diff options
Diffstat (limited to 'lib/Exporter.pm')
| -rw-r--r-- | lib/Exporter.pm | 65 |
1 files changed, 48 insertions, 17 deletions
diff --git a/lib/Exporter.pm b/lib/Exporter.pm index 343b9fbd17..66459b8af0 100644 --- a/lib/Exporter.pm +++ b/lib/Exporter.pm @@ -2,21 +2,31 @@ package Exporter; require 5.001; +# +# We go to a lot of trouble not to 'require Carp' at file scope, +# because Carp requires Exporter, and something has to give. +# + $ExportLevel = 0; $Verbose = 0 unless $Verbose; -require Carp; - sub export { # First make import warnings look like they're coming from the "use". local $SIG{__WARN__} = sub { my $text = shift; - $text =~ s/ at \S*Exporter.pm line \d+.*\n//; - local $Carp::CarpLevel = 1; # ignore package calling us too. - Carp::carp($text); + if ($text =~ s/ at \S*Exporter.pm line \d+.*\n//) { + require Carp; + local $Carp::CarpLevel = 1; # ignore package calling us too. + Carp::carp($text); + } + else { + warn $text; + } }; local $SIG{__DIE__} = sub { + require Carp; + local $Carp::CarpLevel = 1; # ignore package calling us too. Carp::croak("$_[0]Illegal null symbol in \@${1}::EXPORT") if $_[0] =~ /^Unable to create sub named "(.*?)::"/; }; @@ -91,13 +101,22 @@ sub export { @imports = @exports; last; } + # We need a way to emulate 'use Foo ()' but still + # allow an easy version check: "use Foo 1.23, ''"; + if (@imports == 2 and !$imports[1]) { + @imports = (); + last; + } } elsif ($sym !~ s/^&// || !$exports{$sym}) { warn qq["$sym" is not exported by the $pkg module]; $oops++; } } } - Carp::croak("Can't continue after import errors") if $oops; + if ($oops) { + require Carp; + Carp::croak("Can't continue after import errors"); + } } else { @imports = @exports; @@ -121,7 +140,10 @@ sub export { warn qq["$sym" is not implemented by the $pkg module ], "on this architecture"; } - Carp::croak("Can't continue after import errors") if @failed; + if (@failed) { + require Carp; + Carp::croak("Can't continue after import errors"); + } } } @@ -139,7 +161,7 @@ sub export { $type eq '@' ? \@{"${pkg}::$sym"} : $type eq '%' ? \%{"${pkg}::$sym"} : $type eq '*' ? *{"${pkg}::$sym"} : - Carp::croak("Can't export symbol: $type$sym"); + do { require Carp; Carp::croak("Can't export symbol: $type$sym") }; } } @@ -159,8 +181,11 @@ sub _push_tags { push(@{"${pkg}::$var"}, map { $export_tags{$_} ? @{$export_tags{$_}} : scalar(++$nontag,$_) } (@$syms) ? @$syms : keys %export_tags); - # This may change to a die one day - Carp::carp("Some names are not tags") if $nontag and $^W; + if ($nontag and $^W) { + # This may change to a die one day + require Carp; + Carp::carp("Some names are not tags"); + } } sub export_tags { _push_tags((caller)[0], "EXPORT", \@_) } @@ -170,15 +195,21 @@ sub export_ok_tags { _push_tags((caller)[0], "EXPORT_OK", \@_) } # Default methods sub export_fail { + my $self = shift; @_; } sub require_version { my($self, $wanted) = @_; my $pkg = ref $self || $self; - my $version = ${"${pkg}::VERSION"} || "(undef)"; - Carp::croak("$pkg $wanted required--this is only version $version") - if $version < $wanted; + my $version = ${"${pkg}::VERSION"}; + if (!$version or $version < $wanted) { + $version ||= "(undef)"; + my $file = $INC{"$pkg.pm"}; + $file &&= " ($file)"; + require Carp; + Carp::croak("$pkg $wanted required--this is only version $version$file") + } $version; } @@ -235,7 +266,7 @@ In other files which wish to use ModuleName: =head1 DESCRIPTION The Exporter module implements a default C<import> method which -many modules choose inherit rather than implement their own. +many modules choose to inherit rather than implement their own. Perl automatically calls the C<import> method when processing a C<use> statement for a module. Modules and C<use> are documented @@ -254,7 +285,7 @@ try to use @EXPORT_OK in preference to @EXPORT and avoid short or common symbol names to reduce the risk of name clashes. Generally anything not exported is still accessible from outside the -module using the ModuleName::item_name (or $blessed_ref->method) +module using the ModuleName::item_name (or $blessed_ref-E<gt>method) syntax. By convention you can use a leading underscore on names to informally indicate that they are 'internal' and not for public use. @@ -318,7 +349,7 @@ into modules. =head2 Module Version Checking The Exporter module will convert an attempt to import a number from a -module into a call to $module_name->require_version($value). This can +module into a call to $module_name-E<gt>require_version($value). This can be used to validate that the version of the module being used is greater than or equal to the required version. @@ -339,7 +370,7 @@ or constants that may not exist on some systems. The names of any symbols that cannot be exported should be listed in the C<@EXPORT_FAIL> array. -If a module attempts to import any of these symbols the Exporter will +If a module attempts to import any of these symbols the Exporter will give the module an opportunity to handle the situation before generating an error. The Exporter will call an export_fail method with a list of the failed symbols: |