From: John Napiorkowski <johnn@John-Napiorkowski-MacBook-Pro.local>
Date: Fri, 25 Jun 2010 14:34:30 +0000 (-0400)
Subject: cleanedup coercion docs
X-Git-Tag: 0.03~2
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=52ed7d4d952fd6eaf67bb394eabe215cd2eaf746;p=gitmo%2FMooseX-Dependent.git

cleanedup coercion docs
---

diff --git a/lib/MooseX/Types/Parameterizable.pm b/lib/MooseX/Types/Parameterizable.pm
index f1db92a..e287889 100644
--- a/lib/MooseX/Types/Parameterizable.pm
+++ b/lib/MooseX/Types/Parameterizable.pm
@@ -262,16 +262,32 @@ is a subtype of the parameterizable "Varchar" and it inherits coercions from
 its parent.  This may be a bit surprising to L<Moose> developers, but I believe
 this is the actual desired behavior.
 
-You can of course add extra coercions to a parameterized type:
+You can of course add new coercions to a subtype of a parameterizable type:
 
-    subtype Max40CharStr,
-      as Varchar[40];
+    subtype MySpecialVarchar,
+      as Varchar;
 
-    coerce Max40CharStr,
+    coerce MySpecialVarchar,
       from ...
 
-In which case this new parameterized type would inherit coercions from it's parent
-parameterizable type (Varchar), as well as the additional coercions you've added.
+In which case this new parameterizable type would NOT inherit coercions from
+it's parent parameterizable type (Varchar).  This is done in keeping with how
+generally speaking L<Moose> type constraints avoid complicated coercion inheritance
+schemes, however I am open to discussion if there are valid use cases.
+
+NOTE: One thing you can't do is add a coercion to an already parameterized type.
+Currently the following would throw a hard error:
+
+    subtype 40CharStr,
+      as Varchar[40];
+
+    coerce 40CharStr, ...  # BANG!
+
+This limitation is enforced since generally we expect coercions on the parent.
+However if good use cases arise we may lift this in the future.
+
+In general we are trying to take a conservative approach that keeps in line with
+how most L<Moose> authors expect type constraints to work.
 
 =head2 Recursion
 
diff --git a/t/05-pod-examples.t b/t/05-pod-examples.t
index e16a7b0..5aa6fc5 100644
--- a/t/05-pod-examples.t
+++ b/t/05-pod-examples.t
@@ -199,95 +199,45 @@ use Test::More;
     ## See t/02-types-parameterizable-extended.t for remaining examples tests
 }
 
+{
+    package Test::MooseX::Types::Parameterizable::Coercions;
 
-done_testing;
-
-
-__END__
-
-use MooseX::Types -declare=>[qw(Set UniqueInt PositiveSet PositiveUniqueInt )];
-
-subtype Set,
-  as class_type("Set::Scalar");
-
-subtype UniqueInt,
-  as Parameterizable[Int, Set],
-  where {
-    my ($int, $set) = @_;
-    !$set->has($int);
-  };
-
-subtype PositiveSet,
-  as Set,
-  where {
-    my ($set) = @_;
-    ! grep { $_ < 0 } $set->members;
-  };
-  
-subtype PositiveUniqueInt,
-  as UniqueInt[PositiveSet];
-
-my $set = Set::Scalar->new(-1,-2,1,2,3);
-my $positive_set = Set::Scalar->new(1,2,3);
-my $negative_set = Set::Scalar->new(-1,-2,-3);
-
-ok Set->check($set),
- 'Is a Set';
-
-ok Set->check($positive_set),
- 'Is a Set';
-
-ok Set->check($negative_set),
- 'Is a Set';
-
-ok !PositiveSet->check($set),
- 'Is Not a Positive Set';
-
-ok PositiveSet->check($positive_set),
- 'Is a Positive Set';
-
-ok !PositiveSet->check($negative_set),
- 'Is Not a Positive Set';
-
-ok UniqueInt([$set])->check(100),
- '100 not in Set';
-
-ok UniqueInt([$positive_set])->check(100),
- '100 not in Set';
-
-ok UniqueInt([$negative_set])->check(100),
- '100 not in Set';
-
-ok UniqueInt([$set])->check(-99),
- '-99 not in Set';
-
-ok UniqueInt([$positive_set])->check(-99),
- '-99 not in Set';
+    use Moose;
+    use MooseX::Types::Parameterizable qw(Parameterizable);
+    use MooseX::Types::Moose qw(HashRef ArrayRef Object Str Int);
+    use MooseX::Types -declare=>[qw(Varchar MySpecialVarchar )];
 
-ok UniqueInt([$negative_set])->check(-99),
-  '-99 not in Set';
 
-ok !UniqueInt([$set])->check(2),
- '2 in Set';
+    subtype Varchar,
+      as Parameterizable[Str, Int],
+      where {
+        my($string, $int) = @_;
+        $int >= length($string) ? 1:0;
+      },
+      message { "'$_' is too long"  };
 
-ok !UniqueInt([$positive_set])->check(2),
- '2 in Set';
 
-ok UniqueInt([$negative_set])->check(2),
-  '2 not in Set';
+    coerce Varchar,
+      from Object,
+      via { "$_"; },  ## stringify the object
+      from ArrayRef,
+      via { join '',@$_ };  ## convert array to string
 
+    subtype MySpecialVarchar,
+      as Varchar;
 
-__END__
+    coerce MySpecialVarchar,
+      from HashRef,
+      via { join '', keys %$_ };
 
-ok UniqueInt([$set])->check(100);  ## Okay, 100 isn't in (1,2,3)
-ok UniqueInt([$set])->check(-99);  ## Okay, -99 isn't in (1,2,3)
-ok !UniqueInt([$set])->check(2);  ## Not OK, 2 is in (1,2,3)
 
-ok PositiveUniqueInt([$set])->check(100);  ## Okay, 100 isn't in (1,2,3)
-ok !PositiveUniqueInt([$set])->check(-99);  ## Not OK, -99 not Positive Int
-ok !PositiveUniqueInt([$set])->check(2);  ## Not OK, 2 is in (1,2,3)
+    Test::More::is Varchar([40])->coerce("abc"), 'abc';
+    Test::More::is Varchar([40])->coerce([qw/d e f/]), 'def';
 
-my $negative_set = Set::Scalar->new(-1,-2,-3);
+    Test::More::is MySpecialVarchar([40])->coerce("abc"), 'abc';
+    Test::More::is_deeply( MySpecialVarchar([40])->coerce([qw/d e f/]), [qw/d e f/]);
+    Test::More::is MySpecialVarchar([40])->coerce({a=>1, b=>2}), 'ab';
+}
 
-ok UniqueInt([$negative_set])->check(100);  ## Throws exception
+done_testing;