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For ddd2.pl
  Run on Tue May 25 16:52:24 2010
Reported on Tue May 25 16:56:45 2010

File /usr/local/lib/perl5/5.8.8/Symbol.pm
Statements Executed 4620
Statement Execution Time 44.3ms
Subroutines — ordered by exclusive time
Calls P F Exclusive
Time
Inclusive
Time
Subroutine
9222220.4ms20.4msSymbol::::qualifySymbol::qualify
4611119.4ms19.4msSymbol::::gensymSymbol::gensym
0000s0sSymbol::::BEGINSymbol::BEGIN
0000s0sSymbol::::delete_packageSymbol::delete_package
0000s0sSymbol::::geniosymSymbol::geniosym
0000s0sSymbol::::qualify_to_refSymbol::qualify_to_ref
0000s0sSymbol::::ungensymSymbol::ungensym
Call graph for these subroutines as a Graphviz dot language file.
Line State
ments
Time
on line
Calls Time
in subs
Code
1package Symbol;
2
3=head1 NAME
4
5Symbol - manipulate Perl symbols and their names
6
7=head1 SYNOPSIS
8
9 use Symbol;
10
11 $sym = gensym;
12 open($sym, "filename");
13 $_ = <$sym>;
14 # etc.
15
16 ungensym $sym; # no effect
17
18 # replace *FOO{IO} handle but not $FOO, %FOO, etc.
19 *FOO = geniosym;
20
21 print qualify("x"), "\n"; # "Test::x"
22 print qualify("x", "FOO"), "\n" # "FOO::x"
23 print qualify("BAR::x"), "\n"; # "BAR::x"
24 print qualify("BAR::x", "FOO"), "\n"; # "BAR::x"
25 print qualify("STDOUT", "FOO"), "\n"; # "main::STDOUT" (global)
26 print qualify(\*x), "\n"; # returns \*x
27 print qualify(\*x, "FOO"), "\n"; # returns \*x
28
29 use strict refs;
30 print { qualify_to_ref $fh } "foo!\n";
31 $ref = qualify_to_ref $name, $pkg;
32
33 use Symbol qw(delete_package);
34 delete_package('Foo::Bar');
35 print "deleted\n" unless exists $Foo::{'Bar::'};
36
37=head1 DESCRIPTION
38
39C<Symbol::gensym> creates an anonymous glob and returns a reference
40to it. Such a glob reference can be used as a file or directory
41handle.
42
43For backward compatibility with older implementations that didn't
44support anonymous globs, C<Symbol::ungensym> is also provided.
45But it doesn't do anything.
46
47C<Symbol::geniosym> creates an anonymous IO handle. This can be
48assigned into an existing glob without affecting the non-IO portions
49of the glob.
50
51C<Symbol::qualify> turns unqualified symbol names into qualified
52variable names (e.g. "myvar" -E<gt> "MyPackage::myvar"). If it is given a
53second parameter, C<qualify> uses it as the default package;
54otherwise, it uses the package of its caller. Regardless, global
55variable names (e.g. "STDOUT", "ENV", "SIG") are always qualified with
56"main::".
57
58Qualification applies only to symbol names (strings). References are
59left unchanged under the assumption that they are glob references,
60which are qualified by their nature.
61
62C<Symbol::qualify_to_ref> is just like C<Symbol::qualify> except that it
63returns a glob ref rather than a symbol name, so you can use the result
64even if C<use strict 'refs'> is in effect.
65
66C<Symbol::delete_package> wipes out a whole package namespace. Note
67this routine is not exported by default--you may want to import it
68explicitly.
69
70=head1 BUGS
71
72C<Symbol::delete_package> is a bit too powerful. It undefines every symbol that
73lives in the specified package. Since perl, for performance reasons, does not
74perform a symbol table lookup each time a function is called or a global
75variable is accessed, some code that has already been loaded and that makes use
76of symbols in package C<Foo> may stop working after you delete C<Foo>, even if
77you reload the C<Foo> module afterwards.
78
79=cut
80
8111.16msBEGIN { require 5.005; }
82
8316µsrequire Exporter;
84110µs@ISA = qw(Exporter);
8517µs@EXPORT = qw(gensym ungensym qualify qualify_to_ref);
8615µs@EXPORT_OK = qw(delete_package geniosym);
87
8814µs$VERSION = '1.06';
89
90127µsmy $genpkg = "Symbol::";
9115µsmy $genseq = 0;
92
93121µsmy %global = map {$_ => 1} qw(ARGV ARGVOUT ENV INC SIG STDERR STDIN STDOUT);
94
95#
96# Note that we never _copy_ the glob; we just make a ref to it.
97# If we did copy it, then SVf_FAKE would be set on the copy, and
98# glob-specific behaviors (e.g. C<*$ref = \&func>) wouldn't work.
99#
100
# spent 19.4ms within Symbol::gensym which was called 461 times, avg 42µs/call: # 461 times (19.4ms+0s) by IO::Handle::new at line 308 of IO/Handle.pm, avg 42µs/call
sub gensym () {
101184421.0ms my $name = "GEN" . $genseq++;
102 my $ref = \*{$genpkg . $name};
103 delete $$genpkg{$name};
104 $ref;
105}
106
107sub geniosym () {
108 my $sym = gensym();
109 # force the IO slot to be filled
110 select(select $sym);
111 *$sym{IO};
112}
113
114sub ungensym ($) {}
115
116
# spent 20.4ms within Symbol::qualify which was called 922 times, avg 22µs/call: # 461 times (10.8ms+0s) by IO::Handle::autoflush at line 467 of IO/Handle.pm, avg 23µs/call # 461 times (9.57ms+0s) by SelectSaver::new at line 45 of SelectSaver.pm, avg 21µs/call
sub qualify ($;$) {
117276622.0ms my ($name) = @_;
118 if (!ref($name) && index($name, '::') == -1 && index($name, "'") == -1) {
119 my $pkg;
120 # Global names: special character, "^xyz", or other.
121 if ($name =~ /^(([^a-z])|(\^[a-z_]+))\z/i || $global{$name}) {
122 # RGS 2001-11-05 : translate leading ^X to control-char
123 $name =~ s/^\^([a-z_])/'qq(\c'.$1.')'/eei;
124 $pkg = "main";
125 }
126 else {
127 $pkg = (@_ > 1) ? $_[1] : caller;
128 }
129 $name = $pkg . "::" . $name;
130 }
131 $name;
132}
133
134sub qualify_to_ref ($;$) {
135 return \*{ qualify $_[0], @_ > 1 ? $_[1] : caller };
136}
137
138#
139# of Safe.pm lineage
140#
141sub delete_package ($) {
142 my $pkg = shift;
143
144 # expand to full symbol table name if needed
145
146 unless ($pkg =~ /^main::.*::$/) {
147 $pkg = "main$pkg" if $pkg =~ /^::/;
148 $pkg = "main::$pkg" unless $pkg =~ /^main::/;
149 $pkg .= '::' unless $pkg =~ /::$/;
150 }
151
152 my($stem, $leaf) = $pkg =~ m/(.*::)(\w+::)$/;
153 my $stem_symtab = *{$stem}{HASH};
154 return unless defined $stem_symtab and exists $stem_symtab->{$leaf};
155
156
157 # free all the symbols in the package
158
159 my $leaf_symtab = *{$stem_symtab->{$leaf}}{HASH};
160 foreach my $name (keys %$leaf_symtab) {
161 undef *{$pkg . $name};
162 }
163
164 # delete the symbol table
165
166 %$leaf_symtab = ();
167 delete $stem_symtab->{$leaf};
168}
169
170124µs1;