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Time | Avg. |
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| 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"; # "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 | | | | |
| 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 | 0.00063 | 0.00063 | BEGIN { require 5.005; } |
| 82 | | | | |
| 83 | 1 | 1.0e-6 | 1.0e-6 | require Exporter; |
| 84 | 1 | 7.0e-6 | 7.0e-6 | @ISA = qw(Exporter); |
| 85 | 1 | 2.0e-6 | 2.0e-6 | @EXPORT = qw(gensym ungensym qualify qualify_to_ref); |
| 86 | 1 | 1.0e-6 | 1.0e-6 | @EXPORT_OK = qw(delete_package geniosym); |
| 87 | | | | |
| 88 | 1 | 1.0e-6 | 1.0e-6 | $VERSION = '1.06'; |
| 89 | | | | |
| 90 | 1 | 1.0e-6 | 1.0e-6 | my $genpkg = "Symbol::"; |
| 91 | 1 | 1.0e-6 | 1.0e-6 | my $genseq = 0; |
| 92 | | | | |
| 93 | 1 | 1.3e-5 | 1.3e-5 | my %global = map {$_ => 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 | | | | sub gensym () { |
| 101 | | | | 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 ($) {} |
| 115 | | | | |
| 116 | | | | sub qualify ($;$) { |
| 117 | | | | my ($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 | 1.1e-5 | 1.1e-5 | 1; |