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Edit File: Showlex.pm
package B::Showlex; our $VERSION = '1.05'; use strict; use B qw(svref_2object comppadlist class); use B::Terse (); use B::Concise (); # # Invoke as # perl -MO=Showlex,foo bar.pl # to see the names of lexical variables used by &foo # or as # perl -MO=Showlex bar.pl # to see the names of file scope lexicals used by bar.pl # # borrowed from B::Concise our $walkHandle = \*STDOUT; sub walk_output { # updates $walkHandle $walkHandle = B::Concise::walk_output(@_); #print "got $walkHandle"; #print $walkHandle "using it"; $walkHandle; } sub shownamearray { my ($name, $av) = @_; my @els = $av->ARRAY; my $count = @els; my $i; print $walkHandle "$name has $count entries\n"; for ($i = 0; $i < $count; $i++) { my $sv = $els[$i]; if (class($sv) ne "SPECIAL") { printf $walkHandle "$i: (0x%lx) %s\n", $$sv, $sv->PVX // "undef" || "const"; } else { printf $walkHandle "$i: %s\n", $sv->terse; #printf $walkHandle "$i: %s\n", B::Concise::concise_sv($sv); } } } sub showvaluearray { my ($name, $av) = @_; my @els = $av->ARRAY; my $count = @els; my $i; print $walkHandle "$name has $count entries\n"; for ($i = 0; $i < $count; $i++) { printf $walkHandle "$i: %s\n", $els[$i]->terse; #print $walkHandle "$i: %s\n", B::Concise::concise_sv($els[$i]); } } sub showlex { my ($objname, $namesav, $valsav) = @_; shownamearray("Pad of lexical names for $objname", $namesav); showvaluearray("Pad of lexical values for $objname", $valsav); } my ($newlex, $nosp1); # rendering state vars sub padname_terse { my $name = shift; return $name->terse if class($name) eq 'SPECIAL'; my $str = $name->PVX; return sprintf "(0x%lx) %s", $$name, length $str ? qq'"$str"' : defined $str ? "const" : 'undef'; } sub newlex { # drop-in for showlex my ($objname, $names, $vals) = @_; my @names = $names->ARRAY; my @vals = $vals->ARRAY; my $count = @names; print $walkHandle "$objname Pad has $count entries\n"; printf $walkHandle "0: %s\n", padname_terse($names[0]) unless $nosp1; for (my $i = 1; $i < $count; $i++) { printf $walkHandle "$i: %s = %s\n", padname_terse($names[$i]), $vals[$i]->terse, unless $nosp1 and class($names[$i]) eq 'SPECIAL' || !$names[$i]->LEN; } } sub showlex_obj { my ($objname, $obj) = @_; $objname =~ s/^&main::/&/; showlex($objname, svref_2object($obj)->PADLIST->ARRAY) if !$newlex; newlex ($objname, svref_2object($obj)->PADLIST->ARRAY) if $newlex; } sub showlex_main { showlex("comppadlist", comppadlist->ARRAY) if !$newlex; newlex ("main", comppadlist->ARRAY) if $newlex; } sub compile { my @options = grep(/^-/, @_); my @args = grep(!/^-/, @_); for my $o (@options) { $newlex = 1 if $o eq "-newlex"; $nosp1 = 1 if $o eq "-nosp"; } return \&showlex_main unless @args; return sub { my $objref; foreach my $objname (@args) { next unless $objname; # skip nulls w/o carping if (ref $objname) { print $walkHandle "B::Showlex::compile($objname)\n"; $objref = $objname; } else { $objname = "main::$objname" unless $objname =~ /::/; print $walkHandle "$objname:\n"; no strict 'refs'; die "err: unknown function ($objname)\n" unless *{$objname}{CODE}; $objref = \&$objname; } showlex_obj($objname, $objref); } } } 1; __END__ =head1 NAME B::Showlex - Show lexical variables used in functions or files =head1 SYNOPSIS perl -MO=Showlex[,-OPTIONS][,SUBROUTINE] foo.pl =head1 DESCRIPTION When a comma-separated list of subroutine names is given as options, Showlex prints the lexical variables used in those subroutines. Otherwise, it prints the file-scope lexicals in the file. =head1 EXAMPLES Traditional form: $ perl -MO=Showlex -e 'my ($i,$j,$k)=(1,"foo")' Pad of lexical names for comppadlist has 4 entries 0: (0x8caea4) undef 1: (0x9db0fb0) $i 2: (0x9db0f38) $j 3: (0x9db0f50) $k Pad of lexical values for comppadlist has 5 entries 0: SPECIAL #1 &PL_sv_undef 1: NULL (0x9da4234) 2: NULL (0x9db0f2c) 3: NULL (0x9db0f44) 4: NULL (0x9da4264) -e syntax OK New-style form: $ perl -MO=Showlex,-newlex -e 'my ($i,$j,$k)=(1,"foo")' main Pad has 4 entries 0: (0x8caea4) undef 1: (0xa0c4fb8) "$i" = NULL (0xa0b8234) 2: (0xa0c4f40) "$j" = NULL (0xa0c4f34) 3: (0xa0c4f58) "$k" = NULL (0xa0c4f4c) -e syntax OK New form, no specials, outside O framework: $ perl -MB::Showlex -e \ 'my ($i,$j,$k)=(1,"foo"); B::Showlex::compile(-newlex,-nosp)->()' main Pad has 4 entries 1: (0x998ffb0) "$i" = IV (0x9983234) 1 2: (0x998ff68) "$j" = PV (0x998ff5c) "foo" 3: (0x998ff80) "$k" = NULL (0x998ff74) Note that this example shows the values of the lexicals, whereas the other examples did not (as they're compile-time only). =head2 OPTIONS The C<-newlex> option produces a more readable C<< name => value >> format, and is shown in the second example above. The C<-nosp> option eliminates reporting of SPECIALs, such as C<0: SPECIAL #1 &PL_sv_undef> above. Reporting of SPECIALs can sometimes overwhelm your declared lexicals. =head1 SEE ALSO L<B::Showlex> can also be used outside of the O framework, as in the third example. See L<B::Concise> for a fuller explanation of reasons. =head1 TODO Some of the reported info, such as hex addresses, is not particularly valuable. Other information would be more useful for the typical programmer, such as line-numbers, pad-slot reuses, etc.. Given this, -newlex is not a particularly good flag-name. =head1 AUTHOR Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> =cut