, $self->const_sv($kid)->PV;
            $kid = $kid->sibling;
        }
        return unless @attr;
        my $thisattr = ":" . join(' ', @attr);
        $attr_text //= $thisattr;
        # all import calls must have the same list of attributes
        return unless $attr_text eq $thisattr;

        return unless $kid->name eq 'method_named';
        return unless $self->meth_sv($kid)->PV eq 'import';

        $kid = $kid->sibling;
        return if $$kid;
    }

    my $res = $decl;
    $res .= " $class " if $class ne 'main';
    $res .=
            (@varnames > 1)
            ? "(" . join(', ', @varnames) . ')'
            : " $varnames[0]";

    return "$res $attr_text";
}


sub pp_list {
    my $self = shift;
    my($op, $cx) = @_;

    {
        # might be my ($s,@a,%h) :Foo(bar);
        my $my_attr = maybe_var_attr($self, $op, $cx);
        return $my_attr if defined $my_attr;
    }

    my($expr, @exprs);
    my $kid = $op->first->sibling; # skip pushmark
    return '' if class($kid) eq 'NULL';
    my $lop;
    my $local = "either"; # could be local(...), my(...), state(...) or our(...)
    my $type;
    for ($lop = $kid; !null($lop); $lop = $lop->sibling) {
        my $lopname = $lop->name;
        my $loppriv = $lop->private;
        my $newtype;
        if ($lopname =~ /^pad[ash]v$/ && $loppriv & OPpLVAL_INTRO) {
            if ($loppriv & OPpPAD_STATE) { # state()
                ($local = "", last) if $local !~ /^(?:either|state)$/;
                $local = "state";
            } else { # my()
                ($local = "", last) if $local !~ /^(?:either|my)$/;
                $local = "my";
            }
            my $padname = $self->padname_sv($lop->targ);
            if ($padname->FLAGS & SVpad_TYPED) {
                $newtype = $padname->SvSTASH->NAME;
            }
        } elsif ($lopname =~ /^(?:gv|rv2)([ash])v$/
                        && $loppriv & OPpOUR_INTRO
                or $lopname eq "null" && class($lop) eq 'UNOP'
                        && $lop->first->name eq "gvsv"
                        && $lop->first->private & OPpOUR_INTRO) { # our()
            my $newlocal = "local " x !!($loppriv & OPpLVAL_INTRO) . "our";
            ($local = "", last)
                if $local ne 'either' && $local ne $newlocal;
            $local = $newlocal;
            my $funny = !$1 || $1 eq 's' ? '$' : $1 eq 'a' ? '@' : '%';
            if (my $t = $self->find_our_type(
                    $funny . $self->gv_or_padgv($lop->first)->NAME
               )) {
                $newtype = $t;
            }
        } elsif ($lopname ne 'undef'
           and    !($loppriv & OPpLVAL_INTRO)
               || !exists $uses_intro{$lopname eq 'null'
                                        ? substr B::ppname($lop->targ), 3
                                        : $lopname})
        {
            $local = ""; # or not
            last;
        } elsif ($lopname ne "undef")
        {
            # local()
            ($local = "", last) if $local !~ /^(?:either|local)$/;
            $local = "local";
        }
        if (defined $type && defined $newtype && $newtype ne $type) {
            $local = '';
            last;
        }
        $type = $newtype;
    }
    $local = "" if $local eq "either"; # no point if it's all undefs
    $local &&= join ' ', map $self->keyword($_), split / /, $local;
    $local .= " $type " if $local && length $type;
    return $self->deparse($kid, $cx) if null $kid->sibling and not $local;
    for (; !null($kid); $kid = $kid->sibling) {
        if ($local) {
            if (class($kid) eq "UNOP" and $kid->first->name eq "gvsv") {
                $lop = $kid->first;
            } else {
                $lop = $kid;
            }
            $self->{'avoid_local'}{$$lop}++;
            $expr = $self->deparse($kid, 6);
            delete $self->{'avoid_local'}{$$lop};
        } else {
            $expr = $self->deparse($kid, 6);
        }
        push @exprs, $expr;
    }
    if ($local) {
        if (@exprs == 1 && ($local eq 'state' || $local eq 'CORE::state')) {
            # 'state @a = ...' is legal, while 'state(@a) = ...' currently isn't
            return "$local $exprs[0]";
        }
        return "$local(" . join(", ", @exprs) . ")";
    } else {
        return $self->maybe_parens( join(", ", @exprs), $cx, 6);        
    }
}

sub is_ifelse_cont {
    my $op = shift;
    return ($op->name eq "null" and class($op) eq "UNOP"
            and $op->first->name =~ /^(and|cond_expr)$/
            and is_scope($op->first->first->sibling));
}

sub pp_cond_expr {
    my $self = shift;
    my($op, $cx) = @_;
    my $cond = $op->first;
    my $true = $cond->sibling;
    my $false = $true->sibling;
    my $cuddle = $self->{'cuddle'};
    unless ($cx < 1 and (is_scope($true) and $true->name ne "null") and
            (is_scope($false) || is_ifelse_cont($false))
            and $self->{'expand'} < 7) {
        $cond = $self->deparse($cond, 8);
        $true = $self->deparse($true, 6);
        $false = $self->deparse($false, 8);
        return $self->maybe_parens("$cond ? $true : $false", $cx, 8);
    }

    $cond = $self->deparse($cond, 1);
    $true = $self->deparse($true, 0);
    my $head = $self->keyword("if") . " ($cond) {\n\t$true\n\b}";
    my @elsifs;
    my $elsif;
    while (!null($false) and is_ifelse_cont($false)) {
        my $newop = $false->first;
        my $newcond = $newop->first;
        my $newtrue = $newcond->sibling;
        $false = $newtrue->sibling; # last in chain is OP_AND => no else
        if ($newcond->name eq "lineseq")
        {
            # lineseq to ensure correct line numbers in elsif()
            # Bug #37302 fixed by change #33710.
            $newcond = $newcond->first->sibling;
        }
        $newcond = $self->deparse($newcond, 1);
        $newtrue = $self->deparse($newtrue, 0);
        $elsif ||= $self->keyword("elsif");
        push @elsifs, "$elsif ($newcond) {\n\t$newtrue\n\b}";
    }
    if (!null($false)) {
        $false = $cuddle . $self->keyword("else") . " {\n\t" .
          $self->deparse($false, 0) . "\n\b}\cK";
    } else {
        $false = "\cK";
    }
    return $head . join($cuddle, "", @elsifs) . $false;
}

sub pp_once {
    my ($self, $op, $cx) = @_;
    my $cond = $op->first;
    my $true = $cond->sibling;

    my $ret = $self->deparse($true, $cx);
    $ret =~ s/^(\(?)\$/$1 . $self->keyword("state") . ' $'/e;
    $ret;
}

sub loop_common {
    my $self = shift;
    my($op, $cx, $init) = @_;
    my $enter = $op->first;
    my $kid = $enter->sibling;
    local(@$self{qw'curstash warnings hints hinthash'})
                = @$self{qw'curstash warnings hints hinthash'};
    my $head = "";
    my $bare = 0;
    my $body;
    my $cond = undef;
    my $name;
    if ($kid->name eq "lineseq") { # bare or infinite loop
        if ($kid->last->name eq "unstack") { # infinite
            $head = "while (1) "; # Can't use for(;;) if there's a continue
            $cond = "";
        } else {
            $bare = 1;
        }
        $body = $kid;
    } elsif ($enter->name eq "enteriter") { # foreach
        my $ary = $enter->first->sibling; # first was pushmark
        my $var = $ary->sibling;
        if ($ary->name eq 'null' and $enter->private & OPpITER_REVERSED) {
            # "reverse" was optimised away
            $ary = listop($self, $ary->first->sibling, 1, 'reverse');
        } elsif ($enter->flags & OPf_STACKED
            and not null $ary->first->sibling->sibling)
        {
            $ary = $self->deparse($ary->first->sibling, 9) . " .. " .
              $self->deparse($ary->first->sibling->sibling, 9);
        } else {
            $ary = $self->deparse($ary, 1);
        }
        if (null $var) {
            $var = $self->pp_padsv($enter, 1, 1);
        } elsif ($var->name eq "rv2gv") {
            $var = $self->pp_rv2sv($var, 1);
            if ($enter->private & OPpOUR_INTRO) {
                # our declarations don't have package names
                $var =~ s/^(.).*::/$1/;
                $var = "our $var";
            }
        } elsif ($var->name eq "gv") {
            $var = "\$" . $self->deparse($var, 1);
        } else {
            $var = $self->deparse($var, 1);
        }
        $body = $kid->first->first->sibling; # skip OP_AND and OP_ITER
        if (!is_state $body->first and $body->first->name !~ /^(?:stub|leave|scope)$/) {
            confess unless $var eq '$_';
            $body = $body->first;
            return $self->deparse($body, 2) . " "
                 . $self->keyword("foreach") . " ($ary)";
        }
        $head = "foreach $var ($ary) ";
    } elsif ($kid->name eq "null") { # while/until
        $kid = $kid->first;
        $name = {"and" => "while", "or" => "until"}->{$kid->name};
        $cond = $kid->first;
        $body = $kid->first->sibling;
    } elsif ($kid->name eq "stub") { # bare and empty
        return "{;}"; # {} could be a hashref
    }
    # If there isn't a continue block, then the next pointer for the loop
    # will point to the unstack, which is kid's last child, except
    # in a bare loop, when it will point to the leaveloop. When neither of
    # these conditions hold, then the second-to-last child is the continue
    # block (or the last in a bare loop).
    my $cont_start = $enter->nextop;
    my $cont;
    my $precond;
    my $postcond;
    if ($$cont_start != $$op && ${$cont_start} != ${$body->last}) {
        if ($bare) {
            $cont = $body->last;
        } else {
            $cont = $body->first;
            while (!null($cont->sibling->sibling)) {
                $cont = $cont->sibling;
            }
        }
        my $state = $body->first;
        my $cuddle = $self->{'cuddle'};
        my @states;
        for (; $$state != $$cont; $state = $state->sibling) {
            push @states, $state;
        }
        $body = $self->lineseq(undef, 0, @states);
        if (defined $cond and not is_scope $cont and $self->{'expand'} < 3) {
            $precond = "for ($init; ";
            $postcond = "; " . $self->deparse($cont, 1) .") ";
            $cont = "\cK";
        } else {
            $cont = $cuddle . "continue {\n\t" .
              $self->deparse($cont, 0) . "\n\b}\cK";
        }
    } else {
        return "" if !defined $body;
        if (length $init) {
            $precond = "for ($init; ";
            $postcond = ";) ";
        }
        $cont = "\cK";
        $body = $self->deparse($body, 0);
    }
    if ($precond) { # for(;;)
        $cond &&= $name eq 'until'
                    ? listop($self, undef, 1, "not", $cond->first)
                    : $self->deparse($cond, 1);
        $head = "$precond$cond$postcond";
    }
    if ($name && !$head) {
        ref $cond and $cond = $self->deparse($cond, 1);
        $head = "$name ($cond) ";
    }
    $head =~ s/^(for(?:each)?|while|until)/$self->keyword($1)/e;
    $body =~ s/;?$/;\n/;

    return $head . "{\n\t" . $body . "\b}" . $cont;
}

sub pp_leaveloop { shift->loop_common(@_, "") }

sub for_loop {
    my $self = shift;
    my($op, $cx) = @_;
    my $init = $self->deparse($op, 1);
    my $s = $op->sibling;
    my $ll = $s->name eq "unstack" ? $s->sibling : $s->first->sibling;
    return $self->loop_common($ll, $cx, $init);
}

sub pp_leavetry {
    my $self = shift;
    return "eval {\n\t" . $self->pp_leave(@_) . "\n\b}";
}

sub _op_is_or_was {
  my ($op, $expect_type) = @_;
  my $type = $op->type;
  return($type == $expect_type
         || ($type == OP_NULL && $op->targ == $expect_type));
}

sub pp_null {
    my($self, $op, $cx) = @_;

    # might be 'my $s :Foo(bar);'
    if ($op->targ == OP_LIST) {
        my $my_attr = maybe_var_attr($self, $op, $cx);
        return $my_attr if defined $my_attr;
    }

    if (class($op) eq "OP") {
        # old value is lost
        return $self->{'ex_const'} if $op->targ == OP_CONST;
    } elsif (class ($op) eq "COP") {
            return &pp_nextstate;
    } elsif ($op->first->name eq 'pushmark'
             or $op->first->name eq 'null'
                && $op->first->targ == OP_PUSHMARK
                && _op_is_or_was($op, OP_LIST)) {
        return $self->pp_list($op, $cx);
    } elsif ($op->first->name eq "enter") {
        return $self->pp_leave($op, $cx);
    } elsif ($op->first->name eq "leave") {
        return $self->pp_leave($op->first, $cx);
    } elsif ($op->first->name eq "scope") {
        return $self->pp_scope($op->first, $cx);
    } elsif ($op->targ == OP_STRINGIFY) {
        return $self->dquote($op, $cx);
    } elsif ($op->targ == OP_GLOB) {
        return $self->pp_glob(
                 $op->first    # entersub
                    ->first    # ex-list
                    ->first    # pushmark
                    ->sibling, # glob
                 $cx
               );
    } elsif (!null($op->first->sibling) and
             $op->first->sibling->name eq "readline" and
             $op->first->sibling->flags & OPf_STACKED) {
        return $self->maybe_parens($self->deparse($op->first, 7) . " = "
                                   . $self->deparse($op->first->sibling, 7),
                                   $cx, 7);
    } elsif (!null($op->first->sibling) and
             $op->first->sibling->name =~ /^transr?\z/ and
             $op->first->sibling->flags & OPf_STACKED) {
        return $self->maybe_parens($self->deparse($op->first, 20) . " =~ "
                                   . $self->deparse($op->first->sibling, 20),
                                   $cx, 20);
    } elsif ($op->flags & OPf_SPECIAL && $cx < 1 && !$op->targ) {
        return ($self->lex_in_scope("&do") ? "CORE::do" : "do")
             . " {\n\t". $self->deparse($op->first, $cx) ."\n\b};";
    } elsif (!null($op->first->sibling) and
             $op->first->sibling->name eq "null" and
             class($op->first->sibling) eq "UNOP" and
             $op->first->sibling->first->flags & OPf_STACKED and
             $op->first->sibling->first->name eq "rcatline") {
        return $self->maybe_parens($self->deparse($op->first, 18) . " .= "
                                   . $self->deparse($op->first->sibling, 18),
                                   $cx, 18);
    } else {
        return $self->deparse($op->first, $cx);
    }
}

sub padname {
    my $self = shift;
    my $targ = shift;
    return $self->padname_sv($targ)->PVX;
}

sub padany {
    my $self = shift;
    my $op = shift;
    return substr($self->padname($op->targ), 1); # skip $/@/%
}

sub pp_padsv {
    my $self = shift;
    my($op, $cx, $forbid_parens) = @_;
    my $targ = $op->targ;
    return $self->maybe_my($op, $cx, $self->padname($targ),
                           $self->padname_sv($targ),
                           $forbid_parens);
}

sub pp_padav { pp_padsv(@_) }

# prepend 'keys' where its been optimised away, with suitable handling
# of CORE:: and parens

sub add_keys_keyword {
    my ($self, $str, $cx) = @_;
    $str = $self->maybe_parens($str, $cx, 16);
    # 'keys %h' versus 'keys(%h)'
    $str = " $str" unless $str =~ /^\(/;
    return $self->keyword("keys") . $str;
}

sub pp_padhv {
    my ($self, $op, $cx) = @_;
    my $str =  pp_padsv(@_);
    # with OPpPADHV_ISKEYS the keys op is optimised away, except
    # in scalar context the old op is kept (but not executed) so its targ
    # can be used.
    if (     ($op->private & OPpPADHV_ISKEYS)
        && !(($op->flags & OPf_WANT) == OPf_WANT_SCALAR))
    {
        $str = $self->add_keys_keyword($str, $cx);
    }
    $str;
}

sub gv_or_padgv {
    my $self = shift;
    my $op = shift;
    if (class($op) eq "PADOP") {
        return $self->padval($op->padix);
    } else { # class($op) eq "SVOP"
        return $op->gv;
    }
}

sub pp_gvsv {
    my $self = shift;
    my($op, $cx) = @_;
    my $gv = $self->gv_or_padgv($op);
    return $self->maybe_local($op, $cx, $self->stash_variable("\$",
                                 $self->gv_name($gv), $cx));
}

sub pp_gv {
    my $self = shift;
    my($op, $cx) = @_;
    my $gv = $self->gv_or_padgv($op);
    return $self->maybe_qualify("", $self->gv_name($gv));
}

sub pp_aelemfast_lex {
    my $self = shift;
    my($op, $cx) = @_;
    my $name = $self->padname($op->targ);
    $name =~ s/^@/\$/;
    my $i = $op->private;
    $i -= 256 if $i > 127;
    return $name . "[" .  ($i + $self->{'arybase'}) . "]";
}

sub pp_aelemfast {
    my $self = shift;
    my($op, $cx) = @_;
    # optimised PADAV, pre 5.15
    return $self->pp_aelemfast_lex(@_) if ($op->flags & OPf_SPECIAL);

    my $gv = $self->gv_or_padgv($op);
    my($name,$quoted) = $self->stash_variable_name('@',$gv);
    $name = $quoted ? "$name->" : '$' . $name;
    my $i = $op->private;
    $i -= 256 if $i > 127;
    return $name . "[" .  ($i + $self->{'arybase'}) . "]";
}

sub rv2x {
    my $self = shift;
    my($op, $cx, $type) = @_;

    if (class($op) eq 'NULL' || !$op->can("first")) {
        carp("Unexpected op in pp_rv2x");
        return 'XXX';
    }
    my $kid = $op->first;
    if ($kid->name eq "gv") {
        return $self->stash_variable($type,
                    $self->gv_name($self->gv_or_padgv($kid)), $cx);
    } elsif (is_scalar $kid) {
        my $str = $self->deparse($kid, 0);
        if ($str =~ /^\$([^\w\d])\z/) {
            # "$$+" isn't a legal way to write the scalar dereference
            # of $+, since the lexer can't tell you aren't trying to
            # do something like "$$ + 1" to get one more than your
            # PID. Either "${$+}" or "$${+}" are workable
            # disambiguations, but if the programmer did the former,
            # they'd be in the "else" clause below rather than here.
            # It's not clear if this should somehow be unified with
            # the code in dq and re_dq that also adds lexer
            # disambiguation braces.
            $str = '$' . "{$1}"; #'
        }
        return $type . $str;
    } else {
        return $type . "{" . $self->deparse($kid, 0) . "}";
    }
}

sub pp_rv2sv { maybe_local(@_, rv2x(@_, "\$")) }
sub pp_rv2gv { maybe_local(@_, rv2x(@_, "*")) }

sub pp_rv2hv {
    my ($self, $op, $cx) = @_;
    my $str = rv2x(@_, "%");
    if ($op->private & OPpRV2HV_ISKEYS) {
        $str = $self->add_keys_keyword($str, $cx);
    }
    return maybe_local(@_, $str);
}

# skip rv2av
sub pp_av2arylen {
    my $self = shift;
    my($op, $cx) = @_;
    if ($op->first->name eq "padav") {
        return $self->maybe_local($op, $cx, '$#' . $self->padany($op->first));
    } else {
        return $self->maybe_local($op, $cx,
                                  $self->rv2x($op->first, $cx, '$#'));
    }
}

# skip down to the old, ex-rv2cv
sub pp_rv2cv {
    my ($self, $op, $cx) = @_;
    if (!null($op->first) && $op->first->name eq 'null' &&
        $op->first->targ == OP_LIST)
    {
        return $self->rv2x($op->first->first->sibling, $cx, "&")
    }
    else {
        return $self->rv2x($op, $cx, "")
    }
}

sub list_const {
    my $self = shift;
    my($cx, @list) = @_;
    my @a = map $self->const($_, 6), @list;
    if (@a == 0) {
        return "()";
    } elsif (@a == 1) {
        return $a[0];
    } elsif ( @a > 2 and !grep(!/^-?\d+$/, @a)) {
        # collapse (-1,0,1,2) into (-1..2)
        my ($s, $e) = @a[0,-1];
        my $i = $s;
        return $self->maybe_parens("$s..$e", $cx, 9)
          unless grep $i++ != $_, @a;
    }
    return $self->maybe_parens(join(", ", @a), $cx, 6);
}

sub pp_rv2av {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first;
    if ($kid->name eq "const") { # constant list
        my $av = $self->const_sv($kid);
        return $self->list_const($cx, $av->ARRAY);
    } else {
        return $self->maybe_local($op, $cx, $self->rv2x($op, $cx, "\@"));
    }
 }

sub is_subscriptable {
    my $op = shift;
    if ($op->name =~ /^([ahg]elem|multideref$)/) {
        return 1;
    } elsif ($op->name eq "entersub") {
        my $kid = $op->first;
        return 0 unless null $kid->sibling;
        $kid = $kid->first;
        $kid = $kid->sibling until null $kid->sibling;
        return 0 if is_scope($kid);
        $kid = $kid->first;
        return 0 if $kid->name eq "gv" || $kid->name eq "padcv";
        return 0 if is_scalar($kid);
        return is_subscriptable($kid);  
    } else {
        return 0;
    }
}

sub elem_or_slice_array_name
{
    my $self = shift;
    my ($array, $left, $padname, $allow_arrow) = @_;

    if ($array->name eq $padname) {
        return $self->padany($array);
    } elsif (is_scope($array)) { # ${expr}[0]
        return "{" . $self->deparse($array, 0) . "}";
    } elsif ($array->name eq "gv") {
        ($array, my $quoted) =
            $self->stash_variable_name(
                $left eq '[' ? '@' : '%', $self->gv_or_padgv($array)
            );
        if (!$allow_arrow && $quoted) {
            # This cannot happen.
            die "Invalid variable name $array for slice";
        }
        return $quoted ? "$array->" : $array;
    } elsif (!$allow_arrow || is_scalar $array) { # $x[0], $$x[0], ...
        return $self->deparse($array, 24);
    } else {
        return undef;
    }
}

sub elem_or_slice_single_index
{
    my $self = shift;
    my ($idx) = @_;

    $idx = $self->deparse($idx, 1);

    # Outer parens in an array index will confuse perl
    # if we're interpolating in a regular expression, i.e.
    # /$x$foo[(-1)]/ is *not* the same as /$x$foo[-1]/
    #
    # If $self->{parens}, then an initial '(' will
    # definitely be paired with a final ')'. If
    # !$self->{parens}, the misleading parens won't
    # have been added in the first place.
    #
    # [You might think that we could get "(...)...(...)"
    # where the initial and final parens do not match
    # each other. But we can't, because the above would
    # only happen if there's an infix binop between the
    # two pairs of parens, and *that* means that the whole
    # expression would be parenthesized as well.]
    #
    $idx =~ s/^\((.*)\)$/$1/ if $self->{'parens'};

    # Hash-element braces will autoquote a bareword inside themselves.
    # We need to make sure that C<$hash{warn()}> doesn't come out as
    # C<$hash{warn}>, which has a quite different meaning. Currently
    # B::Deparse will always quote strings, even if the string was a
    # bareword in the original (i.e. the OPpCONST_BARE flag is ignored
    # for constant strings.) So we can cheat slightly here - if we see
    # a bareword, we know that it is supposed to be a function call.
    #
    $idx =~ s/^([A-Za-z_]\w*)$/$1()/;

    return $idx;
}

sub elem {
    my $self = shift;
    my ($op, $cx, $left, $right, $padname) = @_;
    my($array, $idx) = ($op->first, $op->first->sibling);

    $idx = $self->elem_or_slice_single_index($idx);

    unless ($array->name eq $padname) { # Maybe this has been fixed     
        $array = $array->first; # skip rv2av (or ex-rv2av in _53+)
    }
    if (my $array_name=$self->elem_or_slice_array_name
            ($array, $left, $padname, 1)) {
        return ($array_name =~ /->\z/
                    ? $array_name
                    : $array_name eq '#' ? '${#}' : "\$" . $array_name)
              . $left . $idx . $right;
    } else {
        # $x[20][3]{hi} or expr->[20]
        my $arrow = is_subscriptable($array) ? "" : "->";
        return $self->deparse($array, 24) . $arrow . $left . $idx . $right;
    }

}

# a simplified version of elem_or_slice_array_name()
# for the use of pp_multideref

sub multideref_var_name {
    my $self = shift;
    my ($gv, $is_hash) = @_;

    my ($name, $quoted) =
        $self->stash_variable_name( $is_hash  ? '%' : '@', $gv);
    return $quoted ? "$name->"
                   : $name eq '#'
                        ? '${#}'       # avoid ${#}[1] => $#[1]
                        : '$' . $name;
}


# deparse an OP_MULTICONCAT. If $in_dq is 1, we're within
# a double-quoted string, so for example.
#     "abc\Qdef$x\Ebar"
# might get compiled as
#    multiconcat("abc", metaquote(multiconcat("def", $x)), "bar")
# and the inner multiconcat should be deparsed as C<def$x> rather than
# the normal C<def . $x>
# Ditto if  $in_dq is 2, handle qr/...\Qdef$x\E.../.

sub do_multiconcat {
    my $self = shift;
    my($op, $cx, $in_dq) = @_;

    my $kid;
    my @kids;
    my $assign;
    my $append;
    my $lhs = "";

    for ($kid = $op->first; !null $kid; $kid = $kid->sibling) {
        # skip the consts and/or padsv we've optimised away
        push @kids, $kid
            unless $kid->type == OP_NULL
              && (   $kid->targ == OP_PADSV
                  || $kid->targ == OP_CONST
                  || $kid->targ == OP_PUSHMARK);
    }

    $append = ($op->private & OPpMULTICONCAT_APPEND);

    if ($op->private & OPpTARGET_MY) {
        # '$lex  = ...' or '$lex .= ....' or 'my $lex = '
        $lhs = $self->padname($op->targ);
        $lhs = "my $lhs" if ($op->private & OPpLVAL_INTRO);
        $assign = 1;
    }
    elsif ($op->flags & OPf_STACKED) {
        # 'expr  = ...' or 'expr .= ....'
        my $expr = $append ? shift(@kids) : pop(@kids);
        $lhs = $self->deparse($expr, 7);
        $assign = 1;
    }

    if ($assign) {
        $lhs .=  $append ? ' .= ' : ' = ';
    }

    my ($nargs, $const_str, @const_lens) = $op->aux_list($self->{curcv});

    my @consts;
    my $i = 0;
    for (@const_lens) {
        if ($_ == -1) {
            push @consts, undef;
        }
        else {
            push @consts, substr($const_str, $i, $_);
        my @args;
            $i += $_;
        }
    }

    my $rhs = "";

    if (   $in_dq
        || (($op->private & OPpMULTICONCAT_STRINGIFY) && !$self->{'unquote'}))
    {
        # "foo=$foo bar=$bar "
        my $not_first;
        while (@consts) {
            if ($not_first) {
                my $s = $self->dq(shift(@kids), 18);
                # don't deparse "a${$}b" as "a$$b"
                $s = '${$}' if $s eq '$$';
                $rhs = dq_disambiguate($rhs, $s);
            }
            $not_first = 1;
            my $c = shift @consts;
            if (defined $c) {
                if ($in_dq == 2) {
                    # in pattern: don't convert newline to '\n' etc etc
                    my $s = re_uninterp(escape_re(re_unback($c)));
                    $rhs = re_dq_disambiguate($rhs, $s)
                }
                else {
                    my $s = uninterp(escape_str(unback($c)));
                    $rhs = dq_disambiguate($rhs, $s)
                }
            }
        }
        return $rhs if $in_dq;
        $rhs = single_delim("qq", '"', $rhs, $self);
    }
    elsif ($op->private & OPpMULTICONCAT_FAKE) {
        # sprintf("foo=%s bar=%s ", $foo, $bar)

        my @all;
        @consts = map { $_ //= ''; s/%/%%/g; $_ } @consts;
        my $fmt = join '%s', @consts;
        push @all, $self->quoted_const_str($fmt);

        # the following is a stripped down copy of sub listop {}
        my $parens = $assign || ($cx >= 5) || $self->{'parens'};
        my $fullname = $self->keyword('sprintf');
        push @all, map $self->deparse($_, 6), @kids;

        $rhs = $parens
                ? "$fullname(" . join(", ", @all) . ")"
                : "$fullname " . join(", ", @all);
    }
    else {
        # "foo=" . $foo . " bar=" . $bar
        my @all;
        my $not_first;
        while (@consts) {
            push @all, $self->deparse(shift(@kids), 18) if $not_first;
            $not_first = 1;
            my $c = shift @consts;
            if (defined $c) {
                push @all, $self->quoted_const_str($c);