Params::ValidationCompiler(3pm) - phpMan

Params::ValidationCompiler(3pm)User Contributed Perl DocumentationParams::ValidationCompiler(3pm)

NAME
Params::ValidationCompiler - Build an optimized subroutine parameter validator once, use
it forever

VERSION
version 0.30

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 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.

PARAMETERS
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 true, 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:

o type

A type object. This can be a Moose type (from Moose or MooseX::Types), a Type::Tiny
type, or a Specio type.

If the type has coercions, those will always be used.

o 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).

o 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 values. The "params" you pass must be a
arrayref of key-value pairs. The order of these pairs determines the order in which values
are returned.

You cannot combine "slurpy" with "named_to_list" as there is no way to know how to order
the extra return values.

return_object
If this is true, the generated subroutine will return an object instead of a hashref. You
cannot set this option to true if you set either or "slurpy" or "named_to_list".

The object's methods correspond to the parameter names passed to the subroutine. While
calling methods on an object is slower than accessing a hashref, the advantage is that if
you typo a parameter name you'll get a helpful error.

If you have Class::XSAccessor installed then this will be used to create the class's
methods, which makes it fairly fast.

The returned object is in a generated class. Do not rely on this class name being anything
in specific, and don't check this object using "isa", "DOES", or anything similar.

When "return_object" is true, the parameter spec hashref also accepts to the following
additional keys:

o getter

Use this to set an explicit getter method name for the parameter. By default the
method name will be the same as the parameter name. Note that if the parameter name is
not a valid sub name, then you will get an error compiling the validation sub unless
you specify a getter for the parameter.

o predicate

Use this to ask for a predicate method to be created for this parameter. The predicate
method returns true if the parameter was passed and false if it wasn't. Note that this
is only useful for optional parameters, but you can ask for a predicate for any
parameter.

EXPORTS
The exported subs are:

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 the following additional parameters:

o name

If this is given, then the generated subroutine will be named using Sub::Util. This is
strongly recommended as it makes it possible to distinguish different check
subroutines when profiling or in stack traces.

This name will also be used in some exception messages, even if Sub::Util is not
available.

Note that you must install Sub::Util yourself separately, as it is not required by
this distribution, in order to avoid requiring a compiler.

o 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 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.

o debug

Sets the "EVAL_CLOSURE_PRINT_SOURCE" environment variable to true before calling
"Eval::Closure::eval_closure()". This causes the source of the subroutine to be
printed before it's "eval"'d.

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.

SUPPORT
Bugs may be submitted at
<https://github.com/houseabsolute/Params-ValidationCompiler/issues>.

I am also usually active on IRC as 'autarch' on "irc://irc.perl.org".

SOURCE
The source code repository for Params-ValidationCompiler can be found at
<https://github.com/houseabsolute/Params-ValidationCompiler>.

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 AT urth.org, or use the button at
<http://www.urth.org/~autarch/fs-donation.html>.

AUTHOR
Dave Rolsky <autarch AT urth.org>

CONTRIBUTORS
o Gregory Oschwald <goschwald AT maxmind.com>

o Gregory Oschwald <oschwald AT gmail.com>

o Tomasz Konojacki <me AT xenu.pl>

This is free software, licensed under:

The Artistic License 2.0 (GPL Compatible)

The full text of the license can be found in the LICENSE file included with this
distribution.

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