Declare::Constraints::Simple::Library::Base - Library Base Class
package My::Constraint::Library; use warnings; use strict; # this installs the base class and helper functions use Declare::Constraints::Simple-Library; # we can also automagically provide other libraries # to the importer use base 'Declare::Constraints::Simple::Library::Numericals'; # with this we define a constraint to check a value # against a serial number regular expression constraint 'SomeSerial', sub { return sub { return _true if $_[0] =~ /\d{3}-\d{3}-\d{4}/; return _false('Not in SomeSerial format'); }; }; 1;
This base class contains the common library functionalities. This includes helper functions and install mechanisms.
Installs the base classes and helper functions into the $target namespace. The %CONSTRAINT_GENERATORS package variable of that class will be used as storage for it's constraints.
$target
%CONSTRAINT_GENERATORS
Class method. Returns all constraints registered to the class.
Class method. Returns the constraint generator code reference registered under $name. The call will raise a croak if the generator could not be found.
$name
croak
Class method. This wraps the $generator in a closure that provides stack and failure-collapsing decisions.
$generator
Class method. The actual registration method, used by constraint.
constraint
Note that some of the helper functions are prefixed with _. Although this means they are internal functions, it is ok to call them, as they have a fixed API. They are not distribution internal, but library internal, and only intended to be used from inside constraints.
_
constraint 'Foo', sub { ... };
This registers a new constraint in the calling library. Note that constraints have to return result objects. To do this, you can use the helper functions "_result($bool, $msg", _true() and _false($msg).
Returns a new result object. It's validity flag will depend on the $bool argument. The $msg argument is the error message to use on failure.
$bool
$msg
Returns a non-valid result object, with it's message set to $msg.
Returns a valid result object.
Sets the current failure info to use in the stack info part.
This applies all constraints in the \@constraints array reference to the passed $value. You can optionally specify an $info string to be used in the stack of the newly created non-valid results.
\@constraints
$value
$info
Puts $value into an array reference and returns it, if it isn't already one.
This is the internal version of the general Message constraint. It sets the current overriden message to $msg and executes the $closure with @args as arguments.
Message
$closure
@args
Applies the $constraint to @args in a newly created scope named by $scope_name.
$constraint
$scope_name
Stores the given $result unter the name $name in $scope.
$result
$scope
Returns the result named $name from $scope.
Returns true only if such a result was registered already.
Declare::Constraints::Simple, Declare::Constraints::Simple::Library
Robert 'phaylon' Sedlacek <phaylon@dunkelheit.at>
<phaylon@dunkelheit.at>
This module is free software, you can redistribute it and/or modify it under the same terms as perl itself.
To install Declare::Constraints::Simple, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Declare::Constraints::Simple
CPAN shell
perl -MCPAN -e shell install Declare::Constraints::Simple
For more information on module installation, please visit the detailed CPAN module installation guide.