Add find_type_for method to Union.

diff --git a/Changes b/Changes
index f63a51b..180b234 100644 (file)
--- a/Changes
+++ b/Changes
@@ -3,6 +3,11 @@ for, noteworthy changes.
 
 0.99 ???
 
+  [NEW FEATURES]
+
+  * New method find_type_for in Moose::Meta::TypeConstraint::Union, for finding
+    which member of the union a given value validates for. (Cory Watson)
+
   [NEW DOCUMENTATION]
 
   * Added Moose::Manual::Support that defines the support, compatiblity, and

diff --git a/lib/Moose/Meta/TypeConstraint/Union.pm b/lib/Moose/Meta/TypeConstraint/Union.pm
index 8cf2ca6..d21ae8b 100644 (file)
--- a/lib/Moose/Meta/TypeConstraint/Union.pm
+++ b/lib/Moose/Meta/TypeConstraint/Union.pm
@@ -7,6 +7,8 @@ use metaclass;
 
 use Moose::Meta::TypeCoercion::Union;
 
+use List::Util qw(first);
+
 our $VERSION   = '0.98';
 $VERSION = eval $VERSION;
 our $AUTHORITY = 'cpan:STEVAN';
@@ -93,6 +95,12 @@ sub validate {
     return ($message . ' in (' . $self->name . ')') ;
 }
 
+sub find_type_for {
+    my ($self, $value) = @_;
+
+    return first { $_->check($value) } @{ $self->type_constraints };
+}
+
 sub is_a_type_of {
     my ($self, $type_name) = @_;
     foreach my $type (@{$self->type_constraints}) {
@@ -197,6 +205,12 @@ messages returned by the member type constraints.
 A type is considered equal if it is also a union type, and the two
 unions have the same member types.
 
+=item B<< $constraint->find_type_for($value) >>
+
+This returns the first member type constraint for which C<check($value)> is
+true, allowing you to determine which of the Union's member type constraints
+a given value matches.
+
 =item B<< $constraint->is_a_type_of($type_name_or_object) >>
 
 This returns true if any of the member type constraints return true

diff --git a/t/040_type_constraints/008_union_types.t b/t/040_type_constraints/008_union_types.t
index cff7248..9dc3ece 100644 (file)
--- a/t/040_type_constraints/008_union_types.t
+++ b/t/040_type_constraints/008_union_types.t
@@ -30,6 +30,10 @@ ok($Str_or_Undef->check('String'), '... (Str | Undef) can accept a String value'
 ok($Str_or_Undef->is_a_type_of($Str), "subtype of Str");
 ok($Str_or_Undef->is_a_type_of($Undef), "subtype of Undef");
 
+cmp_ok($Str_or_Undef->find_type_for('String'), 'eq', 'Str', 'find_type_for Str');
+cmp_ok($Str_or_Undef->find_type_for(undef), 'eq', 'Undef', 'find_type_for Undef');
+ok(!defined($Str_or_Undef->find_type_for(sub { })), 'no find_type_for CodeRef');
+
 ok( !$Str_or_Undef->equals($Str), "not equal to Str" );
 ok( $Str_or_Undef->equals($Str_or_Undef), "equal to self" );
 ok( $Str_or_Undef->equals(Moose::Meta::TypeConstraint::Union->new(type_constraints => [ $Str, $Undef ])), "equal to clone" );