# NAME Params::ValidationCompiler - Build an optimized subroutine parameter validator once, use it forever # VERSION version 0.16 # SYNOPSIS use Types::Standard qw( Int Str ); use Params::ValidationCompiler qw( validation_for ); { my $validator = validation_for( params => { foo => { type => Int }, bar => { type => Str, optional => 1, }, baz => { type => Int, default => 42, }, }, ); sub foo { my %args = $validator->(@_); } } { my $validator = validation_for( params => [ { type => Int }, { type => Str, optional => 1, }, ], ); sub bar { my ( $int, $str ) = $validator->(@_); } } { my $validator = validation_for( params => [ foo => { type => Int }, bar => { type => Str, optional => 1, }, ], named_to_list => 1, ); sub baz { my ( $foo, $bar ) = $validator->(@_); } } # DESCRIPTION **This is still fairly alpha. Things could change. You have been warned.** This module creates a customized, highly efficient parameter checking subroutine. It can handle named or positional parameters, and can return the parameters as key/value pairs or a list of values. In addition to type checks, it also supports parameter defaults, optional parameters, and extra "slurpy" parameters. # EXPORTS This module has two options exports, `validation_for` and `source_for`. Both of these subs accept the same options: - params An arrayref or hashref containing a parameter specification. If you pass a hashref then the generated validator sub will expect named parameters. The `params` value should be a hashref where the parameter names are keys and the specs are the values. If you pass an arrayref and `named_to_list` is false, the validator will expect positional params. Each element of the `params` arrayref should be a parameter spec. If you pass an arrayref and `named_to_list` is false, the validator will expect named params, but will return a list of values. In this case the arrayref should contain a _list_ of key/value pairs, where parameter names are the keys and the specs are the values. Each spec can contain either a boolean or hashref. If the spec is a boolean, this indicates required (true) or optional (false). The spec hashref accepts the following keys: - type A type object. This can be a [Moose](https://metacpan.org/pod/Moose) type (from [Moose](https://metacpan.org/pod/Moose) or [MooseX::Types](https://metacpan.org/pod/MooseX::Types)), a [Type::Tiny](https://metacpan.org/pod/Type::Tiny) type, or a [Specio](https://metacpan.org/pod/Specio) type. If the type has coercions, those will always be used. - default This can either be a simple (non-reference) scalar or a subroutine reference. The sub ref will be called without any arguments (for now). - optional A boolean indicating whether or not the parameter is optional. By default, parameters are required unless you provide a default. - slurpy If this is a simple true value, then the generated subroutine accepts additional arguments not specified in `params`. By default, extra arguments cause an exception. You can also pass a type constraint here, in which case all extra arguments must be values of the specified type. - named\_to\_list If this is true, the generated subroutine will expect a list of key-value pairs or a hashref and it will return a list containing only the values. `params` must be a arrayref of key-value pairs in the order of which the values should be returned. You cannot combine `slurpy` with `named_to_list` as there is no way to know how the order in which extra values should be returned. ## validation\_for(...) This returns a subroutine that implements the specific parameter checking. This subroutine expects to be given the parameters to validate in `@_`. If all the parameters are valid, it will return the validated parameters (with defaults as appropriate), either as a list of key-value pairs or as a list of just values. If any of the parameters are invalid it will throw an exception. For validators expected named params, the generated subroutine accepts either a list of key-value pairs or a single hashref. Otherwise the validator expects a list of values. For now, you must shift off the invocant yourself. This subroutine accepts an additional parameter: - name If this is given, then the generated subroutine will be named using [Sub::Util](https://metacpan.org/pod/Sub::Util). This is strongly recommended as it makes it possible to distinguish different check subroutines when profiling or in stack traces. Note that you must install [Sub::Util](https://metacpan.org/pod/Sub::Util) yourself separately, as it is not required by this distribution, in order to avoid requiring a compiler. - name\_is\_optional If this is true, then the name is ignored when `Sub::Util` is not installed. If this is false, then passing a name when [Sub::Util](https://metacpan.org/pod/Sub::Util) cannot be loaded causes an exception. This is useful for CPAN modules where you want to set a name if you can, but you do not want to add a prerequisite on [Sub::Util](https://metacpan.org/pod/Sub::Util). ## source\_for(...) This returns a two element list. The first is a string containing the source code for the generated sub. The second is a hashref of "environment" variables to be used when generating the subroutine. These are the arguments that are passed to [Eval::Closure](https://metacpan.org/pod/Eval::Closure). # SUPPORT Bugs may be submitted through [the RT bug tracker](http://rt.cpan.org/Public/Dist/Display.html?Name=Params-ValidationCompiler) (or [bug-params-validationcompiler@rt.cpan.org](mailto:bug-params-validationcompiler@rt.cpan.org)). I am also usually active on IRC as 'drolsky' on `irc://irc.perl.org`. # DONATIONS If you'd like to thank me for the work I've done on this module, please consider making a "donation" to me via PayPal. I spend a lot of free time creating free software, and would appreciate any support you'd care to offer. Please note that **I am not suggesting that you must do this** in order for me to continue working on this particular software. I will continue to do so, inasmuch as I have in the past, for as long as it interests me. Similarly, a donation made in this way will probably not make me work on this software much more, unless I get so many donations that I can consider working on free software full time (let's all have a chuckle at that together). To donate, log into PayPal and send money to autarch@urth.org, or use the button at [http://www.urth.org/~autarch/fs-donation.html](http://www.urth.org/~autarch/fs-donation.html). # AUTHOR Dave Rolsky # CONTRIBUTOR Gregory Oschwald # COPYRIGHT AND LICENSE This software is Copyright (c) 2016 by Dave Rolsky. This is free software, licensed under: The Artistic License 2.0 (GPL Compatible)