/ 
Sub-Meta-0.09
River stage one • 1 direct dependent • 1 total dependent
/ Sub::Meta

NAME

Sub::Meta - handle subroutine meta information

SYNOPSIS

use Sub::Meta;

sub hello($) :mehtod { }
my $meta = Sub::Meta->new(sub => \&hello);
$meta->subname; # => hello

$meta->sub;        # \&hello
$meta->subname;    # hello
$meta->fullname    # main::hello
$meta->stashname   # main
$meta->file        # path/to/file.pl
$meta->line        # 5
$meta->is_constant # !!0
$meta->prototype   # $
$meta->attribute   # ['method']
$meta->is_method   # undef
$meta->parameters  # undef
$meta->returns     # undef
$meta->display     # 'sub hello'

# setter
$meta->set_subname('world');
$meta->subname; # world
$meta->fullname; # main::world

# apply to sub
$meta->apply_prototype('$@');
$meta->prototype; # $@
Sub::Util::prototype($meta->sub); # $@

And you can hold meta information of parameter type and return type. See also Sub::Meta::Parameters and Sub::Meta::Returns.

$meta->set_parameters(args => ['Str']));
$meta->parameters->args; # [ Sub::Meta::Param->new({ type => 'Str' }) ]

$meta->set_args(['Str']);
$meta->args; # [ Sub::Meta::Param->new({ type => 'Str' }) ]

$meta->set_returns('Str');
$meta->returns->scalar; # 'Str'
$meta->returns->list;   # 'Str'

And you can compare meta informations:

my $other = Sub::Meta->new(subname => 'hello');
$meta->is_same_interface($other); # 1
$meta eq $other; # 1

DESCRIPTION

Sub::Meta provides methods to handle subroutine meta information. In addition to information that can be obtained from subroutines using module B etc., subroutines can have meta information such as arguments and return values.

METHODS

new

Constructor of Sub::Meta.

use Sub::Meta;
use Types::Standard -types;

# sub Greeting::hello(Str) -> Str
Sub::Meta->new(
    fullname    => 'Greeting::hello',
    is_constant => 0,
    prototype   => '$',
    attribute   => ['method'],
    is_method   => 1,
    parameters  => { args => [{ type => Str }]},
    returns     => Str,
);

Others are as follows:

# sub add(Int, Int) -> Int
Sub::Meta->new(
    subname => 'add',
    args    => [Int, Int],
    returns => Int,
);

# method hello(Str) -> Str 
Sub::Meta->new(
    subname   => 'hello',
    args      => [{ message => Str }],
    is_method => 1,
    returns   => Str,
);

# sub twice(@numbers) -> ArrayRef[Int]
Sub::Meta->new(
    subname   => 'twice',
    args      => [],
    slurpy    => { name => '@numbers' },
    returns   => ArrayRef[Int],
);

# Named parameters:
# sub foo(Str :a) -> Str
Sub::Meta->new(
    subname   => 'foo',
    args      => { a => Str },
    returns   => Str,
);

# is equivalent to
Sub::Meta->new(
    subname   => 'foo',
    args      => [{ name => 'a', isa => Str, named => 1 }],
    returns   => Str,
);

Another way to create a Sub::Meta is to use Sub::Meta::Creator:

use Sub::Meta::Creator;
use Sub::Meta::Finder::FunctionParameters;

my $creator = Sub::Meta::Creator->new(
    finders => [ \&Sub::Meta::Finder::FunctionParameters::find_materials ],
);

use Function::Parameters;
use Types::Standard -types;

method hello(Str $msg) { }
my $meta = $creator->create(\&hello);
# =>
# Sub::Meta
#   args [
#       [0] Sub::Meta::Param->new(name => '$msg', type => Str)
#   ],
#   invocant   Sub::Meta::Param->(name => '$self', invocant => 1),
#   nshift     1,
#   slurpy     !!0

ACCESSORS

sub

A subroutine reference.

set_sub

Setter for subroutine reference.

sub hello { ... }
$meta->set_sub(\&hello);
$meta->sub # => \&hello

subname

A subroutine name, e.g. hello

set_subname($subname)

Setter for subroutine name.

$meta->subname; # hello
$meta->set_subname('world');
$meta->subname; # world
Sub::Util::subname($meta->sub); # hello (NOT apply to sub)

apply_subname($subname)

Sets subroutine name and apply to the subroutine reference.

$meta->subname; # hello
$meta->apply_subname('world');
$meta->subname; # world
Sub::Util::subname($meta->sub); # world

fullname

A subroutine full name, e.g. main::hello

set_fullname($fullname)

Setter for subroutine full name.

stashname

A subroutine stash name, e.g. main

set_stashname($stashname)

Setter for subroutine stash name.

subinfo

A subroutine information, e.g. ['main', 'hello']

set_subinfo([$stashname, $subname])

Setter for subroutine information.

file

A filename where subroutine is defined, e.g. path/to/main.pl.

set_file($filepath)

Setter for file.

line

A line where the definition of subroutine started, e.g. 5

set_line($line)

Setter for line.

is_constant

A boolean value indicating whether the subroutine is a constant or not.

set_is_constant($bool)

Setter for is_constant.

prototype

A prototype of subroutine reference, e.g. $@

set_prototype($prototype)

Setter for prototype.

apply_prototype($prototype)

Sets subroutine prototype and apply to the subroutine reference.

attribute

A attribute of subroutine reference, e.g. undef, ['method']

set_attribute($attribute)

Setter for attribute.

apply_attribute(@attribute)

Sets subroutine attributes and apply to the subroutine reference.

apply_meta($other_meta)

Apply subroutine subname, prototype and attributes of $other_meta.

is_method

A boolean value indicating whether the subroutine is a method or not.

set_is_method($bool)

Setter for is_method.

parameters

Parameters object of Sub::Meta::Parameters.

set_parameters($parameters)

Sets the parameters object of Sub::Meta::Parameters.

my $meta = Sub::Meta->new;
$meta->set_parameters(args => ['Str']);
$meta->parameters; # => Sub::Meta::Parameters->new(args => ['Str']);

# or
$meta->set_parameters(Sub::Meta::Parameters->new(args => ['Str']));

# alias
$meta->set_args(['Str']);

args

The alias of parameters.args.

set_args($args)

The alias of parameters.set_args.

all_args

The alias of parameters.all_args.

nshift

The alias of parameters.nshift.

set_nshift($nshift)

The alias of parameters.set_nshift.

invocant

The alias of parameters.invocant.

invocants

The alias of parameters.invocants.

set_invocant($invocant)

The alias of parameters.set_invocant.

slurpy

The alias of parameters.slurpy.

set_slurpy($slurpy)

The alias of parameters.set_slurpy.

returns

Returns object of Sub::Meta::Returns.

set_returns($returns)

Sets the returns object of Sub::Meta::Returns or any object.

my $meta = Sub::Meta->new;
$meta->set_returns({ type => 'Type'});
$meta->returns; # => Sub::Meta::Returns->new({type => 'Type'});

# or
$meta->set_returns(Sub::Meta::Returns->new(type => 'Foo'));
$meta->set_returns(MyReturns->new)

METHODS

is_same_interface($other_meta)

A boolean value indicating whether the subroutine's interface is same or not. Specifically, check whether subname, is_method, parameters and returns are equal.

is_same_interface_inlined($other_meta_inlined)

Returns inlined is_same_interface string:

use Sub::Meta;
my $meta = Sub::Meta->new(subname => 'hello');
my $inline = $meta->is_same_interface_inlined('$_[0]');
# $inline looks like this:
#    Scalar::Util::blessed($_[0]) && $_[0]->isa('Sub::Meta')
#    && defined $_[0]->subname && 'hello' eq $_[0]->subname
#    && !$_[0]->is_method
#    && !$_[0]->parameters
#    && !$_[0]->returns
my $check = eval "sub { $inline }";
$check->(Sub::Meta->new(subname => 'hello')); # => OK
$check->(Sub::Meta->new(subname => 'world')); # => NG

display

Returns the display of Sub::Meta:

use Sub::Meta;
use Types::Standard qw(Str);
my $meta = Sub::Meta->new(
    subname => 'hello',
    is_method => 1,
    args => [Str],
    returns => Str,
);
$meta->display;  # 'method hello(Str) => Str'

OTHERS

parameters_class

Returns class name of parameters. default: Sub::Meta::Parameters Please override for customization.

returns_class

Returns class name of returns. default: Sub::Meta::Returns Please override for customization.

NOTE

setter

You can set meta information of subroutine. set_xxx sets xxx and does not affect subroutine reference. On the other hands, apply_xxx sets xxx and apply xxx to subroutine reference.

Setter methods of Sub::Meta returns meta object. So you can chain setting:

$meta->set_subname('foo')
     ->set_stashname('Some')

Pure-Perl version

By default Sub::Meta tries to load an XS implementation for speed. If that fails, or if the environment variable PERL_SUB_META_PP is defined to a true value, it will fall back to a pure perl implementation.

SEE ALSO

Sub::Identify, Sub::Util, Sub::Info, Function::Paramters::Info, Function::Return::Info

LICENSE

Copyright (C) kfly8.

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

AUTHOR

kfly8 <kfly@cpan.org>