Re: A useful use of goto

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Re^2: A useful use of goto by Corion (Patriarch) on Apr 12, 2010 at 09:18 UTC
I thought so too, but at least this sample program fails for me: #!perl -w use strict; use Data::Dumper; $Data::Dumper::Sortkeys = 1; my %handler = ( hello => sub() { print "hello world\n" }, ); my ($ok,$err); my @handlers = keys %handler; my $cfg_str = 'test(); hello();'; { no strict 'refs'; # We don't want to introduce another scope, as that will # negate the effect of the local: warn Dumper \%{main::}; # A first my own declaration local {test} = sub { print "This is a test\n"; }; local {$_} = $handler{ $_ } for keys %handler; warn Dumper \%{main::}; print '$handler{hello} ', $handler{ hello },"\n"; print '::{hello} [',::{ hello } \|\| '<none>',"]\n"; $ok = eval $cfg_str; $err = $@; } warn $err if $err; __END__ Name "main::test" used only once: possible typo at tmp.pl line 22. $VAR1 = { ' => {':'}, '☼' => {'::☼'}, '↕' => {'::↕'}, '↨ARNING_BITS' => {'::↨ARNING_BITS'}, '↑' => {'::↑'}, '!' => {'::!'}, '"' => {'::"'}, '$' => {'::$'}, '+' => {'::+'}, '-' => {'::-'}, '/' => {'::/'}, '0' => {'::0'}, '1' => {'::1'}, '<none>::' => {'::<none>::'}, '@' => {'::@'}, 'ARGV' => ::ARGV, 'ActivePerl::' => {'::ActivePerl::'}, 'B::' => {'::B::'}, 'BEGIN' => ::BEGIN, 'CORE::' => {'::CORE::'}, 'Carp::' => {'::Carp::'}, 'Config::' => {'::Config::'}, 'DATA' => ::DATA, 'DB::' => {'::DB::'}, 'Data::' => {'::Data::'}, 'Dumper' => ::Dumper, 'DynaLoader::' => {'::DynaLoader::'}, 'ENV' => ::ENV, 'Exporter::' => {'::Exporter::'}, 'INC' => ::INC, 'IO::' => {'::IO::'}, 'Internals::' => {'::Internals::'}, 'PerlIO::' => {'::PerlIO::'}, 'Regexp::' => {'::Regexp::'}, 'SIG' => ::SIG, 'STDERR' => ::STDERR, 'STDIN' => ::STDIN, 'STDOUT' => ::STDOUT, 'Scalar::' => {'::Scalar::'}, 'UNIVERSAL::' => {'::UNIVERSAL::'}, 'Win32::' => {'::Win32::'}, 'XSLoader::' => {'::XSLoader::'}, '_' => ::_, '_<..\\activeperl.c' => {'::_<..\\activeperl.c'}, '_<..\\perlio.c' => {'::_<..\\perlio.c'}, '_<..\\universal.c' => {'::_<..\\universal.c'}, '_<..\\xsutils.c' => {'::_<..\\xsutils.c'}, '_<.\\win32.c' => {'::_<.\\win32.c'}, '_<C:/Program Files/Perl/lib/auto/Data/Dumper/Dumper.dll' => + {'::_<C:/Program Files/Perl/lib/auto/Data/Dumper/Dumper.dll' }, '_<Dumper.c' => {'::_<Dumper.c'}, '_<dl_win32.c' => {'::_<dl_win32.c'}, '_<perllib.c' => {'::_<perllib.c'}, '__ANON__' => ::__ANON__, 'attributes::' => {'::attributes::'}, 'bytes::' => {'::bytes::'}, 'main::' => {'::main::'}, 'overload::' => {'::overload::'}, 'stderr' => ::stderr, 'stdin' => ::stdin, 'stdout' => ::stdout, 'strict::' => {'::strict::'}, 'test' => ::test, 'utf8::' => {'::utf8::'}, 'warnings::' => {'::warnings::'} }; $VAR1 = { ' => {':'}, '☼' => {'::☼'}, '↕' => {'::↕'}, '↨ARNING_BITS' => {'::↨ARNING_BITS'}, '↑' => {'::↑'}, '!' => {'::!'}, '"' => {'::"'}, '$' => {'::$'}, '+' => {'::+'}, '-' => {'::-'}, '/' => {'::/'}, '0' => {'::0'}, '1' => {'::1'}, '<none>::' => {'::<none>::'}, '@' => {'::@'}, 'ARGV' => ::ARGV, 'ActivePerl::' => {'::ActivePerl::'}, 'B::' => {'::B::'}, 'BEGIN' => ::BEGIN, 'CORE::' => {'::CORE::'}, 'Carp::' => {'::Carp::'}, 'Config::' => {'::Config::'}, 'DATA' => ::DATA, 'DB::' => {'::DB::'}, 'Data::' => {'::Data::'}, 'Dumper' => ::Dumper, 'DynaLoader::' => {'::DynaLoader::'}, 'ENV' => ::ENV, 'Exporter::' => {'::Exporter::'}, 'INC' => ::INC, 'IO::' => {'::IO::'}, 'Internals::' => {'::Internals::'}, 'PerlIO::' => {'::PerlIO::'}, 'Regexp::' => {'::Regexp::'}, 'SIG' => ::SIG, 'STDERR' => ::STDERR, 'STDIN' => ::STDIN, 'STDOUT' => ::STDOUT, 'Scalar::' => {'::Scalar::'}, 'UNIVERSAL::' => {'::UNIVERSAL::'}, 'Win32::' => {'::Win32::'}, 'XSLoader::' => {'::XSLoader::'}, '_' => ::_, '_<..\\activeperl.c' => {'::_<..\\activeperl.c'}, '_<..\\perlio.c' => {'::_<..\\perlio.c'}, '_<..\\universal.c' => {'::_<..\\universal.c'}, '_<..\\xsutils.c' => {'::_<..\\xsutils.c'}, '_<.\\win32.c' => {'::_<.\\win32.c'}, '_<C:/Program Files/Perl/lib/auto/Data/Dumper/Dumper.dll' => + {'::_<C:/Program Files/Perl/lib/auto/Data/Dumper/Dumper.dll' }, '_<Dumper.c' => {'::_<Dumper.c'}, '_<dl_win32.c' => {'::_<dl_win32.c'}, '_<perllib.c' => {'::_<perllib.c'}, '__ANON__' => ::__ANON__, 'attributes::' => {'::attributes::'}, 'bytes::' => {'::bytes::'}, 'hello' => ::hello, 'main::' => {'::main::'}, 'overload::' => {'::overload::'}, 'sort::' => {'::sort::'}, 'stderr' => ::stderr, 'stdin' => ::stdin, 'stdout' => ::stdout, 'strict::' => {'::strict::'}, 'test' => ::test, 'utf8::' => {'::utf8::'}, 'warnings::' => {'::warnings::'} }; $handler{hello} CODE(0x212e788) ::{hello} [<none>] This is a test Undefined subroutine &main::hello called at (eval 1) line 1. [download] ... and it fails in a most weird way, as `::hello` gets a slot after the loop, but it can't find `hello()` while it can find `test()`.	[reply] [d/l] [select]
Re^3: A useful use of goto by JavaFan (Canon) on Apr 12, 2010 at 10:00 UTC
It seems that while the if modifier doesn't introduce a scope, the for modifier does (probably to localize `$_`). So, my suggestion isn't going to work. `:-(`.	[reply] [d/l]