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An "is also" trait that gives one method several names — aliases for a friendlier API, or for the protocol hooks Raku itself looks up, with no forwarder methods to write.

Version

0.0.10 zef:lizmat

Depends

nothing outside the core

License

Artistic-2.0

Its own test suite

1 file, green

Checked

2026-08-28 against Raku++ 3.20.1 and Rakudo 2026.08

Where it lives

raku.land · source

Install it #

$ rakupp install Method::Also

zef install Method::Also writes the same store; either installer leaves the module usable by both engines.

What it is for #

Sometimes one method honestly has two names. You renamed add to push and owe your users a release of overlap; your queue class wants to read naturally to people arriving from either .enqueue or .push habits; or you want the same body to serve both your public name and a protocol name Raku looks up by convention. Without this module each alias is a forwarder method you write and keep in sync. With it, the alias is part of the declaration:

use Method::Also;

class Queue {
    has @!items;
    method push($x) is also<enqueue add> { @!items.push($x); self }
    method shift() is also<dequeue> { @!items.shift }
    method elems() is also<Numeric> { @!items.elems }
}

my $q = Queue.new;
$q.enqueue('a');
$q.add('b');
$q.push('c');
say $q.dequeue;
say $q.elems;
say $q + 0;

a
2
2

Every name in the angle brackets is a real method on the class — same body, same object, shown by the last line: aliasing elems to Numeric is all it takes for a Queue to numify, because + 0 makes Raku call .Numeric. That trick — pointing a protocol name at a method you already have — is the quiet superpower here: Str, Bool, Numeric, gist are all just method names something else agrees to call.

It composes with multis and coercions #

The trait goes per candidate, so one spelling of a multi can carry the alias while its siblings stay single-named — and aliasing gist to Str makes stringification and say agree with one body:

use Method::Also;

class Temperature {
    has $.celsius;
    multi method in(Str $unit where 'C') is also<as> { $!celsius }
    multi method in(Str $unit where 'F') { $!celsius * 9/5 + 32 }
    method gist() is also<Str> { "{$!celsius}°C" }
}

my $t = Temperature.new(:celsius(21));
say $t.in('F');
say $t.as('C');
say ~$t;

69.8
21
21°C

Note what is also on a multi candidate means: as is an alias for the whole dispatch under that name — but only candidates declared with the trait travel; here .as('F') would not dispatch, which is the behaviour you asked for by aliasing one candidate.

Keep the trait on class methods. Aliasing methods in roles is where the module's own documentation waves a flag, and this page's testing agrees — see below.

Where the two engines differ #

Aliases declared in a role with several names behave differently: composing the role above as written works fully under Raku++, while under Rakudo some of the alias names fail to appear on the composing class (.count is also<elems size length> in a role yielded a working elems and a missing size under Rakudo 2026.08). This is upstream-acknowledged territory rather than a Raku++ gap — the module registers aliases through compiler internals that treat role specialization differently — but the portable rule is simple: alias in classes, and everything on this page holds on both engines.

What was run to put this page here #

1. Parse — every file of the distribution is parsed by Raku++ itself.
2. Install — rakupp install Method::Also; it depends on nothing outside the core.
3. Test — the distribution's own suite: 1 file, green.
4. Run — every example on this page, twice under each engine, as the site is built.

This module is worth a pause: it works by adding methods through the metaobject protocol at composition time, so its suite going green is a statement about Raku++'s MOP — add_method on a ClassHOW, trait handlers running at compile time, and is hidden-from-backtrace all behaving — not about string handling in some also helper. Twenty-one distributions depend on it, lizmat's own among them.