| 1 | | | | package constant; |
| 2 | 3 | 42µs | 14µs | use 5.005; |
| 3 | 3 | 26µs | 9µs | use strict; |
| 4 | 3 | 31µs | 10µs | use warnings::register; |
| 5 | | | | |
| 6 | 3 | 152µs | 51µs | use vars qw($VERSION %declared); |
| 7 | 1 | 900ns | 900ns | $VERSION = '1.13'; |
| 8 | | | | |
| 9 | | | | #======================================================================= |
| 10 | | | | |
| 11 | | | | # Some names are evil choices. |
| 12 | 1 | 12µs | 12µs | my %keywords = map +($_, 1), qw{ BEGIN INIT CHECK END DESTROY AUTOLOAD }; |
| 13 | 1 | 4µs | 4µs | $keywords{UNITCHECK}++ if $] > 5.009; |
| 14 | | | | |
| 15 | 1 | 8µs | 8µs | my %forced_into_main = map +($_, 1), |
| 16 | | | | qw{ STDIN STDOUT STDERR ARGV ARGVOUT ENV INC SIG }; |
| 17 | | | | |
| 18 | 1 | 8µs | 8µs | my %forbidden = (%keywords, %forced_into_main); |
| 19 | | | | |
| 20 | | | | #======================================================================= |
| 21 | | | | # import() - import symbols into user's namespace |
| 22 | | | | # |
| 23 | | | | # What we actually do is define a function in the caller's namespace |
| 24 | | | | # which returns the value. The function we create will normally |
| 25 | | | | # be inlined as a constant, thereby avoiding further sub calling |
| 26 | | | | # overhead. |
| 27 | | | | #======================================================================= |
| 28 | | | | sub import { |
| 29 | 5106 | 6.99ms | 1µs | my $class = shift; |
| 30 | | | | return unless @_; # Ignore 'use constant;' |
| 31 | | | | my $constants; |
| 32 | | | | my $multiple = ref $_[0]; |
| 33 | | | | my $pkg = caller; |
| 34 | | | | my $symtab; |
| 35 | | | | my $str_end = $] >= 5.006 ? "\\z" : "\\Z"; |
| 36 | | | | |
| 37 | | | | if ($] > 5.009002) { |
| 38 | 3 | 300µs | 100µs | no strict 'refs'; |
| 39 | | | | $symtab = \%{$pkg . '::'}; |
| 40 | | | | }; |
| 41 | | | | |
| 42 | | | | if ( $multiple ) { |
| 43 | | | | if (ref $_[0] ne 'HASH') { |
| 44 | | | | require Carp; |
| 45 | | | | Carp::croak("Invalid reference type '".ref(shift)."' not 'HASH'"); |
| 46 | | | | } |
| 47 | | | | $constants = shift; |
| 48 | | | | } else { |
| 49 | | | | $constants->{+shift} = undef; |
| 50 | | | | } |
| 51 | | | | |
| 52 | | | | foreach my $name ( keys %$constants ) { |
| 53 | | | | unless (defined $name) { |
| 54 | | | | require Carp; |
| 55 | | | | Carp::croak("Can't use undef as constant name"); |
| 56 | | | | } |
| 57 | | | | |
| 58 | | | | # Normal constant name |
| 59 | | | | if ($name =~ /^_?[^\W_0-9]\w*$str_end/ and !$forbidden{$name}) { |
| 60 | | | | # Everything is okay |
| 61 | | | | |
| 62 | | | | # Name forced into main, but we're not in main. Fatal. |
| 63 | | | | } elsif ($forced_into_main{$name} and $pkg ne 'main') { |
| 64 | | | | require Carp; |
| 65 | | | | Carp::croak("Constant name '$name' is forced into main::"); |
| 66 | | | | |
| 67 | | | | # Starts with double underscore. Fatal. |
| 68 | | | | } elsif ($name =~ /^__/) { |
| 69 | | | | require Carp; |
| 70 | | | | Carp::croak("Constant name '$name' begins with '__'"); |
| 71 | | | | |
| 72 | | | | # Maybe the name is tolerable |
| 73 | | | | } elsif ($name =~ /^[A-Za-z_]\w*$str_end/) { |
| 74 | | | | # Then we'll warn only if you've asked for warnings |
| 75 | | | | if (warnings::enabled()) { |
| 76 | | | | if ($keywords{$name}) { |
| 77 | | | | warnings::warn("Constant name '$name' is a Perl keyword"); |
| 78 | | | | } elsif ($forced_into_main{$name}) { |
| 79 | | | | warnings::warn("Constant name '$name' is " . |
| 80 | | | | "forced into package main::"); |
| 81 | | | | } |
| 82 | | | | } |
| 83 | | | | |
| 84 | | | | # Looks like a boolean |
| 85 | | | | # use constant FRED == fred; |
| 86 | | | | } elsif ($name =~ /^[01]?$str_end/) { |
| 87 | | | | require Carp; |
| 88 | | | | if (@_) { |
| 89 | | | | Carp::croak("Constant name '$name' is invalid"); |
| 90 | | | | } else { |
| 91 | | | | Carp::croak("Constant name looks like boolean value"); |
| 92 | | | | } |
| 93 | | | | |
| 94 | | | | } else { |
| 95 | | | | # Must have bad characters |
| 96 | | | | require Carp; |
| 97 | | | | Carp::croak("Constant name '$name' has invalid characters"); |
| 98 | | | | } |
| 99 | | | | |
| 100 | | | | { |
| 101 | 3 | 248µs | 83µs | no strict 'refs'; |
| 102 | | | | my $full_name = "${pkg}::$name"; |
| 103 | | | | $declared{$full_name}++; |
| 104 | | | | if ($multiple || @_ == 1) { |
| 105 | | | | my $scalar = $multiple ? $constants->{$name} : $_[0]; |
| 106 | | | | if ($symtab && !exists $symtab->{$name}) { |
| 107 | | | | # No typeglob yet, so we can use a reference as space- |
| 108 | | | | # efficient proxy for a constant subroutine |
| 109 | | | | # The check in Perl_ck_rvconst knows that inlinable |
| 110 | | | | # constants from cv_const_sv are read only. So we have to: |
| 111 | | | | Internals::SvREADONLY($scalar, 1); |
| 112 | | | | $symtab->{$name} = \$scalar; |
| 113 | | | | mro::method_changed_in($pkg); |
| 114 | | | | } else { |
| 115 | | | | *$full_name = sub () { $scalar }; |
| 116 | | | | } |
| 117 | | | | } elsif (@_) { |
| 118 | | | | my @list = @_; |
| 119 | | | | *$full_name = sub () { @list }; |
| 120 | | | | } else { |
| 121 | | | | *$full_name = sub () { }; |
| 122 | | | | } |
| 123 | | | | } |
| 124 | | | | } |
| 125 | | | | } |
| 126 | | | | |
| 127 | 1 | 11µs | 11µs | 1; |
| 128 | | | | |
| 129 | | | | __END__ |
| 130 | | | | |