X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/f2c01b15f5d3274b0f6ed66037d846fb617bf496..4fa080dbc664ee90dd374a9a49ac0a4932421bd7:/regen/feature.pl diff --git a/regen/feature.pl b/regen/feature.pl old mode 100644 new mode 100755 index d4e2336..6b95e90 --- a/regen/feature.pl +++ b/regen/feature.pl @@ -5,47 +5,77 @@ # lib/feature.pm # feature.h # -# from information hardcoded into this script. +# from information hardcoded into this script and from two #defines +# in perl.h. # # This script is normally invoked from regen.pl. BEGIN { - require 'regen/regen_lib.pl'; + require './regen/regen_lib.pl'; push @INC, './lib'; } use strict ; -# (feature name) => (internal name, used in %^H) + +########################################################################### +# Hand-editable data + +# (feature name) => (internal name, used in %^H and macro names) my %feature = ( - say => 'feature_say', - state => 'feature_state', - switch => 'feature_switch', - evalbytes => 'feature_evalbytes', - current_sub => 'feature___SUB__', - unicode_eval => 'feature_unieval', - unicode_strings => 'feature_unicode', + say => 'say', + state => 'state', + switch => 'switch', + bitwise => 'bitwise', + evalbytes => 'evalbytes', + array_base => 'arybase', + current_sub => '__SUB__', + refaliasing => 'refaliasing', + postderef_qq => 'postderef_qq', + unicode_eval => 'unieval', + declared_refs => 'myref', + unicode_strings => 'unicode', + fc => 'fc', + signatures => 'signatures', ); -# These work backwards--the presence of the hint elem disables the feature: -my %default_feature = ( - array_base => 'feature_no$[', -); +# NOTE: If a feature is ever enabled in a non-contiguous range of Perl +# versions, any code below that uses %BundleRanges will have to +# be changed to account. +# 5.odd implies the next 5.even, but an explicit 5.even can override it. my %feature_bundle = ( - default => [keys %default_feature], + all => [ keys %feature ], + default => [qw(array_base)], "5.9.5" => [qw(say state switch array_base)], "5.10" => [qw(say state switch array_base)], "5.11" => [qw(say state switch unicode_strings array_base)], - "5.12" => [qw(say state switch unicode_strings array_base)], "5.13" => [qw(say state switch unicode_strings array_base)], - "5.14" => [qw(say state switch unicode_strings array_base)], "5.15" => [qw(say state switch unicode_strings unicode_eval - evalbytes current_sub)], - "5.16" => [qw(say state switch unicode_strings unicode_eval - evalbytes current_sub)], + evalbytes current_sub fc)], + "5.17" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc)], + "5.19" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc)], + "5.21" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc)], + "5.23" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc postderef_qq)], + "5.25" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc postderef_qq)], + "5.27" => [qw(say state switch unicode_strings unicode_eval + evalbytes current_sub fc postderef_qq)], ); +my @noops = qw( postderef lexical_subs ); + + ########################################################################### +# More data generated from the above + +for (keys %feature_bundle) { + next unless /^5\.(\d*[13579])\z/; + $feature_bundle{"5.".($1+1)} ||= $feature_bundle{$_}; +} my %UniqueBundles; # "say state switch" => 5.10 my %Aliases; # 5.12 => 5.11 @@ -58,15 +88,69 @@ for( sort keys %feature_bundle ) { $UniqueBundles{$value} = $_; } } + # start end +my %BundleRanges; # say => ['5.10', '5.15'] # unique bundles for values +for my $bund ( + sort { $a eq 'default' ? -1 : $b eq 'default' ? 1 : $a cmp $b } + values %UniqueBundles +) { + next if $bund =~ /[^\d.]/ and $bund ne 'default'; + for (@{$feature_bundle{$bund}}) { + if (@{$BundleRanges{$_} ||= []} == 2) { + $BundleRanges{$_}[1] = $bund + } + else { + push @{$BundleRanges{$_}}, $bund; + } + } +} -########################################################################### +my $HintShift; +my $HintMask; +my $Uni8Bit; + +open "perl.h", "<", "perl.h" or die "$0 cannot open perl.h: $!"; +while (readline "perl.h") { + next unless /#\s*define\s+(HINT_FEATURE_MASK|HINT_UNI_8_BIT)/; + my $is_u8b = $1 =~ 8; + /(0x[A-Fa-f0-9]+)/ or die "No hex number in:\n\n$_\n "; + if ($is_u8b) { + $Uni8Bit = $1; + } + else { + my $hex = $HintMask = $1; + my $bits = sprintf "%b", oct $1; + $bits =~ /^0*1+(0*)\z/ + or die "Non-contiguous bits in $bits (binary for $hex):\n\n$_\n "; + $HintShift = length $1; + my $bits_needed = + length sprintf "%b", scalar keys %UniqueBundles; + $bits =~ /1{$bits_needed}/ + or die "Not enough bits (need $bits_needed)" + . " in $bits (binary for $hex):\n\n$_\n "; + } + if ($Uni8Bit && $HintMask) { last } +} +die "No HINT_FEATURE_MASK defined in perl.h" unless $HintMask; +die "No HINT_UNI_8_BIT defined in perl.h" unless $Uni8Bit; + +close "perl.h"; + +my @HintedBundles = + ('default', grep !/[^\d.]/, sort values %UniqueBundles); +########################################################################### +# Open files to be generated + my ($pm, $h) = map { open_new($_, '>', { by => 'regen/feature.pl' }); } 'lib/feature.pm', 'feature.h'; +########################################################################### +# Generate lib/feature.pm + while () { last if /^FEATURES$/ ; print $pm $_ ; @@ -82,115 +166,213 @@ sub longest { $long; } -print $pm "my %feature = (\n"; +print $pm "our %feature = (\n"; my $width = length longest keys %feature; -for(sort { length $a <=> length $b } keys %feature) { - print $pm " $_" . " "x($width-length) . " => '$feature{$_}',\n"; -} -print $pm ");\n\n"; - -print $pm "my %default_feature = (\n"; -$width = length longest keys %default_feature; -for(sort { length $a <=> length $b } keys %default_feature) { +for(sort { length $a <=> length $b || $a cmp $b } keys %feature) { print $pm " $_" . " "x($width-length) - . " => '$default_feature{$_}',\n"; + . " => 'feature_$feature{$_}',\n"; } print $pm ");\n\n"; print $pm "our %feature_bundle = (\n"; -my $prevkey; -my $prev; -my @same; -$width = length longest keys %feature_bundle; -for( sort keys %feature_bundle ) { - my $value = join(' ', sort @{$feature_bundle{$_}}); - if (/^5\.\d\d\z/ && $prevkey - && substr($_,-2) - substr($prevkey,-2) == 1 && $value eq $prev) { - push @same, $_; - $prevkey = $_; - next; - } - if(/^5\.\d\d\z/) { - $prev = $value; - $prevkey = $_; - } - print $pm qq' "$_"' . " "x($width-length) . qq' => [qw($value)],\n'; +$width = length longest values %UniqueBundles; +for( sort { $UniqueBundles{$a} cmp $UniqueBundles{$b} } + keys %UniqueBundles ) { + my $bund = $UniqueBundles{$_}; + print $pm qq' "$bund"' . " "x($width-length $bund) + . qq' => [qw($_)],\n'; } print $pm ");\n\n"; -print $pm " -# Each of these is the same as the previous bundle -for (", join(',',map /\.(.*)/, @same), ') { - $feature_bundle{"5.$_"} = $feature_bundle{"5.".($_-1)} -}'; +for (sort keys %Aliases) { + print $pm + qq'\$feature_bundle{"$_"} = \$feature_bundle{"$Aliases{$_}"};\n'; +}; + +print $pm "my \%noops = (\n"; +print $pm " $_ => 1,\n", for @noops; +print $pm ");\n"; + +print $pm <) { + last if /^PODTURES$/ ; + print $pm $_ ; +} + +select +(select($pm), $~ = 'PODTURES')[0]; +format PODTURES = + ^<<<<<<<< ^<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<~~ +$::bundle, $::feature +. + +for ('default', sort grep /\.\d[02468]/, keys %feature_bundle) { + $::bundle = ":$_"; + $::feature = join ' ', @{$feature_bundle{$_}}; + write $pm; + print $pm "\n"; +} + +while () { print $pm $_ ; } read_only_bottom_close_and_rename($pm); -my $HintShift; -open "perl.h", "perl.h" or die "$0 cannot open perl.h: $!"; -perlh: { - while (readline "perl.h") { - next unless /#define\s+HINT_FEATURE_MASK/; - /(0x[A-Fa-f0-9]+)/ or die "No hex number in:\n\n$_\n "; - my $hex = $1; - my $bits = sprintf "%b", oct $1; - $bits =~ /^0*1+(0*)\z/ - or die "Non-contiguous bits in $bits (binary for $hex):\n\n$_\n "; - $HintShift = length $1; - my $bits_needed = - length sprintf "%b", scalar keys(%feature_bundle) - @same; - $bits =~ /1{$bits_needed}/ - or die "Not enough bits (need $bits_needed)" - . " in $bits (binary for $hex):\n\n$_\n"; - last perlh; - } - die "No HINT_FEATURE_MASK defined in perl.h"; -} -close "perl.h"; +########################################################################### +# Generate feature.h -my $first_bit = sprintf "0x%08x", 1 << $HintShift; print $h <> HINT_FEATURE_SHIFT) + +#define CURRENT_HINTS \ + (PL_curcop == &PL_compiling ? PL_hints : PL_curcop->cop_hints) +#define CURRENT_FEATURE_BUNDLE \ + ((CURRENT_HINTS & HINT_FEATURE_MASK) >> HINT_FEATURE_SHIFT) + +/* Avoid using ... && Perl_feature_is_enabled(...) as that triggers a bug in + the HP-UX cc on PA-RISC */ +#define FEATURE_IS_ENABLED(name) \ + ((CURRENT_HINTS \ + & HINT_LOCALIZE_HH) \ + ? Perl_feature_is_enabled(aTHX_ STR_WITH_LEN(name)) : FALSE) +/* The longest string we pass in. */ +EOH + +my $longest_internal_feature_name = longest values %feature; +print $h < length $b || $a cmp $b } keys %feature +) { + my($first,$last) = + map { (my $__ = uc) =~ y/.//d; $__ } @{$BundleRanges{$_}}; + my $name = $feature{$_}; + my $NAME = uc $name; + if ($last && $first eq 'DEFAULT') { # '>= DEFAULT' warns + print $h <= FEATURE_BUNDLE_$first && \\ + CURRENT_FEATURE_BUNDLE <= FEATURE_BUNDLE_$last) \\ + || (CURRENT_FEATURE_BUNDLE == FEATURE_BUNDLE_CUSTOM && \\ + FEATURE_IS_ENABLED("$name")) \\ + ) + +EOH3 + } + elsif ($first) { + print $h <> HINT_FEATURE_SHIFT #endif /* PERL_CORE or PERL_EXT */ + +#ifdef PERL_IN_OP_C +PERL_STATIC_INLINE void +S_enable_feature_bundle(pTHX_ SV *ver) +{ + SV *comp_ver = sv_newmortal(); + PL_hints = (PL_hints &~ HINT_FEATURE_MASK) + | ( EOH +for (reverse @HintedBundles[1..$#HintedBundles]) { # skip default + my $numver = $_; + if ($numver eq '5.10') { $numver = '5.009005' } # special case + else { $numver =~ s/\./.0/ } # 5.11 => 5.011 + (my $macrover = $_) =~ y/.//d; + print $h <<" EOK"; + (sv_setnv(comp_ver, $numver), + vcmp(ver, upg_version(comp_ver, FALSE)) >= 0) + ? FEATURE_BUNDLE_$macrover : + EOK +} + +print $h < 2) @@ -226,7 +408,7 @@ pragma.) =head2 Lexical effect Like other pragmas (C, for example), features have a lexical -effect. C will only make the feature "foo" available +effect. C will only make the feature "foo" available from that point to the end of the enclosing block. { @@ -248,7 +430,8 @@ has lexical effect. } say "Yet it is here."; -C with no features specified will turn off all features. +C with no features specified will reset to the default group. To +disable I features (an unusual request!) use C. =head1 AVAILABLE FEATURES @@ -272,78 +455,60 @@ This feature is available starting with Perl 5.10. =head2 The 'switch' feature +B: Because the L is +experimental, Perl will warn when you use this feature, unless you have +explicitly disabled the warning: + + no warnings "experimental::smartmatch"; + C tells the compiler to enable the Perl 6 given/when construct. -See L for details. +See L for details. This feature is available starting with Perl 5.10. =head2 The 'unicode_strings' feature -C tells the compiler to use Unicode semantics +C tells the compiler to use Unicode rules in all string operations executed within its scope (unless they are also within the scope of either C or C). The same applies to all regular expressions compiled within the scope, even if executed outside -it. +it. It does not change the internal representation of strings, but only how +they are interpreted. C tells the compiler to use the traditional -Perl semantics wherein the native character set semantics is used unless it is +Perl rules wherein the native character set rules is used unless it is clear to Perl that Unicode is desired. This can lead to some surprises when the behavior suddenly changes. (See L for details.) For this reason, if you are potentially using Unicode in your program, the C subpragma is B recommended. -This feature is available starting with Perl 5.12, but was not fully -implemented until Perl 5.14. +This feature is available starting with Perl 5.12; was almost fully +implemented in Perl 5.14; and extended in Perl 5.16 to cover C; +was extended further in Perl 5.26 to cover L; and was extended again in Perl 5.28 to +cover L. =head2 The 'unicode_eval' and 'evalbytes' features -Under the C feature, Perl's C function, when passed a -string, will evaluate it as a string of characters, ignoring any -C declarations. C exists to declare the encoding of -the script, which only makes sense for a stream of bytes, not a string of -characters. Source filters are forbidden, as they also really only make -sense on strings of bytes. Any attempt to activate a source filter will -result in an error. - -The C feature enables the C keyword, which evaluates -the argument passed to it as a string of bytes. It dies if the string -contains any characters outside the 8-bit range. Source filters work -within C: they apply to the contents of the string being -evaluated. +Together, these two features are intended to replace the legacy string +C function, which behaves problematically in some instances. They are +available starting with Perl 5.16, and are enabled by default by a +S> or higher declaration. -Together, these two features are intended to replace the historical C -function, which has (at least) two bugs in it, that cannot easily be fixed -without breaking existing programs: +C changes the behavior of plain string C to work more +consistently, especially in the Unicode world. Certain (mis)behaviors +couldn't be changed without breaking some things that had come to rely on +them, so the feature can be enabled and disabled. Details are at +L. -=over - -=item * - -C behaves differently depending on the internal encoding of the -string, sometimes treating its argument as a string of bytes, and sometimes -as a string of characters. - -=item * - -Source filters activated within C leak out into whichever I -scope is currently being compiled. To give an example with the CPAN module -L: - - BEGIN { eval "use Semi::Semicolons; # not filtered here " } - # filtered here! - -C fixes that to work the way one would expect: - - use feature "evalbytes"; - BEGIN { evalbytes "use Semi::Semicolons; # filtered " } - # not filtered - -=back - -These two features are available starting with Perl 5.16. +C is like string C, but operating on a byte stream that is +not UTF-8 encoded. Details are at L. Without a +S> nor a S> (or higher) declaration in +the current scope, you can still access it by instead writing +C. =head2 The 'current_sub' feature @@ -362,6 +527,137 @@ This feature is available under this name starting with Perl 5.16. In previous versions, it was simply on all the time, and this pragma knew nothing about it. +=head2 The 'fc' feature + +C tells the compiler to enable the C function, +which implements Unicode casefolding. + +See L for details. + +This feature is available from Perl 5.16 onwards. + +=head2 The 'lexical_subs' feature + +In Perl versions prior to 5.26, this feature enabled +declaration of subroutines via C, C +and C syntax. See L for details. + +This feature is available from Perl 5.18 onwards. From Perl 5.18 to 5.24, +it was classed as experimental, and Perl emitted a warning for its +usage, except when explicitly disabled: + + no warnings "experimental::lexical_subs"; + +As of Perl 5.26, use of this feature no longer triggers a warning, though +the C warning category still exists (for +compatibility with code that disables it). In addition, this syntax is +not only no longer experimental, but it is enabled for all Perl code, +regardless of what feature declarations are in scope. + +=head2 The 'postderef' and 'postderef_qq' features + +The 'postderef_qq' feature extends the applicability of L so that postfix array +and scalar dereference are available in double-quotish interpolations. For +example, it makes the following two statements equivalent: + + my $s = "[@{ $h->{a} }]"; + my $s = "[$h->{a}->@*]"; + +This feature is available from Perl 5.20 onwards. In Perl 5.20 and 5.22, it +was classed as experimental, and Perl emitted a warning for its +usage, except when explicitly disabled: + + no warnings "experimental::postderef"; + +As of Perl 5.24, use of this feature no longer triggers a warning, though +the C warning category still exists (for +compatibility with code that disables it). + +The 'postderef' feature was used in Perl 5.20 and Perl 5.22 to enable +postfix dereference syntax outside double-quotish interpolations. In those +versions, using it triggered the C warning in the +same way as the 'postderef_qq' feature did. As of Perl 5.24, this syntax is +not only no longer experimental, but it is enabled for all Perl code, +regardless of what feature declarations are in scope. + +=head2 The 'signatures' feature + +B: This feature is still experimental and the implementation may +change in future versions of Perl. For this reason, Perl will +warn when you use the feature, unless you have explicitly disabled the +warning: + + no warnings "experimental::signatures"; + +This enables unpacking of subroutine arguments into lexical variables +by syntax such as + + sub foo ($left, $right) { + return $left + $right; + } + +See L for details. + +This feature is available from Perl 5.20 onwards. + +=head2 The 'refaliasing' feature + +B: This feature is still experimental and the implementation may +change in future versions of Perl. For this reason, Perl will +warn when you use the feature, unless you have explicitly disabled the +warning: + + no warnings "experimental::refaliasing"; + +This enables aliasing via assignment to references: + + \$a = \$b; # $a and $b now point to the same scalar + \@a = \@b; # to the same array + \%a = \%b; + \&a = \&b; + foreach \%hash (@array_of_hash_refs) { + ... + } + +See L for details. + +This feature is available from Perl 5.22 onwards. + +=head2 The 'bitwise' feature + +B: This feature is still experimental and the implementation may +change in future versions of Perl. For this reason, Perl will +warn when you use the feature, unless you have explicitly disabled the +warning: + + no warnings "experimental::bitwise"; + +This makes the four standard bitwise operators (C<& | ^ ~>) treat their +operands consistently as numbers, and introduces four new dotted operators +(C<&. |. ^. ~.>) that treat their operands consistently as strings. The +same applies to the assignment variants (C<&= |= ^= &.= |.= ^.=>). + +See L for details. + +This feature is available from Perl 5.22 onwards. + +=head2 The 'declared_refs' feature + +B: This feature is still experimental and the implementation may +change in future versions of Perl. For this reason, Perl will +warn when you use the feature, unless you have explicitly disabled the +warning: + + no warnings "experimental::declared_refs"; + +This allows a reference to a variable to be declared with C, C, +our C, or localized with C. It is intended mainly for use in +conjunction with the "refaliasing" feature. See L for examples. + +This feature is available from Perl 5.26 onwards. + =head1 FEATURE BUNDLES It's possible to load multiple features together, using @@ -374,17 +670,7 @@ The following feature bundles are available: bundle features included --------- ----------------- - :default array_base - - :5.10 say state switch array_base - - :5.12 say state switch unicode_strings array_base - - :5.14 say state switch unicode_strings array_base - - :5.16 say state switch unicode_strings - unicode_eval evalbytes current_sub - +PODTURES The C<:default> bundle represents the feature set that is enabled before any C or C declaration. @@ -418,7 +704,7 @@ the C construct. That is, will do an implicit - no feature; + no feature ':all'; use feature ':5.10'; and so on. Note how the trailing sub-version @@ -439,45 +725,43 @@ bundle is automatically loaded instead. =cut sub import { - my $class = shift; - if (@_ == 0) { + shift; + + if (!@_) { croak("No features specified"); } - while (@_) { - my $name = shift(@_); - if (substr($name, 0, 1) eq ":") { - my $v = substr($name, 1); - if (!exists $feature_bundle{$v}) { - $v =~ s/^([0-9]+)\.([0-9]+).[0-9]+$/$1.$2/; - if (!exists $feature_bundle{$v}) { - unknown_feature_bundle(substr($name, 1)); - } - } - unshift @_, @{$feature_bundle{$v}}; - next; - } - if (!exists $feature{$name}) { - if (!exists $default_feature{$name}) { - unknown_feature($name); - } - delete $^H{$default_feature{$name}}; next; - } - $^H{$feature{$name}} = 1; - $^H |= $hint_uni8bit if $name eq 'unicode_strings'; - } + + __common(1, @_); } sub unimport { - my $class = shift; + shift; - # A bare C should disable *all* features + # A bare C should reset to the default bundle if (!@_) { - delete @^H{ values(%feature) }; - $^H &= ~ $hint_uni8bit; - @^H{ values(%default_feature) } = (1) x keys %default_feature; - return; + $^H &= ~($hint_uni8bit|$hint_mask); + return; } + __common(0, @_); +} + + +sub __common { + my $import = shift; + my $bundle_number = $^H & $hint_mask; + my $features = $bundle_number != $hint_mask + && $feature_bundle{$hint_bundles[$bundle_number >> $hint_shift]}; + if ($features) { + # Features are enabled implicitly via bundle hints. + # Delete any keys that may be left over from last time. + delete @^H{ values(%feature) }; + $^H |= $hint_mask; + for (@$features) { + $^H{$feature{$_}} = 1; + $^H |= $hint_uni8bit if $_ eq 'unicode_strings'; + } + } while (@_) { my $name = shift; if (substr($name, 0, 1) eq ":") { @@ -491,13 +775,16 @@ sub unimport { unshift @_, @{$feature_bundle{$v}}; next; } - if (!exists($feature{$name})) { - if (!exists $default_feature{$name}) { + if (!exists $feature{$name}) { + if (exists $noops{$name}) { + next; + } unknown_feature($name); - } - $^H{$default_feature{$name}} = 1; next; } - else { + if ($import) { + $^H{$feature{$name}} = 1; + $^H |= $hint_uni8bit if $name eq 'unicode_strings'; + } else { delete $^H{$feature{$name}}; $^H &= ~ $hint_uni8bit if $name eq 'unicode_strings'; }