Remove version checks from B::Deparse’s imports

[perl5.git] / dist / B-Deparse / 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
         OPpLVAL_INTRO OPpOUR_INTRO OPpENTERSUB_AMPER OPpSLICE OPpCONST_BARE
         OPpTRANS_SQUASH OPpTRANS_DELETE OPpTRANS_COMPLEMENT OPpTARGET_MY
         OPpEXISTS_SUB OPpSORT_NUMERIC OPpSORT_INTEGER
         OPpSORT_REVERSE
         SVf_IOK SVf_NOK SVf_ROK SVf_POK SVpad_OUR SVf_FAKE SVs_RMG SVs_SMG
         CVf_METHOD CVf_LVALUE
         PMf_KEEP PMf_GLOBAL PMf_CONTINUE PMf_EVAL PMf_ONCE
         PMf_MULTILINE PMf_SINGLELINE PMf_FOLD PMf_EXTENDED);
$VERSION = "1.10";
use strict;
use vars qw/$AUTOLOAD/;
use warnings ();

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
                CVf_LOCKED OPpREVERSE_INPLACE
                PMf_NONDESTRUCT OPpCONST_ARYBASE OPpEVAL_BYTES)) {
        eval { import B $_ };
        no strict 'refs';
        *{$_} = sub () {0} unless *{$_}{CODE};
    }
}

# Changes between 0.50 and 0.51:
# - fixed nulled leave with live enter in sort { }
# - fixed reference constants (\"str")
# - handle empty programs gracefully
# - handle infinite loops (for (;;) {}, while (1) {})
# - differentiate between `for my $x ...' and `my $x; for $x ...'
# - various minor cleanups
# - moved globals into an object
# - added `-u', like B::C
# - package declarations using cop_stash
# - subs, formats and code sorted by cop_seq
# Changes between 0.51 and 0.52:
# - added pp_threadsv (special variables under USE_5005THREADS)
# - added documentation
# Changes between 0.52 and 0.53:
# - many changes adding precedence contexts and associativity
# - added `-p' and `-s' output style options
# - various other minor fixes
# Changes between 0.53 and 0.54:
# - added support for new `for (1..100)' optimization,
#   thanks to Gisle Aas
# Changes between 0.54 and 0.55:
# - added support for new qr// construct
# - added support for new pp_regcreset OP
# Changes between 0.55 and 0.56:
# - tested on base/*.t, cmd/*.t, comp/*.t, io/*.t
# - fixed $# on non-lexicals broken in last big rewrite
# - added temporary fix for change in opcode of OP_STRINGIFY
# - fixed problem in 0.54's for() patch in `for (@ary)'
# - fixed precedence in conditional of ?:
# - tweaked list paren elimination in `my($x) = @_'
# - made continue-block detection trickier wrt. null ops
# - fixed various prototype problems in pp_entersub
# - added support for sub prototypes that never get GVs
# - added unquoting for special filehandle first arg in truncate
# - print doubled rv2gv (a bug) as `*{*GV}' instead of illegal `**GV'
# - added semicolons at the ends of blocks
# - added -l `#line' declaration option -- fixes cmd/subval.t 27,28
# Changes between 0.56 and 0.561:
# - fixed multiply-declared my var in pp_truncate (thanks to Sarathy)
# - used new B.pm symbolic constants (done by Nick Ing-Simmons)
# Changes between 0.561 and 0.57:
# - stylistic changes to symbolic constant stuff
# - handled scope in s///e replacement code
# - added unquote option for expanding "" into concats, etc.
# - split method and proto parts of pp_entersub into separate functions
# - various minor cleanups
# Changes after 0.57:
# - added parens in \&foo (patch by Albert Dvornik)
# Changes between 0.57 and 0.58:
# - fixed `0' statements that weren't being printed
# - added methods for use from other programs
#   (based on patches from James Duncan and Hugo van der Sanden)
# - added -si and -sT to control indenting (also based on a patch from Hugo)
# - added -sv to print something else instead of '???'
# - preliminary version of utf8 tr/// handling
# Changes after 0.58:
# - uses of $op->ppaddr changed to new $op->name (done by Sarathy)
# - added support for Hugo's new OP_SETSTATE (like nextstate)
# Changes between 0.58 and 0.59
# - added support for Chip's OP_METHOD_NAMED
# - added support for Ilya's OPpTARGET_MY optimization
# - elided arrows before `()' subscripts when possible
# Changes between 0.59 and 0.60
# - support for method attributes was added
# - some warnings fixed
# - separate recognition of constant subs
# - rewrote continue block handling, now recognizing for loops
# - added more control of expanding control structures
# Changes between 0.60 and 0.61 (mostly by Robin Houston)
# - many bug-fixes
# - support for pragmas and 'use'
# - support for the little-used $[ variable
# - support for __DATA__ sections
# - UTF8 support
# - BEGIN, CHECK, INIT and END blocks
# - scoping of subroutine declarations fixed
# - compile-time output from the input program can be suppressed, so that the
#   output is just the deparsed code. (a change to O.pm in fact)
# - our() declarations
# - *all* the known bugs are now listed in the BUGS section
# - comprehensive test mechanism (TEST -deparse)
# Changes between 0.62 and 0.63 (mostly by Rafael Garcia-Suarez)
# - bug-fixes
# - new switch -P
# - support for command-line switches (-l, -0, etc.)
# Changes between 0.63 and 0.64
# - support for //, CHECK blocks, and assertions
# - improved handling of foreach loops and lexicals
# - option to use Data::Dumper for constants
# - more bug fixes
# - discovered lots more bugs not yet fixed
#
# ...
#
# Changes between 0.72 and 0.73
# - support new switch constructs

# 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 (were globals):
#
# 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,
# each value is an array of pairs, indicating the cop_seq of scopes
# in which a var of that name is valid.
#
# curcop:
# COP for statement being deparsed
#
# curstash:
# name of the current package for deparsed code
#
# subs_todo:
# array of [cop_seq, CV, is_format?] for subs and formats we still
# want to deparse
#
# 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.
#
# subs_deparsed
# Keeps track of fully qualified names of all deparsed subs.
#
# 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

# 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

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

sub todo {
    my $self = shift;
    my($cv, $is_form) = @_;
    return unless ($cv->FILE eq $0 || exists $self->{files}{$cv->FILE});
    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 {
        $seq = 0;
    }
    push @{$self->{'subs_todo'}}, [$seq, $cv, $is_form];
    unless ($is_form || class($cv->STASH) eq 'SPECIAL') {
        $self->{'subs_deparsed'}{$cv->STASH->NAME."::".$cv->GV->NAME} = 1;
    }
}

sub next_todo {
    my $self = shift;
    my $ent = shift @{$self->{'subs_todo'}};
    my $cv = $ent->[1];
    my $gv = $cv->GV;
    my $name = $self->gv_name($gv);
    if ($ent->[2]) {
        return "format $name =\n"
            . $self->deparse_format($ent->[1]). "\n";
    } else {
        $self->{'subs_declared'}{$name} = 1;
        if ($name eq "BEGIN") {
            my $use_dec = $self->begin_is_use($cv);
            if (defined ($use_dec) and $self->{'expand'} < 5) {
                return () if 0 == length($use_dec);
                return $use_dec;
            }
        }
        my $l = '';
        if ($self->{'linenums'}) {
            my $line = $gv->LINE;
            my $file = $gv->FILE;
            $l = "\n\f#line $line \"$file\"\n";
        }
        my $p = '';
        if (class($cv->STASH) ne "SPECIAL") {
            my $stash = $cv->STASH->NAME;
            if ($stash ne $self->{'curstash'}) {
                $p = "package $stash;\n";
                $name = "$self->{'curstash'}::$name" unless $name =~ /::/;
                $self->{'curstash'} = $stash;
            }
            $name =~ s/^\Q$stash\E::(?!\z|.*::)//;
        }
        return "${p}${l}sub $name " . $self->deparse_sub($cv);
    }
}

# 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'} = ($cv);
#require B::Debug;
#B::walkoptree($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";

    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 $self->const_sv($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; $svop->name ne "method_named";
                $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 = $self->const_sv($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) = @_;
    my (@ret, $stash);
    if (!defined $pack) {
        $pack = '';
        $stash = \%::;
    }
    else {
        $pack =~ s/(::)?$/::/;
        no strict 'refs';
        $stash = \%{"main::$pack"};
    }
    my %stash = svref_2object($stash)->ARRAY;
    while (my ($key, $val) = each %stash) {
        my $class = class($val);
        if ($class eq "PV") {
            # 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, $val->PV];
        } elsif ($class eq "IV" && !($val->FLAGS & SVf_ROK)) {
            # Just a name. As above.
            # But skip proxy constant subroutines, as some form of perl-space
            # visible code must have created them, be it a use statement, or
            # some direct symbol-table manipulation code that we will Deparse
            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 . $key, undef];
        } elsif ($class eq "GV") {
            if (class(my $cv = $val->CV) ne "SPECIAL") {
                next if $self->{'subs_done'}{$$val}++;
                next if $$val != ${$cv->GV};   # Ignore imposters
                $self->todo($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)
                    unless $pack eq '' && $key eq 'main::';
                    # avoid infinite recursion
            }
        }
    }
}

sub print_protos {
    my $self = shift;
    my $ar;
    my @ret;
    foreach $ar (@{$self->{'protos_todo'}}) {
        my $proto = (defined $ar->[1] ? " (". $ar->[1] . ")" : "");
        push @ret, "sub " . $ar->[0] .  "$proto;\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->{'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->{'hints'} &= 0xFF if $] < 5.009;
    $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 : ();
        for my $block (@BEGINs, @UNITCHECKs, @CHECKs, @INITs, @ENDs) {
            $self->todo($block, 0);
        }
        $self->stash_subs();
        local($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'}};
        print $self->indent($self->deparse_root(main_root)), "\n"
          unless null main_root;
        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 "package $laststash;\n"
                unless $laststash eq $self->{'curstash'};
            print "__DATA__\n";
            print readline(*{$laststash."::DATA"});
        }
    }
}

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

    $self->init();
    return $self->indent($self->deparse_sub(svref_2object($sub)));
}

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(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(@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;
    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 (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 deparse_sub {
    my $self = shift;
    my $cv = shift;
    my $proto = "";
Carp::confess("NULL in deparse_sub") if !defined($cv) || $cv->isa("B::NULL");
Carp::confess("SPECIAL in deparse_sub") if $cv->isa("B::SPECIAL");
    local $self->{'curcop'} = $self->{'curcop'};
    if ($cv->FLAGS & SVf_POK) {
        $proto = "(". $cv->PV . ") ";
    }
    if ($cv->CvFLAGS & (CVf_METHOD|CVf_LOCKED|CVf_LVALUE)) {
        $proto .= ": ";
        $proto .= "lvalue " if $cv->CvFLAGS & CVf_LVALUE;
        $proto .= "locked " if $cv->CvFLAGS & CVf_LOCKED;
        $proto .= "method " if $cv->CvFLAGS & CVf_METHOD;
    }

    local($self->{'curcv'}) = $cv;
    local($self->{'curcvlex'});
    local(@$self{qw'curstash warnings hints hinthash'})
                = @$self{qw'curstash warnings hints hinthash'};
    my $body;
    if (not null $cv->ROOT) {
        my $lineseq = $cv->ROOT->first;
        if ($lineseq->name eq "lineseq") {
            my @ops;
            for(my$o=$lineseq->first; $$o; $o=$o->sibling) {
                push @ops, $o;
            }
            $body = $self->lineseq(undef, @ops).";";
            my $scope_en = $self->find_scope_en($lineseq);
            if (defined $scope_en) {
                my $subs = join"", $self->seq_subs($scope_en);
                $body .= ";\n$subs" if length($subs);
            }
        }
        else {
            $body = $self->deparse($cv->ROOT->first, 0);
        }
    }
    else {
        my $sv = $cv->const_sv;
        if ($$sv) {
            # uh-oh. inlinable sub... format it differently
            return $proto . "{ " . $self->const($sv, 0) . " }\n";
        } else { # XSUB? (or just a declaration)
            return "$proto;\n";
        }
    }
    return $proto ."{\n\t$body\n\b}" ."\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;
    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, 0);
        }
        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 maybe_local {
    my $self = shift;
    my($op, $cx, $text) = @_;
    my $our_intro = ($op->name =~ /^(gv|rv2)[ash]v$/) ? OPpOUR_INTRO : 0;
    if ($op->private & (OPpLVAL_INTRO|$our_intro)
        and not $self->{'avoid_local'}{$$op}) {
        my $our_local = ($op->private & OPpLVAL_INTRO) ? "local" : "our";
        if( $our_local eq 'our' ) {
            if ( $text !~ /^\W(\w+::)*\w+\z/
             and !utf8::decode($text) || $text !~ /^\W(\w+::)*\w+\z/
            ) {
                die "Unexpected our($text)\n";
            }
            $text =~ s/(\w+::)+//;
        }
        if (want_scalar($op)) {
            return "$our_local $text";
        } else {
            return $self->maybe_parens_func("$our_local", $text, $cx, 16);
        }
    } else {
        return $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, $text) = @_;
    if ($op->private & OPpLVAL_INTRO and not $self->{'avoid_local'}{$$op}) {
        my $my = $op->private & OPpPAD_STATE
            ? $self->keyword("state")
            : "my";
        if (want_scalar($op)) {
            return "$my $text";
        } else {
            return $self->maybe_parens_func($my, $text, $cx, 16);
        }
    } else {
        return $text;
    }
}

# The following OPs don't have functions:

# pp_padany -- does not exist after parsing

sub AUTOLOAD {
    if ($AUTOLOAD =~ s/^.*::pp_//) {
        warn "unexpected OP_".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, $root, @ops) = @_;
    my($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 $body = join(";\n", grep {length} @exprs);
    my $subs = "";
    if (defined $root && defined $limit_seq && !$self->{'in_format'}) {
        $subs = join "\n", $self->seq_subs($limit_seq);
    }
    return join(";\n", 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") {
                $name = "while";
            } elsif ($name eq "or") {
                $name = "until";
            } else { # no conditional -> while 1 or until 0
                return $self->deparse($top->first, 1) . " 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)
        return "do {\n\t" . $self->lineseq($op, @kids) . "\n\b}";
    } else {
        my $lineseq = $self->lineseq($op, @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 { 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;
        }
        $expr .= $self->deparse($kids[$i], (@kids != 1)/2);
        $expr =~ s/;\n?\z//;
        $callback->($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 $gv = shift;
Carp::confess() unless ref($gv) eq "B::GV";
    my $stash = $gv->STASH->NAME;
    my $name = $gv->SAFENAME;
    if ($stash eq 'main' && $name =~ /^::/) {
        $stash = '::';
    }
    elsif (($stash eq 'main' && $globalnames{$name})
        or ($stash eq $self->{'curstash'} && !$globalnames{$name}
            && ($stash eq 'main' || $name !~ /::/))
        or $name =~ /^[^A-Za-z_:]/)
    {
        $stash = "";
    } else {
        $stash = $stash . "::";
    }
    if ($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, it may need to be
# fully-qualified.
sub stash_variable {
    my ($self, $prefix, $name, $cx) = @_;

    return "$prefix$name" if $name =~ /::/;

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

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

    my $v = ($prefix eq '$#' ? '@' : $prefix) . $name;
    return $prefix .$self->{'curstash'}.'::'. $name if $self->lex_in_scope($v);
    return "$prefix$name";
}

sub lex_in_scope {
    my ($self, $name) = @_;
    $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";
            next if $ns[$i]->FLAGS & SVpad_OUR;  # Skip "our" vars
            if (class($ns[$i]) eq "PV") {
                # Probably that pesky lexical @_
                next;
            }
            my $name = $ns[$i]->PVX;
            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 @{$self->{'curcvlex'}{$name}}, [$seq_st, $seq_en];
        }
    }
}

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 = $op->cop_seq;
    # If we have nephews, then our sequence number indicates
    # the cop_seq of the end of some sort of scope.
    if (class($op->sibling) ne "NULL" && $op->sibling->flags & OPf_KIDS
        and my $nseq = $self->find_scope_st($op->sibling) ) {
        $seq = $nseq;
    }
    $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 $seq;
    while (scalar(@{$self->{'subs_todo'}})
           and $seq > $self->{'subs_todo'}[0][0]) {
        push @text, $self->next_todo;
    }
    return @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;
    push @text, $self->cop_subs($op);
    my $stash = $op->stashpv;
    if ($stash ne $self->{'curstash'}) {
        push @text, "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 $warning_bits) {
        push @text, declare_warnings($self->{'warnings'}, $warning_bits);
        $self->{'warnings'} = $warning_bits;
    }

    my $hints = $] < 5.008009 ? $op->private : $op->hints;
    if ($self->{'hints'} != $hints) {
        push @text, declare_hints($self->{'hints'}, $hints);
        $self->{'hints'} = $hints;
    }

    # hack to check that the hint hash hasn't changed
    if ($] > 5.009 &&
        "@{[sort %{$self->{'hinthash'} || {}}]}"
        ne "@{[sort %{$op->hints_hash->HASH || {}}]}") {
        push @text, declare_hinthash($self->{'hinthash'}, $op->hints_hash->HASH, $self->{indent_size});
        $self->{'hinthash'} = $op->hints_hash->HASH;
    }

    # 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'}) {
        push @text, "\f#line " . $op->line .
          ' "' . $op->file, qq'"\n';
    }

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

    return join("", @text);
}

sub declare_warnings {
    my ($from, $to) = @_;
    if (($to & WARN_MASK) eq (warnings::bits("all") & WARN_MASK)) {
        return "use warnings;\n";
    }
    elsif (($to & WARN_MASK) eq ("\0"x length($to) & WARN_MASK)) {
        return "no warnings;\n";
    }
    return "BEGIN {\${^WARNING_BITS} = ".perlstring($to)."}\n";
}

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

sub declare_hinthash {
    my ($from, $to, $indent) = @_;
    my @decls;
    for my $key (keys %$to) {
        next if $ignored_hints{$key};
        if (!defined $from->{$key} or $from->{$key} ne $to->{$key}) {
            push @decls, qq(\$^H{'$key'} = q($to->{$key}););
        }
    }
    for my $key (keys %$from) {
        next if $ignored_hints{$key};
        if (!exists $to->{$key}) {
            push @decls, qq(delete \$^H{'$key'};);
        }
    }
    @decls or return '';
    return join("\n" . (" " x $indent), "BEGIN {", @decls) . "\n}\n";
}

sub hint_pragmas {
    my ($bits) = @_;
    my @pragmas;
    push @pragmas, "integer" if $bits & 0x1;
    push @pragmas, "strict 'refs'" if $bits & 0x2;
    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 keyword {
    my $self = shift;
    my $name = shift;
    return $name if $name =~ /^CORE::/; # just in case
    if (exists $feature_keywords{$name}) {
        return "CORE::$name"
         if !$self->{'hinthash'}
         || !$self->{'hinthash'}{"feature_$feature_keywords{$name}"}
    }
    if (
      $name !~ /^(?:chom?p|do|exec|glob|s(?:elect|ystem))\z/
       && !defined eval{prototype "CORE::$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 {
    my $self = shift;
    my($op, $cx, $name) = @_;
    if ($cx >= 1) {
        return "()";
    }
    else {
        return "();";
    }
}
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" : "$name$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) }

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) {
        $self->pfixop($op, $cx, $self->keyword("not")." ", 4);
    } else {
        $self->pfixop($op, $cx, "!", 21);       
    }
}

sub unop {
    my $self = shift;
    my($op, $cx, $name) = @_;
    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($builtinname)
           && prototype($builtinname) =~ /^;?\*/
           && $kid->name eq "rv2gv") {
            $kid = $kid->first;
        }

        return $self->maybe_parens_unop($name, $kid, $cx);
    } else {
        return $self->keyword($name)
          . ($op->flags & OPf_SPECIAL ? "()" : "");
    }
}

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 { 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 { unop(@_, "do") }
sub pp_entereval {
    unop(
      @_,
      $_[1]->private & OPpEVAL_BYTES ? $_[0]->keyword('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 $arg;
    if ($op->private & OPpEXISTS_SUB) {
        # Checking for the existence of a subroutine
        return $self->maybe_parens_func("exists",
                                $self->pp_rv2cv($op->first, 16), $cx, 16);
    }
    if ($op->flags & OPf_SPECIAL) {
        # Array element, not hash element
        return $self->maybe_parens_func("exists",
                                $self->pp_aelem($op->first, 16), $cx, 16);
    }
    return $self->maybe_parens_func("exists", $self->pp_helem($op->first, 16),
                                    $cx, 16);
}

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

sub pp_require {
    my $self = shift;
    my($op, $cx) = @_;
    my $opname = $op->flags & OPf_SPECIAL ? 'CORE::require' : 'require';
    if (class($op) eq "UNOP" and $op->first->name eq "const"
        and $op->first->private & OPpCONST_BARE)
    {
        my $name = $self->const_sv($op->first)->PV;
        $name =~ s[/][::]g;
        $name =~ s/\.pm//g;
        return "$opname $name";
    } else {    
        $self->unop($op, $cx, $op->first->private & OPpCONST_NOVER ? "no" : $opname);
    }
}

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") {
        $kid = $kid->first;
        if (!null($kid->sibling) and
                 $kid->sibling->name eq "anoncode") {
            return $self->e_anoncode({ code => $self->padval($kid->sibling->targ) });
        } elsif ($kid->name eq "pushmark") {
            my $sib_name = $kid->sibling->name;
            if ($sib_name =~ /^(pad|rv2)[ah]v$/
                and not $kid->sibling->flags & OPf_REF)
            {
                # The @a in \(@a) isn't in ref context, but only when the
                # parens are there.
                return "\\(" . $self->pp_list($op->first) . ")";
            } elsif ($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";
            }
        }
    }
    $self->pfixop($op, $cx, "\\", 20);
}

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

sub pp_srefgen { pp_refgen(@_) }

sub pp_readline {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first;
    $kid = $kid->first if $kid->name eq "rv2gv"; # <$fh>
    return "<" . $self->deparse($kid, 1) . ">" if is_scalar($kid);
    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 loopex {
    my $self = shift;
    my ($op, $cx, $name) = @_;
    if (class($op) eq "PVOP") {
        return "$name " . $op->pv;
    } elsif (class($op) eq "OP") {
        return $name;
    } elsif (class($op) eq "UNOP") {
        # Note -- loop exits are actually exempt from the
        # looks-like-a-func rule, but a few extra parens won't hurt
        return $self->maybe_parens_unop($name, $op->first, $cx);
    }
}

sub pp_last { loopex(@_, "last") }
sub pp_next { loopex(@_, "next") }
sub pp_redo { loopex(@_, "redo") }
sub pp_goto { loopex(@_, "goto") }
sub pp_dump { loopex(@_, $_[0]->keyword("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(); for the sake of clarity, give'em all parens
        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,
             'bit_or' => 12, 'bit_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,
              'add=' => 7, 'i_add=' => 7,
              'subtract=' => 7, 'i_subtract=' => 7,
              'concat=' => 7,
              'left_shift=' => 7, 'right_shift=' => 7,
              'bit_and=' => 7,
              'bit_or=' => 7, 'bit_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);
    }
    $left = $self->deparse_binop_left($op, $left, $prec);
    $left = "($left)" if $flags & LIST_CONTEXT
                && $left !~ /^(my|our|local|)[\@\(]/;
    $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) }

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 { 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 { 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) {
        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->first->name ne "concat") {
        $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);
}

# `x' is weird when the left arg is a list
sub pp_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
        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 {
        $left = $self->deparse_binop_left($op, $left, $prec);
    }
    $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 = $op->first->sibling;
    if ($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 listop {
    my $self = shift;
    my($op, $cx, $name) = @_;
    my(@exprs);
    my $parens = ($cx >= 5) || $self->{'parens'};
    my $kid = $op->first->sibling;
    return $self->keyword($name) if null $kid;
    my $first;
    $name = "socketpair" if $name eq "sockpair";
    my $fullname = $self->keyword($name);
    my $proto = prototype("CORE::$name");
    if (defined $proto
        && $proto =~ /^;?\*/
        && $kid->name eq "rv2gv") {
        $first = $self->deparse($kid->first, 6);
    }
    else {
        $first = $self->deparse($kid, 6);
    }
    if ($name eq "chmod" && $first =~ /^\d+$/) {
        $first = sprintf("%#o", $first);
    }
    $first = "+$first" if not $parens and substr($first, 0, 1) eq "(";
    push @exprs, $first;
    $kid = $kid->sibling;
    if (defined $proto && $proto =~ /^\*\*/ && $kid->name eq "rv2gv") {
        push @exprs, $self->deparse($kid->first, 6);
        $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) {
        return "$fullname(" . join(", ", @exprs) . ")";
    } else {
        return "$fullname " . join(", ", @exprs);
    }
}

sub pp_bless { listop(@_, "bless") }
sub pp_atan2 { maybe_targmy(@_, \&listop, "atan2") }
sub pp_substr { maybe_local(@_, listop(@_, "substr")) }
sub pp_vec { maybe_local(@_, listop(@_, "vec")) }
sub pp_index { maybe_targmy(@_, \&listop, "index") }
sub pp_rindex { maybe_targmy(@_, \&listop, "rindex") }
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") }
# Actually, return is exempt from the LLAFR (see examples in this very
# module!), but for consistency's sake, ignore that fact
sub pp_return { listop(@_, "return") }
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(@_, "sockpair") }
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(@_, \&listop, "system") }
sub pp_exec { maybe_targmy(@_, \&listop, "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 $text = $self->dq($op->first->sibling);  # skip pushmark
    my $keyword =
        $op->flags & OPf_SPECIAL ? 'glob' : $self->keyword('glob');
    if ($text =~ /^\$?(\w|::|\`)+$/ # could look like a readline
        or $keyword =~ /^CORE::/
        or $text =~ /[<>]/) {
        return "$keyword(" . single_delim('qq', '"', $text) . ')';
    } else {
        return '<' . $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"
      && $op->first->sibling->name eq 'entersub'
    ) {
        # We cannot say sort foo(bar), as foo will be interpreted as a
        # comparison routine.  We have to say sort(...) in that case.
        return "$name2($args)";
    } else {
        return $self->maybe_parens_func($name2, $args, $cx, 5);
    }

}

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) . ", ";
    }
    $kid = $kid->sibling;
    for (; !null($kid); $kid = $kid->sibling) {
        $expr = $self->deparse($kid, 6);
        push @exprs, $expr if defined $expr;
    }
    return $self->maybe_parens_func($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") }

sub pp_list {
    my $self = shift;
    my($op, $cx) = @_;
    my($expr, @exprs);
    my $kid = $op->first->sibling; # skip pushmark
    return '' if class($kid) eq 'NULL';
    my $lop;
    my $local = "either"; # could be local(...), my(...), state(...) or our(...)
    for ($lop = $kid; !null($lop); $lop = $lop->sibling) {
        # This assumes that no other private flags equal 128, and that
        # OPs that store things other than flags in their op_private,
        # like OP_AELEMFAST, won't be immediate children of a list.
        #
        # OP_ENTERSUB can break this logic, so check for it.
        # I suspect that open and exit can too.

        if (!($lop->private & (OPpLVAL_INTRO|OPpOUR_INTRO)
                or $lop->name eq "undef")
            or $lop->name eq "entersub"
            or $lop->name eq "exit"
            or $lop->name eq "open")
        {
            $local = ""; # or not
            last;
        }
        if ($lop->name =~ /^pad[ash]v$/) {
            if ($lop->private & OPpPAD_STATE) { # state()
                ($local = "", last) if $local =~ /^(?:local|our|my)$/;
                $local = "state";
            } else { # my()
                ($local = "", last) if $local =~ /^(?:local|our|state)$/;
                $local = "my";
            }
        } elsif ($lop->name =~ /^(gv|rv2)[ash]v$/
                        && $lop->private & OPpOUR_INTRO
                or $lop->name eq "null" && $lop->first->name eq "gvsv"
                        && $lop->first->private & OPpOUR_INTRO) { # our()
            ($local = "", last) if $local =~ /^(?:my|local|state)$/;
            $local = "our";
        } elsif ($lop->name ne "undef"
                # specifically avoid the "reverse sort" optimisation,
                # where "reverse" is nullified
                && !($lop->name eq 'sort' && ($lop->flags & OPpSORT_REVERSE)))
        {
            # local()
            ($local = "", last) if $local =~ /^(?:my|our|state)$/;
            $local = "local";
        }
    }
    $local = "" if $local eq "either"; # no point if it's all undefs
    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) {
        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 $head = "if ($cond) {\n\t$true\n\b}";
    my @elsifs;
    while (!null($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);
        push @elsifs, "elsif ($newcond) {\n\t$newtrue\n\b}";
    }
    if (!null($false)) {
        $false = $cuddle . "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;

    return $self->deparse($true, $cx);
}

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 $cond = undef;
    if ($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 $var) {
            if (($enter->flags & OPf_SPECIAL) && ($] < 5.009)) {
                # thread special var, under 5005threads
                $var = $self->pp_threadsv($enter, 1);
            } else { # regular my() variable
                $var = $self->pp_padsv($enter, 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);
        }
        $body = $kid->first->first->sibling; # skip OP_AND and OP_ITER
        if (!is_state $body->first and $body->first->name ne "stub") {
            confess unless $var eq '$_';
            $body = $body->first;
            return $self->deparse($body, 2) . " foreach ($ary)";
        }
        $head = "foreach $var ($ary) ";
    } elsif ($kid->name eq "null") { # while/until
        $kid = $kid->first;
        my $name = {"and" => "while", "or" => "until"}->{$kid->name};
        $cond = $self->deparse($kid->first, 1);
        $head = "$name ($cond) ";
        $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;
    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, @states);
        if (defined $cond and not is_scope $cont and $self->{'expand'} < 3) {
            $head = "for ($init; $cond; " . $self->deparse($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) {
            $head = "for ($init; $cond;) ";
        }
        $cont = "\cK";
        $body = $self->deparse($body, 0);
    }
    $body =~ s/;?$/;\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}";
}

BEGIN { for (qw[ const stringify rv2sv list glob ]) {
    eval "sub OP_\U$_ () { " . opnumber($_) . "}"
}}

sub pp_null {
    my $self = shift;
    my($op, $cx) = @_;
    if (class($op) eq "OP") {
        # old value is lost
        return $self->{'ex_const'} if $op->targ == OP_CONST;
    } elsif ($op->first->name eq "pushmark") {
        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 eq "trans" 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 "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) = @_;
    return $self->maybe_my($op, $cx, $self->padname($op->targ));
}

sub pp_padav { pp_padsv(@_) }
sub pp_padhv { pp_padsv(@_) }

my @threadsv_names = B::threadsv_names;
sub pp_threadsv {
    my $self = shift;
    my($op, $cx) = @_;
    return $self->maybe_local($op, $cx, "\$" .  $threadsv_names[$op->targ]);
}

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 $self->gv_name($gv);
}

sub pp_aelemfast_lex {
    my $self = shift;
    my($op, $cx) = @_;
    my $name = $self->padname($op->targ);
    $name =~ s/^@/\$/;
    return $name . "[" .  ($op->private + $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 = $self->gv_name($gv);
    $name = $self->{'curstash'}."::$name"
        if $name !~ /::/ && $self->lex_in_scope('@'.$name);
    $name = '$' . $name;
    return $name . "[" .  ($op->private + $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, $self->deparse($kid, 0), $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_rv2hv { maybe_local(@_, rv2x(@_, "%")) }
sub pp_rv2gv { maybe_local(@_, rv2x(@_, "*")) }

# 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 eq 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/) {
        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 $kid->name eq "gv";
        return 0 if is_scalar($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 = $self->gv_name($self->gv_or_padgv($array));
        if ($array !~ /::/) {
            my $prefix = ($left eq '[' ? '@' : '%');
            $array = $self->{curstash}.'::'.$array
                if $self->lex_in_scope($prefix . $array);
        }
        return $array;
    } elsif (!$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 . $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;
    }

}

sub pp_aelem { maybe_local(@_, elem(@_, "[", "]", "padav")) }
sub pp_helem { maybe_local(@_, elem(@_, "{", "}", "padhv")) }

sub pp_gelem {
    my $self = shift;
    my($op, $cx) = @_;
    my($glob, $part) = ($op->first, $op->last);
    $glob = $glob->first; # skip rv2gv
    $glob = $glob->first if $glob->name eq "rv2gv"; # this one's a bug
    my $scope = is_scope($glob);
    $glob = $self->deparse($glob, 0);
    $part = $self->deparse($part, 1);
    return "*" . ($scope ? "{$glob}" : $glob) . "{$part}";
}

sub slice {
    my $self = shift;
    my ($op, $cx, $left, $right, $regname, $padname) = @_;
    my $last;
    my(@elems, $kid, $array, $list);
    if (class($op) eq "LISTOP") {
        $last = $op->last;
    } else { # ex-hslice inside delete()
        for ($kid = $op->first; !null $kid->sibling; $kid = $kid->sibling) {}
        $last = $kid;
    }
    $array = $last;
    $array = $array->first
        if $array->name eq $regname or $array->name eq "null";
    $array = $self->elem_or_slice_array_name($array,$left,$padname,0);
    $kid = $op->first->sibling; # skip pushmark
    if ($kid->name eq "list") {
        $kid = $kid->first->sibling; # skip list, pushmark
        for (; !null $kid; $kid = $kid->sibling) {
            push @elems, $self->deparse($kid, 6);
        }
        $list = join(", ", @elems);
    } else {
        $list = $self->elem_or_slice_single_index($kid);
    }
    return "\@" . $array . $left . $list . $right;
}

sub pp_aslice { maybe_local(@_, slice(@_, "[", "]", "rv2av", "padav")) }
sub pp_hslice { maybe_local(@_, slice(@_, "{", "}", "rv2hv", "padhv")) }

sub pp_lslice {
    my $self = shift;
    my($op, $cx) = @_;
    my $idx = $op->first;
    my $list = $op->last;
    my(@elems, $kid);
    $list = $self->deparse($list, 1);
    $idx = $self->deparse($idx, 1);
    return "($list)" . "[$idx]";
}

sub want_scalar {
    my $op = shift;
    return ($op->flags & OPf_WANT) == OPf_WANT_SCALAR;
}

sub want_list {
    my $op = shift;
    return ($op->flags & OPf_WANT) == OPf_WANT_LIST;
}

sub _method {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first->sibling; # skip pushmark
    my($meth, $obj, @exprs);
    if ($kid->name eq "list" and want_list $kid) {
        # When an indirect object isn't a bareword but the args are in
        # parens, the parens aren't part of the method syntax (the LLAFR
        # doesn't apply), but they make a list with OPf_PARENS set that
        # doesn't get flattened by the append_elem that adds the method,
        # making a (object, arg1, arg2, ...) list where the object
        # usually is. This can be distinguished from
        # `($obj, $arg1, $arg2)->meth()' (which is legal if $arg2 is an
        # object) because in the later the list is in scalar context
        # as the left side of -> always is, while in the former
        # the list is in list context as method arguments always are.
        # (Good thing there aren't method prototypes!)
        $meth = $kid->sibling;
        $kid = $kid->first->sibling; # skip pushmark
        $obj = $kid;
        $kid = $kid->sibling;
        for (; not null $kid; $kid = $kid->sibling) {
            push @exprs, $kid;
        }
    } else {
        $obj = $kid;
        $kid = $kid->sibling;
        for (; !null ($kid->sibling) && $kid->name!~/^method(?:_named)?\z/;
              $kid = $kid->sibling) {
            push @exprs, $kid
        }
        $meth = $kid;
    }

    if ($meth->name eq "method_named") {
        $meth = $self->const_sv($meth)->PV;
    } else {
        $meth = $meth->first;
        if ($meth->name eq "const") {
            # As of 5.005_58, this case is probably obsoleted by the
            # method_named case above
            $meth = $self->const_sv($meth)->PV; # needs to be bare
        }
    }

    return { method => $meth, variable_method => ref($meth),
             object => $obj, args => \@exprs  };
}

# compat function only
sub method {
    my $self = shift;
    my $info = $self->_method(@_);
    return $self->e_method( $self->_method(@_) );
}

sub e_method {
    my ($self, $info) = @_;
    my $obj = $self->deparse($info->{object}, 24);

    my $meth = $info->{method};
    $meth = $self->deparse($meth, 1) if $info->{variable_method};
    my $args = join(", ", map { $self->deparse($_, 6) } @{$info->{args}} );
    my $kid = $obj . "->" . $meth;
    if (length $args) {
        return $kid . "(" . $args . ")"; # parens mandatory
    } else {
        return $kid;
    }
}

# returns "&" if the prototype doesn't match the args,
# or ("", $args_after_prototype_demunging) if it does.
sub check_proto {
    my $self = shift;
    return "&" if $self->{'noproto'};
    my($proto, @args) = @_;
    my($arg, $real);
    my $doneok = 0;
    my @reals;
    # An unbackslashed @ or % gobbles up the rest of the args
    1 while $proto =~ s/(?<!\\)([@%])[^\]]+$/$1/;
    while ($proto) {
        $proto =~ s/^(\\?[\$\@&%*_]|\\\[[\$\@&%*]+\]|;)//;
        my $chr = $1;
        if ($chr eq "") {
            return "&" if @args;
        } elsif ($chr eq ";") {
            $doneok = 1;
        } elsif ($chr eq "@" or $chr eq "%") {
            push @reals, map($self->deparse($_, 6), @args);
            @args = ();
        } else {
            $arg = shift @args;
            last unless $arg;
            if ($chr eq "\$" || $chr eq "_") {
                if (want_scalar $arg) {
                    push @reals, $self->deparse($arg, 6);
                } else {
                    return "&";
                }
            } elsif ($chr eq "&") {
                if ($arg->name =~ /^(s?refgen|undef)$/) {
                    push @reals, $self->deparse($arg, 6);
                } else {
                    return "&";
                }
            } elsif ($chr eq "*") {
                if ($arg->name =~ /^s?refgen$/
                    and $arg->first->first->name eq "rv2gv")
                  {
                      $real = $arg->first->first; # skip refgen, null
                      if ($real->first->name eq "gv") {
                          push @reals, $self->deparse($real, 6);
                      } else {
                          push @reals, $self->deparse($real->first, 6);
                      }
                  } else {
                      return "&";
                  }
            } elsif (substr($chr, 0, 1) eq "\\") {
                $chr =~ tr/\\[]//d;
                if ($arg->name =~ /^s?refgen$/ and
                    !null($real = $arg->first) and
                    ($chr =~ /\$/ && is_scalar($real->first)
                     or ($chr =~ /@/
                         && class($real->first->sibling) ne 'NULL'
                         && $real->first->sibling->name
                         =~ /^(rv2|pad)av$/)
                     or ($chr =~ /%/
                         && class($real->first->sibling) ne 'NULL'
                         && $real->first->sibling->name
                         =~ /^(rv2|pad)hv$/)
                     #or ($chr =~ /&/ # This doesn't work
                     #   && $real->first->name eq "rv2cv")
                     or ($chr =~ /\*/
                         && $real->first->name eq "rv2gv")))
                  {
                      push @reals, $self->deparse($real, 6);
                  } else {
                      return "&";
                  }
            }
       }
    }
    return "&" if $proto and !$doneok; # too few args and no `;'
    return "&" if @args;               # too many args
    return ("", join ", ", @reals);
}

sub pp_entersub {
    my $self = shift;
    my($op, $cx) = @_;
    return $self->e_method($self->_method($op, $cx))
        unless null $op->first->sibling;
    my $prefix = "";
    my $amper = "";
    my($kid, @exprs);
    if ($op->flags & OPf_SPECIAL && !($op->flags & OPf_MOD)) {
        $prefix = "do ";
    } elsif ($op->private & OPpENTERSUB_AMPER) {
        $amper = "&";
    }
    $kid = $op->first;
    $kid = $kid->first->sibling; # skip ex-list, pushmark
    for (; not null $kid->sibling; $kid = $kid->sibling) {
        push @exprs, $kid;
    }
    my $simple = 0;
    my $proto = undef;
    if (is_scope($kid)) {
        $amper = "&";
        $kid = "{" . $self->deparse($kid, 0) . "}";
    } elsif ($kid->first->name eq "gv") {
        my $gv = $self->gv_or_padgv($kid->first);
        if (class($gv->CV) ne "SPECIAL") {
            $proto = $gv->CV->PV if $gv->CV->FLAGS & SVf_POK;
        }
        $simple = 1; # only calls of named functions can be prototyped
        $kid = $self->deparse($kid, 24);
        if (!$amper) {
            if ($kid eq 'main::') {
                $kid = '::';
            } elsif ($kid !~ /^(?:\w|::)(?:[\w\d]|::(?!\z))*\z/) {
                $kid = single_delim("q", "'", $kid) . '->';
            }
        }
    } elsif (is_scalar ($kid->first) && $kid->first->name ne 'rv2cv') {
        $amper = "&";
        $kid = $self->deparse($kid, 24);
    } else {
        $prefix = "";
        my $arrow = is_subscriptable($kid->first) ? "" : "->";
        $kid = $self->deparse($kid, 24) . $arrow;
    }

    # Doesn't matter how many prototypes there are, if
    # they haven't happened yet!
    my $declared;
    {
        no strict 'refs';
        no warnings 'uninitialized';
        $declared = exists $self->{'subs_declared'}{$kid}
            || (
                 defined &{ ${$self->{'curstash'}."::"}{$kid} }
                 && !exists
                     $self->{'subs_deparsed'}{$self->{'curstash'}."::".$kid}
                 && defined prototype $self->{'curstash'}."::".$kid
               );
        if (!$declared && defined($proto)) {
            # Avoid "too early to check prototype" warning
            ($amper, $proto) = ('&');
        }
    }

    my $args;
    if ($declared and defined $proto and not $amper) {
        ($amper, $args) = $self->check_proto($proto, @exprs);
        if ($amper eq "&") {
            $args = join(", ", map($self->deparse($_, 6), @exprs));
        }
    } else {
        $args = join(", ", map($self->deparse($_, 6), @exprs));
    }
    if ($prefix or $amper) {
        if ($op->flags & OPf_STACKED) {
            return $prefix . $amper . $kid . "(" . $args . ")";
        } else {
            return $prefix . $amper. $kid;
        }
    } else {
        # It's a syntax error to call CORE::GLOBAL::foo with a prefix,
        # so it must have been translated from a keyword call. Translate
        # it back.
        $kid =~ s/^CORE::GLOBAL:://;

        my $dproto = defined($proto) ? $proto : "undefined";
        if (!$declared) {
            return "$kid(" . $args . ")";
        } elsif ($dproto eq "") {
            return $kid;
        } elsif ($dproto eq "\$" and is_scalar($exprs[0])) {
            # is_scalar is an excessively conservative test here:
            # really, we should be comparing to the precedence of the
            # top operator of $exprs[0] (ala unop()), but that would
            # take some major code restructuring to do right.
            return $self->maybe_parens_func($kid, $args, $cx, 16);
        } elsif ($dproto ne '$' and defined($proto) || $simple) { #'
            return $self->maybe_parens_func($kid, $args, $cx, 5);
        } else {
            return "$kid(" . $args . ")";
        }
    }
}

sub pp_enterwrite { unop(@_, "write") }

# escape things that cause interpolation in double quotes,
# but not character escapes
sub uninterp {
    my($str) = @_;
    $str =~ s/(^|\G|[^\\])((?:\\\\)*)([\$\@]|\\[uUlLQE])/$1$2\\$3/g;
    return $str;
}

{
my $bal;
BEGIN {
    use re "eval";
    # Matches any string which is balanced with respect to {braces}
    $bal = qr(
      (?:
        [^\\{}]
      | \\\\
      | \\[{}]
      | \{(??{$bal})\}
      )*
    )x;
}

# the same, but treat $|, $), $( and $ at the end of the string differently
sub re_uninterp {
    my($str) = @_;

    $str =~ s/
          ( ^|\G                  # $1
          | [^\\]
          )

          (                       # $2
            (?:\\\\)*
          )

          (                       # $3
            (\(\?\??\{$bal\}\))   # $4
          | [\$\@]
            (?!\||\)|\(|$)
          | \\[uUlLQE]
          )

        /defined($4) && length($4) ? "$1$2$4" : "$1$2\\$3"/xeg;

    return $str;
}

# This is for regular expressions with the /x modifier
# We have to leave comments unmangled.
sub re_uninterp_extended {
    my($str) = @_;

    $str =~ s/
          ( ^|\G                  # $1
          | [^\\]
          )

          (                       # $2
            (?:\\\\)*
          )

          (                       # $3
            ( \(\?\??\{$bal\}\)   # $4  (skip over (?{}) and (??{}) blocks)
            | \#[^\n]*            #     (skip over comments)
            )
          | [\$\@]
            (?!\||\)|\(|$|\s)
          | \\[uUlLQE]
          )

        /defined($4) && length($4) ? "$1$2$4" : "$1$2\\$3"/xeg;

    return $str;
}
}

my %unctrl = # portable to to EBCDIC
    (
     "\c@" => '\c@',    # unused
     "\cA" => '\cA',
     "\cB" => '\cB',
     "\cC" => '\cC',
     "\cD" => '\cD',
     "\cE" => '\cE',
     "\cF" => '\cF',
     "\cG" => '\cG',
     "\cH" => '\cH',
     "\cI" => '\cI',
     "\cJ" => '\cJ',
     "\cK" => '\cK',
     "\cL" => '\cL',
     "\cM" => '\cM',
     "\cN" => '\cN',
     "\cO" => '\cO',
     "\cP" => '\cP',
     "\cQ" => '\cQ',
     "\cR" => '\cR',
     "\cS" => '\cS',
     "\cT" => '\cT',
     "\cU" => '\cU',
     "\cV" => '\cV',
     "\cW" => '\cW',
     "\cX" => '\cX',
     "\cY" => '\cY',
     "\cZ" => '\cZ',
     "\c[" => '\c[',    # unused
     "\c\\" => '\c\\',  # unused
     "\c]" => '\c]',    # unused
     "\c_" => '\c_',    # unused
    );

# character escapes, but not delimiters that might need to be escaped
sub escape_str { # ASCII, UTF8
    my($str) = @_;
    $str =~ s/(.)/ord($1) > 255 ? sprintf("\\x{%x}", ord($1)) : $1/eg;
    $str =~ s/\a/\\a/g;
#    $str =~ s/\cH/\\b/g; # \b means something different in a regex
    $str =~ s/\t/\\t/g;
    $str =~ s/\n/\\n/g;
    $str =~ s/\e/\\e/g;
    $str =~ s/\f/\\f/g;
    $str =~ s/\r/\\r/g;
    $str =~ s/([\cA-\cZ])/$unctrl{$1}/ge;
    $str =~ s/([[:^print:]])/sprintf("\\%03o", ord($1))/ge;
    return $str;
}

# For regexes with the /x modifier.
# Leave whitespace unmangled.
sub escape_extended_re {
    my($str) = @_;
    $str =~ s/(.)/ord($1) > 255 ? sprintf("\\x{%x}", ord($1)) : $1/eg;
    $str =~ s/([[:^print:]])/
        ($1 =~ y! \t\n!!) ? $1 : sprintf("\\%03o", ord($1))/ge;
    $str =~ s/\n/\n\f/g;
    return $str;
}

# Don't do this for regexen
sub unback {
    my($str) = @_;
    $str =~ s/\\/\\\\/g;
    return $str;
}

# Remove backslashes which precede literal control characters,
# to avoid creating ambiguity when we escape the latter.
sub re_unback {
    my($str) = @_;

    # the insane complexity here is due to the behaviour of "\c\"
    $str =~ s/(^|[^\\]|\\c\\)(?<!\\c)\\(\\\\)*(?=[[:^print:]])/$1$2/g;
    return $str;
}

sub balanced_delim {
    my($str) = @_;
    my @str = split //, $str;
    my($ar, $open, $close, $fail, $c, $cnt, $last_bs);
    for $ar (['[',']'], ['(',')'], ['<','>'], ['{','}']) {
        ($open, $close) = @$ar;
        $fail = 0; $cnt = 0; $last_bs = 0;
        for $c (@str) {
            if ($c eq $open) {
                $fail = 1 if $last_bs;
                $cnt++;
            } elsif ($c eq $close) {
                $fail = 1 if $last_bs;
                $cnt--;
                if ($cnt < 0) {
                    # qq()() isn't ")("
                    $fail = 1;
                    last;
                }
            }
            $last_bs = $c eq '\\';
        }
        $fail = 1 if $cnt != 0;
        return ($open, "$open$str$close") if not $fail;
    }
    return ("", $str);
}

sub single_delim {
    my($q, $default, $str) = @_;
    return "$default$str$default" if $default and index($str, $default) == -1;
    if ($q ne 'qr') {
        (my $succeed, $str) = balanced_delim($str);
        return "$q$str" if $succeed;
    }
    for my $delim ('/', '"', '#') {
        return "$q$delim" . $str . $delim if index($str, $delim) == -1;
    }
    if ($default) {
        $str =~ s/$default/\\$default/g;
        return "$default$str$default";
    } else {
        $str =~ s[/][\\/]g;
        return "$q/$str/";
    }
}

my $max_prec;
BEGIN { $max_prec = int(0.999 + 8*length(pack("F", 42))*log(2)/log(10)); }

# Split a floating point number into an integer mantissa and a binary
# exponent. Assumes you've already made sure the number isn't zero or
# some weird infinity or NaN.
sub split_float {
    my($f) = @_;
    my $exponent = 0;
    if ($f == int($f)) {
        while ($f % 2 == 0) {
            $f /= 2;
            $exponent++;
        }
    } else {
        while ($f != int($f)) {
            $f *= 2;
            $exponent--;
        }
    }
    my $mantissa = sprintf("%.0f", $f);
    return ($mantissa, $exponent);
}

sub const {
    my $self = shift;
    my($sv, $cx) = @_;
    if ($self->{'use_dumper'}) {
        return $self->const_dumper($sv, $cx);
    }
    if (class($sv) eq "SPECIAL") {
        # sv_undef, sv_yes, sv_no
        return ('undef', '1', $self->maybe_parens("!1", $cx, 21))[$$sv-1];
    }
    if (class($sv) eq "NULL") {
       return 'undef';
    }
    # convert a version object into the "v1.2.3" string in its V magic
    if ($sv->FLAGS & SVs_RMG) {
        for (my $mg = $sv->MAGIC; $mg; $mg = $mg->MOREMAGIC) {
            return $mg->PTR if $mg->TYPE eq 'V';
        }
    }

    if ($sv->FLAGS & SVf_IOK) {
        my $str = $sv->int_value;
        $str = $self->maybe_parens($str, $cx, 21) if $str < 0;
        return $str;
    } elsif ($sv->FLAGS & SVf_NOK) {
        my $nv = $sv->NV;
        if ($nv == 0) {
            if (pack("F", $nv) eq pack("F", 0)) {
                # positive zero
                return "0";
            } else {
                # negative zero
                return $self->maybe_parens("-.0", $cx, 21);
            }
        } elsif (1/$nv == 0) {
            if ($nv > 0) {
                # positive infinity
                return $self->maybe_parens("9**9**9", $cx, 22);
            } else {
                # negative infinity
                return $self->maybe_parens("-9**9**9", $cx, 21);
            }
        } elsif ($nv != $nv) {
            # NaN
            if (pack("F", $nv) eq pack("F", sin(9**9**9))) {
                # the normal kind
                return "sin(9**9**9)";
            } elsif (pack("F", $nv) eq pack("F", -sin(9**9**9))) {
                # the inverted kind
                return $self->maybe_parens("-sin(9**9**9)", $cx, 21);
            } else {
                # some other kind
                my $hex = unpack("h*", pack("F", $nv));
                return qq'unpack("F", pack("h*", "$hex"))';
            }
        }
        # first, try the default stringification
        my $str = "$nv";
        if ($str != $nv) {
            # failing that, try using more precision
            $str = sprintf("%.${max_prec}g", $nv);
#           if (pack("F", $str) ne pack("F", $nv)) {
            if ($str != $nv) {
                # not representable in decimal with whatever sprintf()
                # and atof() Perl is using here.
                my($mant, $exp) = split_float($nv);
                return $self->maybe_parens("$mant * 2**$exp", $cx, 19);
            }
        }
        $str = $self->maybe_parens($str, $cx, 21) if $nv < 0;
        return $str;
    } elsif ($sv->FLAGS & SVf_ROK && $sv->can("RV")) {
        my $ref = $sv->RV;
        if (class($ref) eq "AV") {
            return "[" . $self->list_const(2, $ref->ARRAY) . "]";
        } elsif (class($ref) eq "HV") {
            my %hash = $ref->ARRAY;
            my @elts;
            for my $k (sort keys %hash) {
                push @elts, "$k => " . $self->const($hash{$k}, 6);
            }
            return "{" . join(", ", @elts) . "}";
        } elsif (class($ref) eq "CV") {
            return "sub " . $self->deparse_sub($ref);
        }
        if ($ref->FLAGS & SVs_SMG) {
            for (my $mg = $ref->MAGIC; $mg; $mg = $mg->MOREMAGIC) {
                if ($mg->TYPE eq 'r') {
                    my $re = re_uninterp(escape_str(re_unback($mg->precomp)));
                    return single_delim("qr", "", $re);
                }
            }
        }
        
        return $self->maybe_parens("\\" . $self->const($ref, 20), $cx, 20);
    } elsif ($sv->FLAGS & SVf_POK) {
        my $str = $sv->PV;
        if ($str =~ /[[:^print:]]/) {
            return single_delim("qq", '"', uninterp escape_str unback $str);
        } else {
            return single_delim("q", "'", unback $str);
        }
    } else {
        return "undef";
    }
}

sub const_dumper {
    my $self = shift;
    my($sv, $cx) = @_;
    my $ref = $sv->object_2svref();
    my $dumper = Data::Dumper->new([$$ref], ['$v']);
    $dumper->Purity(1)->Terse(1)->Deparse(1)->Indent(0)->Useqq(1)->Sortkeys(1);
    my $str = $dumper->Dump();
    if ($str =~ /^\$v/) {
        return '${my ' . $str . ' \$v}';
    } else {
        return $str;
    }
}

sub const_sv {
    my $self = shift;
    my $op = shift;
    my $sv = $op->sv;
    # the constant could be in the pad (under useithreads)
    $sv = $self->padval($op->targ) unless $$sv;
    return $sv;
}

sub pp_const {
    my $self = shift;
    my($op, $cx) = @_;
    if ($op->private & OPpCONST_ARYBASE) {
        return '$[';
    }
#    if ($op->private & OPpCONST_BARE) { # trouble with `=>' autoquoting
#       return $self->const_sv($op)->PV;
#    }
    my $sv = $self->const_sv($op);
    return $self->const($sv, $cx);
}

sub dq {
    my $self = shift;
    my $op = shift;
    my $type = $op->name;
    if ($type eq "const") {
        return '$[' if $op->private & OPpCONST_ARYBASE;
        return uninterp(escape_str(unback($self->const_sv($op)->as_string)));
    } elsif ($type eq "concat") {
        my $first = $self->dq($op->first);
        my $last  = $self->dq($op->last);

        # Disambiguate "${foo}bar", "${foo}{bar}", "${foo}[1]", "$foo\::bar"
        ($last =~ /^[A-Z\\\^\[\]_?]/ &&
            $first =~ s/([\$@])\^$/${1}{^}/)  # "${^}W" etc
            || ($last =~ /^[:'{\[\w_]/ && #'
                $first =~ s/([\$@])([A-Za-z_]\w*)$/${1}{$2}/);

        return $first . $last;
    } elsif ($type eq "uc") {
        return '\U' . $self->dq($op->first->sibling) . '\E';
    } elsif ($type eq "lc") {
        return '\L' . $self->dq($op->first->sibling) . '\E';
    } elsif ($type eq "ucfirst") {
        return '\u' . $self->dq($op->first->sibling);
    } elsif ($type eq "lcfirst") {
        return '\l' . $self->dq($op->first->sibling);
    } elsif ($type eq "quotemeta") {
        return '\Q' . $self->dq($op->first->sibling) . '\E';
    } elsif ($type eq "join") {
        return $self->deparse($op->last, 26); # was join($", @ary)
    } else {
        return $self->deparse($op, 26);
    }
}

sub pp_backtick {
    my $self = shift;
    my($op, $cx) = @_;
    # skip pushmark if it exists (readpipe() vs ``)
    my $child = $op->first->sibling->isa('B::NULL')
        ? $op->first : $op->first->sibling;
    if ($self->pure_string($child)) {
        return single_delim("qx", '`', $self->dq($child, 1));
    }
    unop($self, @_, "readpipe");
}

sub dquote {
    my $self = shift;
    my($op, $cx) = @_;
    my $kid = $op->first->sibling; # skip ex-stringify, pushmark
    return $self->deparse($kid, $cx) if $self->{'unquote'};
    $self->maybe_targmy($kid, $cx,
                        sub {single_delim("qq", '"', $self->dq($_[1]))});
}

# OP_STRINGIFY is a listop, but it only ever has one arg
sub pp_stringify { maybe_targmy(@_, \&dquote) }

# tr/// and s/// (and tr[][], tr[]//, tr###, etc)
# note that tr(from)/to/ is OK, but not tr/from/(to)
sub double_delim {
    my($from, $to) = @_;
    my($succeed, $delim);
    if ($from !~ m[/] and $to !~ m[/]) {
        return "/$from/$to/";
    } elsif (($succeed, $from) = balanced_delim($from) and $succeed) {
        if (($succeed, $to) = balanced_delim($to) and $succeed) {
            return "$from$to";
        } else {
            for $delim ('/', '"', '#') { # note no `'' -- s''' is special
                return "$from$delim$to$delim" if index($to, $delim) == -1;
            }
            $to =~ s[/][\\/]g;
            return "$from/$to/";
        }
    } else {
        for $delim ('/', '"', '#') { # note no '
            return "$delim$from$delim$to$delim"
                if index($to . $from, $delim) == -1;
        }
        $from =~ s[/][\\/]g;
        $to =~ s[/][\\/]g;
        return "/$from/$to/";   
    }
}

# Only used by tr///, so backslashes hyphens
sub pchr { # ASCII
    my($n) = @_;
    if ($n == ord '\\') {
        return '\\\\';
    } elsif ($n == ord "-") {
        return "\\-";
    } elsif ($n >= ord(' ') and $n <= ord('~')) {
        return chr($n);
    } elsif ($n == ord "\a") {
        return '\\a';
    } elsif ($n == ord "\b") {
        return '\\b';
    } elsif ($n == ord "\t") {
        return '\\t';
    } elsif ($n == ord "\n") {
        return '\\n';
    } elsif ($n == ord "\e") {
        return '\\e';
    } elsif ($n == ord "\f") {
        return '\\f';
    } elsif ($n == ord "\r") {
        return '\\r';
    } elsif ($n >= ord("\cA") and $n <= ord("\cZ")) {
        return '\\c' . chr(ord("@") + $n);
    } else {
#       return '\x' . sprintf("%02x", $n);
        return '\\' . sprintf("%03o", $n);
    }
}

sub collapse {
    my(@chars) = @_;
    my($str, $c, $tr) = ("");
    for ($c = 0; $c < @chars; $c++) {
        $tr = $chars[$c];
        $str .= pchr($tr);
        if ($c <= $#chars - 2 and $chars[$c + 1] == $tr + 1 and
            $chars[$c + 2] == $tr + 2)
        {
            for (; $c <= $#chars-1 and $chars[$c + 1] == $chars[$c] + 1; $c++)
              {}
            $str .= "-";
            $str .= pchr($chars[$c]);
        }
    }
    return $str;
}

sub tr_decode_byte {
    my($table, $flags) = @_;
    my(@table) = unpack("s*", $table);
    splice @table, 0x100, 1;   # Number of subsequent elements
    my($c, $tr, @from, @to, @delfrom, $delhyphen);
    if ($table[ord "-"] != -1 and
        $table[ord("-") - 1] == -1 || $table[ord("-") + 1] == -1)
    {
        $tr = $table[ord "-"];
        $table[ord "-"] = -1;
        if ($tr >= 0) {
            @from = ord("-");
            @to = $tr;
        } else { # -2 ==> delete
            $delhyphen = 1;
        }
    }
    for ($c = 0; $c < @table; $c++) {
        $tr = $table[$c];
        if ($tr >= 0) {
            push @from, $c; push @to, $tr;
        } elsif ($tr == -2) {
            push @delfrom, $c;
        }
    }
    @from = (@from, @delfrom);
    if ($flags & OPpTRANS_COMPLEMENT) {
        my @newfrom = ();
        my %from;
        @from{@from} = (1) x @from;
        for ($c = 0; $c < 256; $c++) {
            push @newfrom, $c unless $from{$c};
        }
        @from = @newfrom;
    }
    unless ($flags & OPpTRANS_DELETE || !@to) {
        pop @to while $#to and $to[$#to] == $to[$#to -1];
    }
    my($from, $to);
    $from = collapse(@from);
    $to = collapse(@to);
    $from .= "-" if $delhyphen;
    return ($from, $to);
}

sub tr_chr {
    my $x = shift;
    if ($x == ord "-") {
        return "\\-";
    } elsif ($x == ord "\\") {
        return "\\\\";
    } else {
        return chr $x;
    }
}

# XXX This doesn't yet handle all cases correctly either

sub tr_decode_utf8 {
    my($swash_hv, $flags) = @_;
    my %swash = $swash_hv->ARRAY;
    my $final = undef;
    $final = $swash{'FINAL'}->IV if exists $swash{'FINAL'};
    my $none = $swash{"NONE"}->IV;
    my $extra = $none + 1;
    my(@from, @delfrom, @to);
    my $line;
    foreach $line (split /\n/, $swash{'LIST'}->PV) {
        my($min, $max, $result) = split(/\t/, $line);
        $min = hex $min;
        if (length $max) {
            $max = hex $max;
        } else {
            $max = $min;
        }
        $result = hex $result;
        if ($result == $extra) {
            push @delfrom, [$min, $max];
        } else {
            push @from, [$min, $max];
            push @to, [$result, $result + $max - $min];
        }
    }
    for my $i (0 .. $#from) {
        if ($from[$i][0] == ord '-') {
            unshift @from, splice(@from, $i, 1);
            unshift @to, splice(@to, $i, 1);
            last;
        } elsif ($from[$i][1] == ord '-') {
            $from[$i][1]--;
            $to[$i][1]--;
            unshift @from, ord '-';
            unshift @to, ord '-';
            last;
        }
    }
    for my $i (0 .. $#delfrom) {
        if ($delfrom[$i][0] == ord '-') {
            push @delfrom, splice(@delfrom, $i, 1);
            last;
        } elsif ($delfrom[$i][1] == ord '-') {
            $delfrom[$i][1]--;
            push @delfrom, ord '-';
            last;
        }
    }
    if (defined $final and $to[$#to][1] != $final) {
        push @to, [$final, $final];
    }
    push @from, @delfrom;
    if ($flags & OPpTRANS_COMPLEMENT) {
        my @newfrom;
        my $next = 0;
        for my $i (0 .. $#from) {
            push @newfrom, [$next, $from[$i][0] - 1];
            $next = $from[$i][1] + 1;
        }
        @from = ();
        for my $range (@newfrom) {
            if ($range->[0] <= $range->[1]) {
                push @from, $range;
            }
        }
    }
    my($from, $to, $diff);
    for my $chunk (@from) {
        $diff = $chunk->[1] - $chunk->[0];
        if ($diff > 1) {
            $from .= tr_chr($chunk->[0]) . "-" . tr_chr($chunk->[1]);
        } elsif ($diff == 1) {
            $from .= tr_chr($chunk->[0]) . tr_chr($chunk->[1]);
        } else {
            $from .= tr_chr($chunk->[0]);
        }
    }
    for my $chunk (@to) {
        $diff = $chunk->[1] - $chunk->[0];
        if ($diff > 1) {
            $to .= tr_chr($chunk->[0]) . "-" . tr_chr($chunk->[1]);
        } elsif ($diff == 1) {
            $to .= tr_chr($chunk->[0]) . tr_chr($chunk->[1]);
        } else {
            $to .= tr_chr($chunk->[0]);
        }
    }
    #$final = sprintf("%04x", $final) if defined $final;
    #$none = sprintf("%04x", $none) if defined $none;
    #$extra = sprintf("%04x", $extra) if defined $extra;
    #print STDERR "final: $final\n none: $none\nextra: $extra\n";
    #print STDERR $swash{'LIST'}->PV;
    return (escape_str($from), escape_str($to));
}

sub pp_trans {
    my $self = shift;
    my($op, $cx) = @_;
    my($from, $to);
    my $class = class($op);
    my $priv_flags = $op->private;
    if ($class eq "PVOP") {
        ($from, $to) = tr_decode_byte($op->pv, $priv_flags);
    } elsif ($class eq "PADOP") {
        ($from, $to)
          = tr_decode_utf8($self->padval($op->padix)->RV, $priv_flags);
    } else { # class($op) eq "SVOP"
        ($from, $to) = tr_decode_utf8($op->sv->RV, $priv_flags);
    }
    my $flags = "";
    $flags .= "c" if $priv_flags & OPpTRANS_COMPLEMENT;
    $flags .= "d" if $priv_flags & OPpTRANS_DELETE;
    $to = "" if $from eq $to and $flags eq "";
    $flags .= "s" if $priv_flags & OPpTRANS_SQUASH;
    return "tr" . double_delim($from, $to) . $flags;
}

sub pp_transr { &pp_trans . 'r' }

sub re_dq_disambiguate {
    my ($first, $last) = @_;
    # Disambiguate "${foo}bar", "${foo}{bar}", "${foo}[1]"
    ($last =~ /^[A-Z\\\^\[\]_?]/ &&
        $first =~ s/([\$@])\^$/${1}{^}/)  # "${^}W" etc
        || ($last =~ /^[{\[\w_]/ &&
            $first =~ s/([\$@])([A-Za-z_]\w*)$/${1}{$2}/);
    return $first . $last;
}

# Like dq(), but different
sub re_dq {
    my $self = shift;
    my ($op, $extended) = @_;

    my $type = $op->name;
    if ($type eq "const") {
        return '$[' if $op->private & OPpCONST_ARYBASE;
        my $unbacked = re_unback($self->const_sv($op)->as_string);
        return re_uninterp_extended(escape_extended_re($unbacked))
            if $extended;
        return re_uninterp(escape_str($unbacked));
    } elsif ($type eq "concat") {
        my $first = $self->re_dq($op->first, $extended);
        my $last  = $self->re_dq($op->last,  $extended);
        return re_dq_disambiguate($first, $last);
    } elsif ($type eq "uc") {
        return '\U' . $self->re_dq($op->first->sibling, $extended) . '\E';
    } elsif ($type eq "lc") {
        return '\L' . $self->re_dq($op->first->sibling, $extended) . '\E';
    } elsif ($type eq "ucfirst") {
        return '\u' . $self->re_dq($op->first->sibling, $extended);
    } elsif ($type eq "lcfirst") {
        return '\l' . $self->re_dq($op->first->sibling, $extended);
    } elsif ($type eq "quotemeta") {
        return '\Q' . $self->re_dq($op->first->sibling, $extended) . '\E';
    } elsif ($type eq "join") {
        return $self->deparse($op->last, 26); # was join($", @ary)
    } else {
        return $self->deparse($op, 26);
    }
}

sub pure_string {
    my ($self, $op) = @_;
    return 0 if null $op;
    my $type = $op->name;

    if ($type eq 'const') {
        return 1;
    }
    elsif ($type =~ /^[ul]c(first)?$/ || $type eq 'quotemeta') {
        return $self->pure_string($op->first->sibling);
    }
    elsif ($type eq 'join') {
        my $join_op = $op->first->sibling;  # Skip pushmark
        return 0 unless $join_op->name eq 'null' && $join_op->targ eq OP_RV2SV;

        my $gvop = $join_op->first;
        return 0 unless $gvop->name eq 'gvsv';
        return 0 unless '"' eq $self->gv_name($self->gv_or_padgv($gvop));

        return 0 unless ${$join_op->sibling} eq ${$op->last};
        return 0 unless $op->last->name =~ /^(?:[ah]slice|(?:rv2|pad)av)$/;
    }
    elsif ($type eq 'concat') {
        return $self->pure_string($op->first)
            && $self->pure_string($op->last);
    }
    elsif (is_scalar($op) || $type =~ /^[ah]elem$/) {
        return 1;
    }
    elsif ($type eq "null" and $op->can('first') and not null $op->first and
           $op->first->name eq "null" and $op->first->can('first')
           and not null $op->first->first and
           $op->first->first->name eq "aelemfast") {
        return 1;
    }
    else {
        return 0;
    }

    return 1;
}

sub regcomp {
    my $self = shift;
    my($op, $cx, $extended) = @_;
    my $kid = $op->first;
    $kid = $kid->first if $kid->name eq "regcmaybe";
    $kid = $kid->first if $kid->name eq "regcreset";
    if ($kid->name eq "null" and !null($kid->first)
        and $kid->first->name eq 'pushmark')
    {
        my $str = '';
        $kid = $kid->first->sibling;
        while (!null($kid)) {
            my $first = $str;
            my $last = $self->re_dq($kid, $extended);
            $str = re_dq_disambiguate($first, $last);
            $kid = $kid->sibling;
        }
        return $str, 1;
    }

    return ($self->re_dq($kid, $extended), 1) if $self->pure_string($kid);
    return ($self->deparse($kid, $cx), 0);
}

sub pp_regcomp {
    my ($self, $op, $cx) = @_;
    return (($self->regcomp($op, $cx, 0))[0]);
}

# osmic acid -- see osmium tetroxide

my %matchwords;
map($matchwords{join "", sort split //, $_} = $_, 'cig', 'cog', 'cos', 'cogs',
    'cox', 'go', 'is', 'ism', 'iso', 'mig', 'mix', 'osmic', 'ox', 'sic',
    'sig', 'six', 'smog', 'so', 'soc', 'sog', 'xi');

sub matchop {
    my $self = shift;
    my($op, $cx, $name, $delim) = @_;
    my $kid = $op->first;
    my ($binop, $var, $re) = ("", "", "");
    if ($op->flags & OPf_STACKED) {
        $binop = 1;
        $var = $self->deparse($kid, 20);
        $kid = $kid->sibling;
    }
    my $quote = 1;
    my $extended = ($op->pmflags & PMf_EXTENDED);
    my $rhs_bound_to_defsv;
    if (null $kid) {
        my $unbacked = re_unback($op->precomp);
        if ($extended) {
            $re = re_uninterp_extended(escape_extended_re($unbacked));
        } else {
            $re = re_uninterp(escape_str(re_unback($op->precomp)));
        }
    } elsif ($kid->name ne 'regcomp') {
        carp("found ".$kid->name." where regcomp expected");
    } else {
        ($re, $quote) = $self->regcomp($kid, 21, $extended);
        $rhs_bound_to_defsv = 1 if $kid->first->first->flags & OPf_SPECIAL;
    }
    my $flags = "";
    $flags .= "c" if $op->pmflags & PMf_CONTINUE;
    $flags .= "g" if $op->pmflags & PMf_GLOBAL;
    $flags .= "i" if $op->pmflags & PMf_FOLD;
    $flags .= "m" if $op->pmflags & PMf_MULTILINE;
    $flags .= "o" if $op->pmflags & PMf_KEEP;
    $flags .= "s" if $op->pmflags & PMf_SINGLELINE;
    $flags .= "x" if $op->pmflags & PMf_EXTENDED;
    $flags = $matchwords{$flags} if $matchwords{$flags};
    if ($op->pmflags & PMf_ONCE) { # only one kind of delimiter works here
        $re =~ s/\?/\\?/g;
        $re = "?$re?";
    } elsif ($quote) {
        $re = single_delim($name, $delim, $re);
    }
    $re = $re . $flags if $quote;
    if ($binop) {
        return
         $self->maybe_parens(
          $rhs_bound_to_defsv
           ? "$var =~ (\$_ =~ $re)"
           : "$var =~ $re",
          $cx, 20
         );
    } else {
        return $re;
    }
}

sub pp_match { matchop(@_, "m", "/") }
sub pp_pushre { matchop(@_, "m", "/") }
sub pp_qr { matchop(@_, "qr", "") }

sub pp_split {
    my $self = shift;
    my($op, $cx) = @_;
    my($kid, @exprs, $ary, $expr);
    $kid = $op->first;

    # For our kid (an OP_PUSHRE), pmreplroot is never actually the
    # root of a replacement; it's either empty, or abused to point to
    # the GV for an array we split into (an optimization to save
    # assignment overhead). Depending on whether we're using ithreads,
    # this OP* holds either a GV* or a PADOFFSET. Luckily, B.xs