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https://github.com/nigelhorne/params-get

Get the parameters to a subroutine in any way you want
https://github.com/nigelhorne/params-get

cpan cpan-module parameters perl perl-module perl5 perl5-module

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Get the parameters to a subroutine in any way you want

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# NAME

Params::Get - Get the parameters to a subroutine in any way you want

# VERSION

Version 0.14

# DESCRIPTION

Exports a single function, `get_params`, which returns a given value.

When used hand-in-hand with [Params::Validate::Strict](https://metacpan.org/pod/Params%3A%3AValidate%3A%3AStrict) and [Return::Set](https://metacpan.org/pod/Return%3A%3ASet),
you should be able to formally specify the input and output sets for a method.

# SYNOPSIS

use Params::Get;
use Params::Validate::Strict;

sub where_am_i
{
my $params = Params::Validate::Strict::validate_strict({
args => Params::Get::get_params(undef, \@_),
schema => {
'latitude' => {
type => 'number',
min => -90,
max => 90
}, 'longitude' => {
type => 'number',
min => -180,
max => 180
}
}
});

print 'You are at ', $params->{'latitude'}, ', ', $params->{'longitude'}, "\n";
}

where_am_i(latitude => 0.3, longitude => 124);
where_am_i({ latitude => 3.14, longitude => -155 });

# METHODS

## get\_params

Parse the arguments given to a function.
Processes arguments passed to methods and ensures they are in a usable format,
allowing the caller to call the function in any way that they want
e.g. \`foo('bar')\`, \`foo(arg => 'bar')\`, \`foo({ arg => 'bar' })\` all mean the same
when called with

get_params('arg', @_);

or

get_params('arg', \@_);

Some people like this sort of model, which is also supported.

use MyClass;

my $str = 'hello world';
my $obj = MyClass->new($str, { type => 'string' });

package MyClass;

use Params::Get;

sub new {
my $class = shift;
my $rc = Params::Get::get_params('value', \@_);

return bless $rc, $class;
}

## The `$default` Parameter

The first argument is the `$default` parameter controls how single-argument calls are interpreted and provides
a default key name for parameter extraction in those cases.

When no arguments are provided with a defined `$default`:

get_params('required'); # Throws usage error

The function requires either arguments or an undefined `$default`.

### Usage Examples

- Simple scalar parameter:

sub set_country {
my $params = get_params('country', @_);
# Accepts: set_country('US')
# Returns: { country => 'US' }
}

- Object constructor with options:

sub new {
my $class = shift;
my $params = get_params('value', @_);
# Accepts: MyClass->new($object)
# Accepts: MyClass->new($object, { option => 'value' })
# Returns: { value => $object } or { value => $object, option => 'value' }
}

- Hash parameter:

sub configure {
my $params = get_params('config', @_);
# Accepts: configure({ db => 'mysql', host => 'localhost' })
# Returns: { config => { db => 'mysql', host => 'localhost' } }
}

- Without default (named parameters only):

sub process {
my $params = get_params(undef, @_);
# Accepts: process(name => 'John', age => 30)
# Returns: { name => 'John', age => 30 }
}

### Caveats

- When `$default` is defined and no arguments are provided, an error is thrown
- There's no way to specify that a default parameter is optional
- Single hash references always bypass the default parameter naming

# AUTHOR

Nigel Horne, ``

# BUGS

Sometimes giving an array ref rather than array fails.

# SEE ALSO

- [Params::Smart](https://metacpan.org/pod/Params%3A%3ASmart)
- [Params::Validate::Strict](https://metacpan.org/pod/Params%3A%3AValidate%3A%3AStrict)
- [Return::Set](https://metacpan.org/pod/Return%3A%3ASet)
- [Test Dashboard](https://nigelhorne.github.io/Params-Get/coverage/)

# SUPPORT

This module is provided as-is without any warranty.

Please report any bugs or feature requests to `bug-params-get at rt.cpan.org`,
or through the web interface at
[http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Params-Get](http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Params-Get).
I will be notified, and then you'll
automatically be notified of progress on your bug as I make changes.

You can find documentation for this module with the perldoc command.

perldoc Params::Get

You can also look for information at:

- MetaCPAN

[https://metacpan.org/dist/Params-Get](https://metacpan.org/dist/Params-Get)

- RT: CPAN's request tracker

[https://rt.cpan.org/NoAuth/Bugs.html?Dist=Params-Get](https://rt.cpan.org/NoAuth/Bugs.html?Dist=Params-Get)

- CPAN Testers' Matrix

[http://matrix.cpantesters.org/?dist=Params-Get](http://matrix.cpantesters.org/?dist=Params-Get)

- CPAN Testers Dependencies

[http://deps.cpantesters.org/?module=Params::Get](http://deps.cpantesters.org/?module=Params::Get)

# LICENCE AND COPYRIGHT

Copyright 2025-2026 Nigel Horne.

Usage is subject to the GPL2 licence terms.
If you use it,
please let me know.