X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMouse%2FMeta%2FTypeConstraint.pm;h=77a8706369742a42231860637c25115c2046ceea;hb=66e3df7a8d3d839b53f6fc3af8f4bad6fc27fefe;hp=caeb98081d8ca420bc2f920c84a6abcf2823cfae;hpb=e98220ab1bfe3cafe6121d5c91c1547bd93199fb;p=gitmo%2FMouse.git

diff --git a/lib/Mouse/Meta/TypeConstraint.pm b/lib/Mouse/Meta/TypeConstraint.pm
index caeb980..77a8706 100644
--- a/lib/Mouse/Meta/TypeConstraint.pm
+++ b/lib/Mouse/Meta/TypeConstraint.pm
@@ -1,77 +1,190 @@
 package Mouse::Meta::TypeConstraint;
-use strict;
-use warnings;
-
-use overload
-    '""'     => sub { shift->{name} },   # stringify to tc name
-    fallback => 1;
-
-use Carp qw(confess);
-use Scalar::Util qw(blessed reftype);
-
-use Mouse::Util qw(:meta);
-
-my $null_check = sub { 1 };
+use Mouse::Util qw(:meta); # enables strict and warnings
 
 sub new {
-    my($class, %args) = @_;
+    my $class = shift;
+    my %args  = @_ == 1 ? %{$_[0]} : @_;
 
     $args{name} = '__ANON__' if !defined $args{name};
 
-    my $check = $args{_compiled_type_constraint} || $args{constraint};
+    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};       # 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",
+                    );
+            }
+            else {
+                $type_parameter = undef;
+            }
+        }
+    }
+
+    my $check;
 
-    if(blessed($check)){
-        Carp::cluck("'constraint' must be a CODE reference");
-        $check = $check->{_compiled_type_constraint};
+    if($check = delete $args{optimized}) { # likely to be builtins
+        $args{hand_optimized_type_constraint} = $check;
+        $args{compiled_type_constraint}       = $check;
+    }
+    elsif(defined $type_parameter) { # parameterizing
+        my $generator = $args{constraint_generator}
+            || $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 { # common cases
+        $check = $args{constraint};
     }
 
     if(defined($check) && ref($check) ne 'CODE'){
-        confess("Type constraint for $args{name} is not a CODE reference");
+        $class->throw_error(
+            "Constraint for $args{name} is not a CODE reference");
     }
 
     my $self = bless \%args, $class;
-    $self->{_compiled_type_constraint} ||= $self->_compile();
+    $self->compile_type_constraint()
+        if !$args{hand_optimized_type_constraint};
+
+    if($args{type_constraints}) { # union types
+        foreach my $type(@{$self->{type_constraints}}){
+            if($type->has_coercion){
+                # set undef for has_coercion()
+                $self->{_compiled_type_coercion} = undef;
+                last;
+            }
+        }
+    }
 
     return $self;
 }
 
-sub create_child_type{
+sub create_child_type {
     my $self = shift;
-    # XXX: FIXME
-    return ref($self)->new(
-        %{$self},                            # pass the inherit parent attributes
-        _compiled_type_constraint => undef,  # ... other than compiled type constraint
-        @_,                                  # ... and args
-        parent => $self                      # ... and the parent
-   );
+    return ref($self)->new(@_, parent => $self);
 }
 
-sub name    { $_[0]->{name}    }
-sub parent  { $_[0]->{parent}  }
-sub message { $_[0]->{message} }
+sub name;
+sub parent;
+sub message;
+sub has_coercion;
+
+sub check;
+
+sub type_parameter;
+sub __is_parameterized;
+
+sub _compiled_type_constraint;
+sub _compiled_type_coercion;
 
-sub check {
+sub compile_type_constraint;
+
+
+sub _add_type_coercions { # ($self, @pairs)
     my $self = shift;
-    $self->{_compiled_type_constraint}->(@_);
-}
 
-sub validate {
-    my ($self, $value) = @_;
-    if ($self->{_compiled_type_constraint}->($value)) {
-        return undef;
+    if(exists $self->{type_constraints}){ # union type
+        $self->throw_error(
+            "Cannot add additional type coercions to Union types '$self'");
     }
-    else {
-        $self->get_message($value);
+
+    my $coercion_map = ($self->{coercion_map} ||= []);
+    my %has          = map{ $_->[0]->name => undef } @{$coercion_map};
+
+    for(my $i = 0; $i < @_; $i++){
+        my $from   = $_[  $i];
+        my $action = $_[++$i];
+
+        if(exists $has{$from}){
+            $self->throw_error("A coercion action already exists for '$from'");
+        }
+
+        my $type = Mouse::Util::TypeConstraints::find_or_parse_type_constraint($from)
+            or $self->throw_error(
+                "Could not find the type constraint ($from) to coerce from");
+
+        push @{$coercion_map}, [ $type => $action ];
     }
+
+    $self->{_compiled_type_coercion} = undef;
+    return;
 }
 
-sub assert_valid {
-    my ($self, $value) = @_;
+sub _compiled_type_coercion {
+    my($self) = @_;
+
+    my $coercion = $self->{_compiled_type_coercion};
+    return $coercion if defined $coercion;
 
-    my $error = $self->validate($value);
-    return 1 if ! defined $error;
+    if(!$self->{type_constraints}) {
+        my @coercions;
+        foreach my $pair(@{$self->{coercion_map}}) {
+            push @coercions,
+                [ $pair->[0]->_compiled_type_constraint, $pair->[1] ];
+        }
 
-    confess($error);
+        $coercion = sub {
+           my($thing) = @_;
+           foreach my $pair (@coercions) {
+                #my ($constraint, $converter) = @$pair;
+                if ($pair->[0]->($thing)) {
+                  local $_ = $thing;
+                  return $pair->[1]->($thing);
+                }
+           }
+           return $thing;
+        };
+    }
+    else { # for union type
+        my @coercions;
+        foreach my $type(@{$self->{type_constraints}}){
+            if($type->has_coercion){
+                push @coercions, $type;
+            }
+        }
+        if(@coercions){
+            $coercion = sub {
+                my($thing) = @_;
+                foreach my $type(@coercions){
+                    my $value = $type->coerce($thing);
+                    return $value if $self->check($value);
+                }
+                return $thing;
+            };
+        }
+    }
+
+    return( $self->{_compiled_type_coercion} = $coercion );
+}
+
+sub coerce {
+    my $self = shift;
+    return $_[0] if $self->check(@_);
+
+    my $coercion = $self->_compiled_type_coercion
+        or $self->throw_error("Cannot coerce without a type coercion");
+    return  $coercion->(@_);
 }
 
 sub get_message {
@@ -81,78 +194,77 @@ sub get_message {
         return $msg->($value);
     }
     else {
-        $value = ( defined $value ? overload::StrVal($value) : 'undef' );
-        return
-            "Validation failed for '"
-          . $self->name
-          . "' failed with value $value";
+        if(not defined $value) {
+            $value = 'undef';
+        }
+        elsif( ref($value) && defined(&overload::StrVal) ) {
+            $value = overload::StrVal($value);
+        }
+        return "Validation failed for '$self' with value $value";
     }
 }
 
-sub is_a_type_of{
+sub is_a_type_of {
     my($self, $other) = @_;
 
     # ->is_a_type_of('__ANON__') is always false
-    return 0 if !blessed($other) && $other eq '__ANON__';
+    return 0 if !ref($other) && $other eq '__ANON__';
 
     (my $other_name = $other) =~ s/\s+//g;
 
     return 1 if $self->name eq $other_name;
 
     if(exists $self->{type_constraints}){ # union
-        foreach my $type(@{$self->{type_constraints}}){
+        foreach my $type(@{$self->{type_constraints}}) {
             return 1 if $type->name eq $other_name;
         }
     }
 
-    for(my $parent = $self->parent; defined $parent; $parent = $parent->parent){
-        return 1 if $parent->name eq $other_name;
+    for(my $p = $self->parent; defined $p; $p = $p->parent) {
+        return 1 if $p->name eq $other_name;
     }
 
     return 0;
 }
 
-sub _compile{
-    my($self) = @_;
+# See also Moose::Meta::TypeConstraint::Parameterizable
+sub parameterize {
+    my($self, $param, $name) = @_;
 
-    # add parents first
-    my @checks;
-    for(my $parent = $self->parent; defined $parent; $parent = $parent->parent){
-        if($parent->{constraint}){
-            push @checks, $parent->{constraint};
-         }
-         elsif($parent->{_compiled_type_constraint} && $parent->{_compiled_type_constraint} != $null_check){
-            # hand-optimized constraint
-            push @checks, $parent->{_compiled_type_constraint};
-            last;
-        }
-    }
-    # then add child
-    if($self->{constraint}){
-        push @checks, $self->{constraint};
+    if(!ref $param){
+        require Mouse::Util::TypeConstraints;
+        $param = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($param);
     }
 
-    if(@checks == 0){
-        return $null_check;
-    }
-    elsif(@checks == 1){
-        my $c = $checks[0];
-        return sub{
-            my(@args) = @_;
-            local $_ = $args[0];
-            return $c->(@args);
-        };
-    }
-    else{
-        return sub{
-            my(@args) = @_;
-            local $_ = $args[0];
-            foreach my $c(@checks){
-                return undef if !$c->(@args);
-            }
-            return 1;
-        };
+    $name ||= sprintf '%s[%s]', $self->name, $param->name;
+    return Mouse::Meta::TypeConstraint->new(
+        name           => $name,
+        parent         => $self,
+        type_parameter => $param,
+    );
+}
+
+sub assert_valid {
+    my ($self, $value) = @_;
+
+    if(!$self->check($value)){
+        $self->throw_error($self->get_message($value));
     }
+    return 1;
+}
+
+# overloading stuff
+
+sub _as_string { $_[0]->name } # overload ""
+sub _identity;                 # overload 0+
+
+sub _unite { # overload infix:<|>
+    my($lhs, $rhs) = @_;
+    require Mouse::Util::TypeConstraints;
+    return Mouse::Util::TypeConstraints::_find_or_create_union_type(
+        $lhs,
+        Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($rhs),
+    );
 }
 
 1;
@@ -162,23 +274,44 @@ __END__
 
 Mouse::Meta::TypeConstraint - The Mouse Type Constraint metaclass
 
-=head1 DESCRIPTION
+=head1 VERSION
 
-For the most part, the only time you will ever encounter an
-instance of this class is if you are doing some serious deep
-introspection. This API should not be considered final, but
-it is B<highly unlikely> that this will matter to a regular
-Mouse user.
+This document describes Mouse version 0.88
+
+=head1 DESCRIPTION
 
-Don't use this.
+This class represents a type constraint, including built-in
+type constraints, union type constraints, parameterizable/
+parameterized type constraints, as well as custom type
+constraints
 
 =head1 METHODS
 
-=over 4
+=over
+
+=item C<< Mouse::Meta::TypeConstraint->new(%options) >>
+
+=item C<< $constraint->name >>
+
+=item C<< $constraint->parent >>
+
+=item C<< $constraint->constraint >>
+
+=item C<< $constraint->has_coercion >>
+
+=item C<< $constraint->message >>
+
+=item C<< $constraint->is_a_type_of($name or $object) >>
+
+=item C<< $constraint->coerce($value) >>
+
+=item C<< $constraint->check($value) >>
+
+=item C<< $constraint->assert_valid($value) >>
 
-=item B<new>
+=item C<< $constraint->get_message($value) >>
 
-=item B<name>
+=item C<< $constraint->create_child_type(%options) >>
 
 =back