| File | /usr/local/lib/perl5/5.10.1/Symbol.pm |
| Statements Executed | 30 |
| Statement Execution Time | 592µs |
| Calls | P | F | Exclusive Time |
Inclusive Time |
Subroutine |
|---|---|---|---|---|---|
| 1 | 1 | 1 | 22µs | 22µs | Symbol::BEGIN@81 |
| 2 | 1 | 1 | 22µs | 22µs | Symbol::gensym |
| 4 | 2 | 2 | 14µs | 14µs | Symbol::qualify |
| 0 | 0 | 0 | 0s | 0s | Symbol::delete_package |
| 0 | 0 | 0 | 0s | 0s | Symbol::geniosym |
| 0 | 0 | 0 | 0s | 0s | Symbol::qualify_to_ref |
| 0 | 0 | 0 | 0s | 0s | Symbol::ungensym |
| Line | State ments |
Time on line |
Calls | Time in subs |
Code |
|---|---|---|---|---|---|
| 1 | package Symbol; | ||||
| 2 | |||||
| 3 | =head1 NAME | ||||
| 4 | |||||
| 5 | Symbol - 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"; # "main::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 | |||||
| 39 | C<Symbol::gensym> creates an anonymous glob and returns a reference | ||||
| 40 | to it. Such a glob reference can be used as a file or directory | ||||
| 41 | handle. | ||||
| 42 | |||||
| 43 | For backward compatibility with older implementations that didn't | ||||
| 44 | support anonymous globs, C<Symbol::ungensym> is also provided. | ||||
| 45 | But it doesn't do anything. | ||||
| 46 | |||||
| 47 | C<Symbol::geniosym> creates an anonymous IO handle. This can be | ||||
| 48 | assigned into an existing glob without affecting the non-IO portions | ||||
| 49 | of the glob. | ||||
| 50 | |||||
| 51 | C<Symbol::qualify> turns unqualified symbol names into qualified | ||||
| 52 | variable names (e.g. "myvar" -E<gt> "MyPackage::myvar"). If it is given a | ||||
| 53 | second parameter, C<qualify> uses it as the default package; | ||||
| 54 | otherwise, it uses the package of its caller. Regardless, global | ||||
| 55 | variable names (e.g. "STDOUT", "ENV", "SIG") are always qualified with | ||||
| 56 | "main::". | ||||
| 57 | |||||
| 58 | Qualification applies only to symbol names (strings). References are | ||||
| 59 | left unchanged under the assumption that they are glob references, | ||||
| 60 | which are qualified by their nature. | ||||
| 61 | |||||
| 62 | C<Symbol::qualify_to_ref> is just like C<Symbol::qualify> except that it | ||||
| 63 | returns a glob ref rather than a symbol name, so you can use the result | ||||
| 64 | even if C<use strict 'refs'> is in effect. | ||||
| 65 | |||||
| 66 | C<Symbol::delete_package> wipes out a whole package namespace. Note | ||||
| 67 | this routine is not exported by default--you may want to import it | ||||
| 68 | explicitly. | ||||
| 69 | |||||
| 70 | =head1 BUGS | ||||
| 71 | |||||
| 72 | C<Symbol::delete_package> is a bit too powerful. It undefines every symbol that | ||||
| 73 | lives in the specified package. Since perl, for performance reasons, does not | ||||
| 74 | perform a symbol table lookup each time a function is called or a global | ||||
| 75 | variable is accessed, some code that has already been loaded and that makes use | ||||
| 76 | of symbols in package C<Foo> may stop working after you delete C<Foo>, even if | ||||
| 77 | you reload the C<Foo> module afterwards. | ||||
| 78 | |||||
| 79 | =cut | ||||
| 80 | |||||
| 81 | 1 | 514µs | 1 | 22µs | # spent 22µs within Symbol::BEGIN@81 which was called
# once (22µs+0s) by IO::File::BEGIN@131 at line 81 # spent 22µs making 1 call to Symbol::BEGIN@81 |
| 82 | |||||
| 83 | 1 | 2µs | require Exporter; | ||
| 84 | 1 | 9µs | @ISA = qw(Exporter); | ||
| 85 | 1 | 1µs | @EXPORT = qw(gensym ungensym qualify qualify_to_ref); | ||
| 86 | 1 | 500ns | @EXPORT_OK = qw(delete_package geniosym); | ||
| 87 | |||||
| 88 | 1 | 300ns | $VERSION = '1.07'; | ||
| 89 | |||||
| 90 | 1 | 300ns | my $genpkg = "Symbol::"; | ||
| 91 | 1 | 100ns | my $genseq = 0; | ||
| 92 | |||||
| 93 | 1 | 10µs | my %global = map {$_ => 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 22µs within Symbol::gensym which was called 2 times, avg 11µs/call:
# 2 times (22µs+0s) by IO::Handle::new at line 313 of IO/Handle.pm, avg 11µs/call | ||||
| 101 | 8 | 24µs | my $name = "GEN" . $genseq++; | ||
| 102 | my $ref = \*{$genpkg . $name}; | ||||
| 103 | delete $$genpkg{$name}; | ||||
| 104 | $ref; | ||||
| 105 | } | ||||
| 106 | |||||
| 107 | sub geniosym () { | ||||
| 108 | my $sym = gensym(); | ||||
| 109 | # force the IO slot to be filled | ||||
| 110 | select(select $sym); | ||||
| 111 | *$sym{IO}; | ||||
| 112 | } | ||||
| 113 | |||||
| 114 | sub ungensym ($) {} | ||||
| 115 | |||||
| 116 | # spent 14µs within Symbol::qualify which was called 4 times, avg 3µs/call:
# 2 times (10µs+0s) by IO::Handle::autoflush at line 479 of IO/Handle.pm, avg 5µs/call
# 2 times (4µs+0s) by SelectSaver::new at line 45 of SelectSaver.pm, avg 2µs/call | ||||
| 117 | 12 | 17µs | my ($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 | $name; | ||||
| 132 | } | ||||
| 133 | |||||
| 134 | sub qualify_to_ref ($;$) { | ||||
| 135 | return \*{ qualify $_[0], @_ > 1 ? $_[1] : caller }; | ||||
| 136 | } | ||||
| 137 | |||||
| 138 | # | ||||
| 139 | # of Safe.pm lineage | ||||
| 140 | # | ||||
| 141 | sub delete_package ($) { | ||||
| 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 | |||||
| 170 | 1 | 14µs | 1; |