Fix type constraints to get $tc->type_parameter correctly

[gitmo/Mouse.git] / lib / Mouse / Meta / TypeConstraint.pm

diff --git a/lib/Mouse/Meta/TypeConstraint.pm b/lib/Mouse/Meta/TypeConstraint.pm
index 6bb7e21..aa4e9fc 100644 (file)
--- a/lib/Mouse/Meta/TypeConstraint.pm
+++ b/lib/Mouse/Meta/TypeConstraint.pm
@@ -1,6 +1,5 @@
 package Mouse::Meta::TypeConstraint;
 use Mouse::Util qw(:meta); # enables strict and warnings
-use Scalar::Util ();
 
 sub new {
     my $class = shift;
@@ -8,28 +7,51 @@ sub new {
 
     $args{name} = '__ANON__' if !defined $args{name};
 
-    if($args{parent}) {
+    my $type_parameter;
+    if(defined $args{parent}) { # subtyping
         %args = (%{$args{parent}}, %args);
+
         # a child type must not inherit 'compiled_type_constraint'
         # and 'hand_optimized_type_constraint' from the parent
-        delete $args{compiled_type_constraint};
-        delete $args{hand_optimized_type_constraint};
+        delete $args{compiled_type_constraint};       # don't inherit it
+        delete $args{hand_optimized_type_constraint}; # don't inherit it
+
+        $type_parameter = $args{type_parameter};
+        if(defined(my $parent_tp = $args{parent}{type_parameter})) {
+            if($parent_tp != $type_parameter) {
+                $type_parameter->is_a_type_of($parent_tp)
+                    or $class->throw_error(
+                        "$type_parameter is not a subtype of $parent_tp",
+                    );
+            }
+        }
     }
 
     my $check;
 
-    if($check = delete $args{optimized}) {
+    if($check = delete $args{optimized}) { # likely to be builtins
         $args{hand_optimized_type_constraint} = $check;
         $args{compiled_type_constraint}       = $check;
     }
-    elsif(my $param = $args{type_parameter}) {
+    elsif(defined $type_parameter) { # parameterizing
         my $generator = $args{constraint_generator}
-            || $class->throw_error("The $args{name} constraint cannot be used,"
-                . " because $param doesn't subtype from a parameterizable type");
-        # it must be 'constraint'
-        $check = $args{constraint} = $generator->($param);
+            || $class->throw_error(
+                  "The $args{name} constraint cannot be used,"
+                . " because $type_parameter doesn't subtype"
+                . " from a parameterizable type");
+
+        my $parameterized_check = $generator->($type_parameter);
+        if(defined(my $my_check = $args{constraint})) {
+            $check = sub {
+                return $parameterized_check->($_) && $my_check->($_);
+            };
+        }
+        else {
+            $check = $parameterized_check;
+        }
+        $args{constraint} = $check;
     }
-    else {
+    else { # common cases
         $check = $args{constraint};
     }
 
@@ -72,6 +94,11 @@ sub compile_type_constraint;
 sub _add_type_coercions { # ($self, @pairs)
     my $self = shift;
 
+    if(exists $self->{type_constraints}){ # union type
+        $self->throw_error(
+            "Cannot add additional type coercions to Union types '$self'");
+    }
+
     my $coercions = ($self->{coercion_map} ||= []);
     my %has       = map{ $_->[0] => undef } @{$coercions};
 
@@ -90,14 +117,7 @@ sub _add_type_coercions { # ($self, @pairs)
         push @{$coercions}, [ $type => $action ];
     }
 
-    # compile
-    if(exists $self->{type_constraints}){ # union type
-        $self->throw_error(
-            "Cannot add additional type coercions to Union types");
-    }
-    else{
-        $self->_compile_type_coercion();
-    }
+    $self->_compile_type_coercion();
     return;
 }
 
@@ -144,14 +164,10 @@ sub _compile_union_type_coercion {
 
 sub coerce {
     my $self = shift;
-
-    my $coercion = $self->_compiled_type_coercion;
-    if(!$coercion){
-        $self->throw_error("Cannot coerce without a type coercion");
-    }
-
     return $_[0] if $self->check(@_);
 
+    my $coercion = $self->{_compiled_type_coercion}
+        or $self->throw_error("Cannot coerce without a type coercion");
     return  $coercion->(@_);
 }
 
@@ -172,7 +188,7 @@ sub get_message {
     }
 }
 
-sub is_a_type_of{
+sub is_a_type_of {
     my($self, $other) = @_;
 
     # ->is_a_type_of('__ANON__') is always false
@@ -196,7 +212,7 @@ sub is_a_type_of{
 }
 
 # See also Moose::Meta::TypeConstraint::Parameterizable
-sub parameterize{
+sub parameterize {
     my($self, $param, $name) = @_;
 
     if(!ref $param){
@@ -222,7 +238,7 @@ sub assert_valid {
 }
 
 sub _as_string { $_[0]->name                  } # overload ""
-sub _identity  { Scalar::Util::refaddr($_[0]) } # overload 0+
+sub _identity;                                  # overload 0+
 
 sub _unite { # overload infix:<|>
     my($lhs, $rhs) = @_;
@@ -241,7 +257,7 @@ Mouse::Meta::TypeConstraint - The Mouse Type Constraint metaclass
 
 =head1 VERSION
 
-This document describes Mouse version 0.74
+This document describes Mouse version 0.81
 
 =head1 DESCRIPTION
 
@@ -266,7 +282,7 @@ constraints
 
 =item C<< $constraint->message >>
 
-=item C<< $constraint->is_a_subtype_of($name or $object) >>
+=item C<< $constraint->is_a_type_of($name or $object) >>
 
 =item C<< $constraint->coerce($value) >>