Add version check option

diff --git a/lib/Exporter.pm b/lib/Exporter.pm
index 343b9fb..e374414 100644 (file)
--- a/lib/Exporter.pm
+++ b/lib/Exporter.pm
@@ -91,6 +91,12 @@ 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];
                    $oops++;
@@ -176,9 +182,13 @@ sub export_fail {
 sub require_version {
     my($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)";
+       Carp::croak("$pkg $wanted required--this is only version $version$file")
+    }
     $version;
 }