From: John Napiorkowski Date: Sat, 16 May 2009 21:32:11 +0000 (+0000) Subject: more specification and documentation X-Git-Tag: 0.01~24 X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=5964b3cacce00a1797717802e007fbb7cadc95fb;p=gitmo%2FMooseX-Dependent.git more specification and documentation --- diff --git a/Makefile.PL b/Makefile.PL index f35b4c5..66ed7cb 100644 --- a/Makefile.PL +++ b/Makefile.PL @@ -1,9 +1,9 @@ use inc::Module::Install; ## All the required meta information -name 'MooseX-Types-Dependent'; -all_from 'lib/MooseX/Types/Dependent.pm'; -abstract 'Moose Type Constraint for creating Dependent Types Constraints'; +name 'MooseX-Dependent'; +all_from 'lib/MooseX/Dependent.pm'; +abstract 'Moose extensions to let you use dependent types in your classes'; author 'John Napiorkowski '; license 'perl'; @@ -20,7 +20,7 @@ build_requires 'Test::Pod' => '1.14'; build_requires 'Test::Pod::Coverage' => '1.08'; ## Build README -system 'pod2text lib/MooseX/Types/Dependent.pm > README' +system 'pod2text lib/MooseX/Dependent.pm > README' if -e 'MANIFEST.SKIP'; ## Instructions to Module::Install @@ -28,4 +28,4 @@ auto_install; tests_recursive; WriteAll; -1; +1; \ No newline at end of file diff --git a/lib/MooseX/Dependent.pm b/lib/MooseX/Dependent.pm new file mode 100644 index 0000000..6c8b293 --- /dev/null +++ b/lib/MooseX/Dependent.pm @@ -0,0 +1,109 @@ +package MooseX::Dependent; + +use 5.008; + +use strict; +use warnings; + +our $VERSION = '0.01'; +our $AUTHORITY = 'cpan:JJNAPIORK'; + +=head1 NAME + +MooseX::Dependent - Dependent L constraints and L attributes + +=head1 SYNOPSIS + +Given some L declared as: + + package MyApp::Types; + + use MooseX::Types::Moose qw(Object, Int); + use MooseX::Dependent::Types qw(Dependent); + use Moosex::Types -declare => [qw(Set UniqueID)]; + + subtype Set, + as Object, + where { + shift->can('find'); + }; + + subtype UniqueID, + as Dependent[Int, Set], + where { + my ($int, $set) = @_; + return $set->find($int) ? 0:1; + }; + +Assuming 'Set' is a class that creates and manages sets of values (lists of +unique but unordered values) with a method '->find($n)', which returns true when +$n is a member of the set and which you instantiate like so: + + my $set_obj = Set->new(1,2,3,4,5); ## 1..5 are member of Set $set_obj' + +You can then use this $set_obj as a parameter on the previously declared type +constraint 'UniqueID'. This $set_obj become part of the constraint (you can't +actually use the constraint without it.) + + UniqueID[$set_obj]->check(1); ## Not OK, since one isn't unique in $set_obj + UniqueID[$set_obj]->check(100); ## OK, since 100 isn't in the set. + +Additionally, you can use these dependent types on your L based classes +and set the dependency target to the value of another attribute or method: + + TDB: Following is tentative + + package MyApp::MyClass; + + use Moose; + use MooseX::Dependent (or maybe a role, or traits...?) + use MooseX::Types::Moose qw(); + use MyApp::Types qw(UniqueID Set); + + has people => (is=>'ro', isa=>Set, required=>1); + has id => (is=>'ro', isa=>UniqueID, required=>1); + +Please see the test cases for more examples. + +=head1 DESCRIPTION + +A dependent type is a type constraint whose validity is dependent on a second +value. You defined the dependent type constraint with a primary type constraint +(such as 'Int') a 'constraining' value type constraint (such as a 'Set' object) +and a coderef (such as a 'where' clause in your type constraint declaration) +which will compare the incoming value to be checked with a value that conforms +to the constraining type constraint. + +Once created, you can use dependent types directly, or in your L based +attributes and methods (if you are using L). Attribute traits +are available to make it easy to assign the dependency to the value of another +attribute or another method. + +=head1 TYPE CONSTRAINTS + +All type constraints are defined in L. Please see +that class for more documentation and examples of how to create type constraint +libraries using dependent types. + +=cut + +=head1 ATTRIBUTE TRAITS + + TBD + +=head1 SEE ALSO + +L, L, L + +=head1 AUTHOR + +John Napiorkowski, C<< >> + +=head1 COPYRIGHT & LICENSE + +This program is free software; you can redistribute it and/or modify +it under the same terms as Perl itself. + +=cut + +1; diff --git a/lib/MooseX/Dependent/Types.pm b/lib/MooseX/Dependent/Types.pm index 5b3f273..43b2e6e 100644 --- a/lib/MooseX/Dependent/Types.pm +++ b/lib/MooseX/Dependent/Types.pm @@ -1,115 +1,201 @@ -package MooseX::Types::Dependent; +package MooseX::Dependent::Types; use 5.008; use Moose::Util::TypeConstraints; -use MooseX::Meta::TypeConstraint::Dependent; -use MooseX::Types -declare => [qw(Depending)]; +use MooseX::Dependent::Meta::TypeConstraint::Parameterizable; +use MooseX::Types -declare => [qw(Dependent)]; our $VERSION = '0.01'; our $AUTHORITY = 'cpan:JJNAPIORK'; =head1 NAME -MooseX::Types::Dependent - L constraints that depend on values. +MooseX::Dependent::Types - L constraints that depend on values. =head1 SYNOPSIS - subtype UniqueInt, - as Depending[ - Int, - sub { - shift->exists(shift) ? 0:1; - }, - Set, - ]; - - subtype UniqueInt, - as Depending { - shift->exists(shift) ? 0:1; - } [Int, Set]; - -Please see the test cases for more examples. - -=head1 DEFINITIONS - -The following is a list of terms used in this documentation. - -=head2 Dependent Type Constraint - -=head2 Check Value +Within your L declared library module: -=head2 Constraining Type Constraint - -=head2 Constraining Value + use MooseX::Dependent::Types qw(Dependent); + + subtype UniqueID, + as Dependent[Int, Set], + where { + my ($int, $set) = @_; + return $set->find($int) ? 0:1; + }; =head1 DESCRIPTION -A dependent type is a type constraint whose validity is dependent on a second -value. You defined the dependent type constraint with a primary type constraint -(such as 'Int') a 'constraining' value type constraint (such as a Set object) -and a coderef which will compare the incoming value to be checked with a value -that conforms to the constraining type constraint. Typically there should be a -comparision operator between the check value and the constraining value - -=head2 Subtyping a Dependent type constraints - -TDB: Need discussion and examples. - +A L library for creating dependent types. A dependent type +constraint for all intents and uses is a subclass of a parent type, but adds a +secondary type parameter which is available to constraint callbacks (such as +inside the 'where' clause) or in the coercions. + +This allows you to create a type that has additional runtime advice, such as a +set of numbers within which another number must be unique, or allowable ranges +for a integer, such as in: + + subtype Range, + as Dict[max=>Int, min=>Int], + where { + my ($range) = @_; + return $range->{max} > $range->{min}; + }; + + subtype RangedInt, + as Dependent[Int, Range], + where { + my ($value, $range) = @_; + return ($value >= $range->{min} && + $value =< $range->{max}); + }; + + RangedInt[{min=>10,max=>100}]->check(50); ## OK + RangedInt[{min=>50, max=>75}]->check(99); ## Not OK, 99 exceeds max + RangedInt[{min=>99, max=>10}]->check(10); ## Not OK, not a valid Range! + +Please note that for ArrayRef or HashRef dependent type constraints, as in the +example above, as a convenience we automatically ref the incoming type +parameters, so that the above could also be written as: + + RangedInt[min=>10,max=>100]->check(50); ## OK + RangedInt[min=>50, max=>75]->check(99); ## Not OK, 99 exceeds max + RangedInt[min=>99, max=>10]->check(10); ## Not OK, not a valid Range! + +This is the preferred syntax, as it improve readability and adds to the +conciseness of your type constraint declarations. An exception wil be thrown if +your type parameters don't match the required reference type. + +==head2 Subtyping a Dependent type constraints + +When subclassing a dependent type you must be careful to match either the +required type parameter type constraint, or if re-parameterizing, the new +type constraints are a subtype of the parent. For example: + + subtype RangedInt, + as Dependent[Int, Range], + where { + my ($value, $range) = @_; + return ($value >= $range->{min} && + $value =< $range->{max}); + }; + +Example subtype with additional constraints: + + subtype PositiveRangedInt, + as RangedInt, + where { + shift >= 0; + }; + +Or you could have done the following instead (example of re-paramterizing) + + ## Subtype of Int for positive numbers + subtype PositiveInt, + as Int, + where { + shift >= 0; + }; + + ## subtype Range to re-parameterize Range with subtypes + subtype PositveRange, + as Range[max=>PositiveInt, min=>PositiveInt]; + + ## create subtype via reparameterizing + subtype PositiveRangedInt, + as RangedInt[PositveRange]; + +Notice how re-parameterizing the dependent type 'RangedInt' works slightly +differently from re-parameterizing 'PositiveRange'? Although it initially takes +two type constraint values to declare a dependent type, should you wish to +later re-parameterize it, you only use a subtype of the second type parameter +(the dependent type constraint) since the first type constraint sets the parent +type for the dependent type. In other words, given the example above, a type +constraint of 'RangedInt' would have a parent of 'Int', not 'Dependent' and for +all intends and uses you could stick it wherever you'd need an Int. + + subtype NameAge, + as Tuple[Str, Int]; + + ## re-parameterized subtypes of NameAge containing a Dependent Int + subtype NameBetween18and35Age, + as NameAge[ + Str, + PositiveRangedInt[min=>18,max=>35], + ]; + +One caveat is that you can't stick an unparameterized dependent type inside a +structure, such as L since that would require the +ability to convert a 'containing' type constraint into a dependent type, which +is a capacity we current don't have. + =head2 Coercions -TBD: Need discussion and example of coercions working for both the -constrainted and dependent type constraint. + TBD: Need discussion and example of coercions working for both the + constrainted and dependent type constraint. + + subtype OlderThanAge, + as Dependent[Int, Dict[older_than=>Int]], + where { + my ($value, $dict) = @_; + return $value > $dict->{older_than} ? 1:0; + }; + +Which should work like: + + OlderThanAge[{older_than=>25}]->check(39); ## is OK + + coerce OlderThanAge, + from Tuple[Int, Int], + via { + my ($int, $int); + return [$int, {older_than=>$int}]; + }; =head2 Recursion Newer versions of L support recursive type constraints. That is you can include a type constraint as a contained type constraint of itself. Recursion is support in both the dependent and constraining type constraint. For -example: +example, if we assume an Object hierarchy like Food -> [Grass, Meat] + + TODO: DOES THIS EXAMPLE MAKE SENSE? + + subtype Food, + as Dependent[Food, Food], + where { + my ($value, $allowed_food_type) = @_; + return $value->isa($allowed_food_type); + }; + + my $grass = Food::Grass->new; + my $meat = Food::Meat->new; + my $vegetarian = Food[$grass]; + + $vegetarian->check($grass); ## Grass is the allowed food of a vegetarian + $vegetarian->check($meat); ## BANG, vegetarian can't eat meat! =head1 TYPE CONSTRAINTS This type library defines the following constraints. -=head2 Depending[$dependent_tc, $codref, $constraining_tc] - -Create a subtype of $dependent_tc that is constrainted by a value that is a -valid $constraining_tc using $coderef. For example: - - subtype GreaterThanInt, - as Depending[ - Int, - sub { - my($constraining_value, $check_value) = @_; - return $constraining_value > $check_value ? 1:0; - }, - Int, - ]; +=head2 Dependent[ParentTypeConstraint, DependentValueTypeConstraint] -Note that the coderef is passed the constraining value and the check value as an -Array NOT an ArrayRef. +Create a subtype of ParentTypeConstraint with a dependency on a value that can +pass the DependentValueTypeConstraint. If DependentValueTypeConstraint is empty +we default to the 'Any' type constraint (see L). -This would create a type constraint that takes an integer and checks it against -a second integer, requiring that the check value is greater. For example: - - GreaterThanInt->check([5,10]); ## Fails, 5 is less than 10 - GreaterThanInt->check(['a',10]); ## Fails, 'a' is not an Int. - GreaterThanInt->check([5,'b']); ## Fails, 'b' is not an Int either. - GreaterThanInt->check([10,5]); ## Success, 10 is greater than 5. - -=head1 EXAMPLES - -Here are some additional example usage for structured types. All examples can -be found also in the 't/examples.t' test. Your contributions are also welcomed. - -TBD +This creates a type constraint which must be further parameterized at later time +before it can be used to ->check or ->validate a value. Attempting to do so +will cause an exception. =cut Moose::Util::TypeConstraints::get_type_constraint_registry->add_type_constraint( - MooseX::Meta::TypeConstraint::Dependent->new( - name => "MooseX::Types::Dependent::Depending" , + MooseX::Dependent::Meta::TypeConstraint::Parameterizable->new( + name => 'MooseX::Dependent::Types::Dependent', parent => find_type_constraint('ArrayRef'), constraint_generator=> sub { my ($dependent_val, $callback, $constraining_val) = @_; @@ -118,26 +204,6 @@ Moose::Util::TypeConstraints::get_type_constraint_registry->add_type_constraint( ) ); -=head1 SEE ALSO - -The following modules or resources may be of interest. - -L, L, L, -L - -=head1 TODO - -Here's a list of stuff I would be happy to get volunteers helping with: - -=over 4 - -=item Examples - -Examples of useful code with both POD and ideally a test case to show it -working. - -=back - =head1 AUTHOR John Napiorkowski, C<< >>