diff options
Diffstat (limited to 'lib/Exporter.pm')
| -rw-r--r-- | lib/Exporter.pm | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/lib/Exporter.pm b/lib/Exporter.pm index ca1ff3547c..0a7abc5286 100644 --- a/lib/Exporter.pm +++ b/lib/Exporter.pm @@ -36,6 +36,16 @@ Application says: You can set C<$Exporter::Verbose=1;> to see how the specifications are being processed and what is actually being imported 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 +be used to validate that the version of the module being used is +greater than or equal to the required version. + +The Exporter module supplies a default require_version method which +checks the value of $VERSION in the exporting module. + =cut require 5.001; @@ -111,7 +121,15 @@ sub export { foreach $sym (@imports) { if (!$exports{$sym}) { - if ($sym !~ s/^&// || !$exports{$sym}) { + if ($sym =~ m/^\d/) { + $pkg->require_version($sym); + # If the version number was the only thing specified + # then we should act as if nothing was specified: + if (@imports == 1) { + @imports = @exports; + last; + } + } elsif ($sym !~ s/^&// || !$exports{$sym}) { warn qq["$sym" is not exported by the $pkg module ], "at $callfile line $callline\n"; $oops++; @@ -152,4 +170,13 @@ sub export_tags { map {$tags{$_} ? @{$tags{$_}} : $_} @_ ? @_ : keys %tags); } +sub require_version { + my($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; + $version; +} + 1; |