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Method-Signatures-Simple-ParseKeyword-1.13
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/ Method::Signatures::Simple::ParseKeyword

NAME

Method::Signatures::Simple::ParseKeyword - method and func keywords using Parse::Keyword

SYNOPSIS

# -- a basic class -- #
package User;
use Method::Signatures::Simple::ParseKeyword;

method new ($class: $name, $email) {
    my $user = {
        id    => new_id(42),
        name  => $name,
        email => $email,
    };
    bless $user, $class;
}

func new_id ($seed) {
    state $id = $seed;
    $id++;
}

method name  { $self->{name};  }
method email { $self->{email}; }
1;


# -- other features -- #
# attributes
method foo : Bent { $self->{foo} }

# specify defaults
method answer ($everything = 42) { "the answer to everything is $everything" }

# change invocant name
use Method::Signatures::Simple::ParseKeyword invocant => '$this';
method foo ($bar) { $this->bar($bar) }
method bar ($class: $bar) { $class->baz($bar) }

# use a different function keyword
use Method::Signatures::Simple::ParseKeyword function_keyword => 'fun';
fun triple ($num) { 3 * $num }

# use a different method keyword
use Method::Signatures::Simple::ParseKeyword method_keyword => 'action';
action foo { $self->bar }

RATIONALE

This module provides basic method and func keywords with simple signatures. It's intentionally simple, and is supposed to be a stepping stone for its bigger brothers MooseX::Method::Signatures and Method::Signatures. It only has a small benefit over regular subs, so if you want more features, look at those modules. But if you're looking for a small amount of syntactic sugar, this might just be enough.

This module is a port from Devel::Declare to Parse::Keyword. This utilizes the parsing API of the perl core, so should be more stable.

FEATURES

  • invocant

    The method keyword automatically injects the annoying my $self = shift; for you. You can rename the invocant with the first argument, followed by a colon:

    method ($this:) {}
method ($this: $that) {}

    The func keyword doesn't inject an invocant, but does do the signature processing below:

    func ($that) {}

  • signature

    The signature ($sig) is transformed into "my ($sig) = \@_;". That way, we mimic perl's usual argument handling.

    method foo ($bar, $baz, %opts) {
func xyzzy ($plugh, @zorkmid) {

# becomes

sub foo {
    my $self = shift;
    my ($bar, $baz, %opts) = @_;

sub xyzzy {
    my ($plugh, @zorkmid) = @_;

ADVANCED CONFIGURATION

You can change the keywords and the default invocant with import arguments. These changes affect the current scope.

  • change the invocant name

    use Method::Signatures::Simple::ParseKeyword invocant => '$this';
method x { $this->{x} }
method y { $this->{y} }

# and this of course still works:
method z ($self:) { $self->{z} }

  • change the keywords

    You can install a different keyword (instead of the default 'method' and 'func'), by passing names to the use line:

    use Method::Signatures::Simple::ParseKeyword method_keyword   => 'action',
                               function_keyword => 'thing';

action foo ($some, $args) { ... }
thing bar ($whatever) { ... }

    One benefit of this is that you can use this module together with e.g. MooseX::Declare:

    # untested
use MooseX::Declare;

class Foo {
    use Method::Signatures::Simple::ParseKeyword method_keyword => 'routine';
    method x (Int $x) { ... }    # from MooseX::Method::Signatures
    routine y ($y) { ... }       # from this module
}

    If you specify neither method_keyword nor function_keyword, then we default to injecting method and func. If you only specify one of these options, then we only inject that one keyword into your scope.

    Examples:

    # injects 'method' and 'func'
use Method::Signatures::Simple::ParseKeyword;

# only injects 'action'
use Method::Signatures::Simple::ParseKeyword method_keyword => 'action';

# only injects 'procedure'
use Method::Signatures::Simple::ParseKeyword function_keyword => 'procedure';

# injects 'action' and 'function'
use Method::Signatures::Simple::ParseKeyword method_keyword   => 'action',
                               function_keyword => 'function';

  • install several keywords

    You're not limited to a single use line, so you can install several keywords with the same semantics as 'method' into the current scope:

    use Method::Signatures::Simple::ParseKeyword; # provides 'method' and 'func'
use Method::Signatures::Simple::ParseKeyword method_keyword => 'action';

method x { ... }
func y { ... }
action z { ... }

AUTHOR

Rhesa Rozendaal, <rhesa at cpan.org>

BUGS

Please report any bugs or feature requests to bug-method-signatures-simple at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Method-Signatures-Simple-ParseKeyword. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

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

perldoc Method::Signatures::Simple::ParseKeyword

You can also look for information at:

ACKNOWLEDGEMENTS

  • MSTROUT

    For writing Devel::Declare and providing the core concepts.

  • MSCHWERN

    For writing Method::Signatures and publishing about it. This is what got my attention.

  • FLORA

    For helping me abstracting the Devel::Declare bits and suggesting improvements.

  • CHIPS

    For suggesting we add a 'func' keyword.

SEE ALSO

Parse::Keyword, Method::Signatures, MooseX::Method::Signatures.

COPYRIGHT & LICENSE

Copyright 2022 Rhesa Rozendaal, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.