92 lines
2.0 KiB
Perl
92 lines
2.0 KiB
Perl
package Symbol;
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BEGIN { require 5.005; }
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require Exporter;
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@ISA = qw(Exporter);
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@EXPORT = qw(gensym ungensym qualify qualify_to_ref);
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@EXPORT_OK = qw(delete_package geniosym);
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$VERSION = '1.08';
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my $genpkg = "Symbol::";
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my $genseq = 0;
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my %global = map {$_ => 1} qw(ARGV ARGVOUT ENV INC SIG STDERR STDIN STDOUT);
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#
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# Note that we never _copy_ the glob; we just make a ref to it.
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# If we did copy it, then SVf_FAKE would be set on the copy, and
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# glob-specific behaviors (e.g. C<*$ref = \&func>) wouldn't work.
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#
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sub gensym () {
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my $name = "GEN" . $genseq++;
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my $ref = \*{$genpkg . $name};
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delete $$genpkg{$name};
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$ref;
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}
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sub geniosym () {
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my $sym = gensym();
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# force the IO slot to be filled
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select(select $sym);
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*$sym{IO};
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}
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sub ungensym ($) {}
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sub qualify ($;$) {
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my ($name) = @_;
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if (!ref($name) && index($name, '::') == -1 && index($name, "'") == -1) {
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my $pkg;
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# Global names: special character, "^xyz", or other.
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if ($name =~ /^(([^a-z])|(\^[a-z_]+))\z/i || $global{$name}) {
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# RGS 2001-11-05 : translate leading ^X to control-char
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$name =~ s/^\^([a-z_])/'qq(\c'.$1.')'/eei;
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$pkg = "main";
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}
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else {
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$pkg = (@_ > 1) ? $_[1] : caller;
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}
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$name = $pkg . "::" . $name;
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}
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$name;
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}
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sub qualify_to_ref ($;$) {
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return \*{ qualify $_[0], @_ > 1 ? $_[1] : caller };
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}
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#
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# of Safe.pm lineage
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#
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sub delete_package ($) {
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my $pkg = shift;
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# expand to full symbol table name if needed
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unless ($pkg =~ /^main::.*::$/) {
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$pkg = "main$pkg" if $pkg =~ /^::/;
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$pkg = "main::$pkg" unless $pkg =~ /^main::/;
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$pkg .= '::' unless $pkg =~ /::$/;
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}
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my($stem, $leaf) = $pkg =~ m/(.*::)(\w+::)$/;
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my $stem_symtab = *{$stem}{HASH};
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return unless defined $stem_symtab and exists $stem_symtab->{$leaf};
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# free all the symbols in the package
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my $leaf_symtab = *{$stem_symtab->{$leaf}}{HASH};
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foreach my $name (keys %$leaf_symtab) {
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undef *{$pkg . $name};
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}
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# delete the symbol table
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%$leaf_symtab = ();
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delete $stem_symtab->{$leaf};
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}
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1;
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