From: Rodrigo Rosenfeld Rosas <redmine@...>
Date: 2010-12-20T08:13:36+09:00
Subject: [ruby-core:33774] [Ruby 1.9-Feature#4172][Open] Named arguments/parameters support

Feature #4172: Named arguments/parameters support
http://redmine.ruby-lang.org/issues/show/4172

Author: Rodrigo Rosenfeld Rosas
Status: Open, Priority: Low
Assigned to: Yukihiro Matsumoto, Category: core, Target version: 2.0

It is usual in the Ruby community to use the idiom

def method(options={})
  param1, param2 = options.values_at(:param1, :param2) # or {param1: 'default1', param2: 2}.collect{|k, v| options[k] || v }
  ...
end

instead of

def method(param1, param2)
  ...
end

Perl 6 supports named arguments (or parameters) out-of-the-box. Suppose the following method (not valid Ruby actually):

def tag(tag_name, :content(''), :attributes({}), :closing_tag(true))
  ...
end

It would be great if this could be called as

hr = tag('hr', closing_tag -> false, attributes -> {style: 'color: blue'})

It think it should be even possible to call it like

tag(tag_name: 'div', content: 'Ruby is getting even more awesome with this feature!')

I think it is much more legible than 

tag('hr', '', {}, false)

or than using an 'options' hash parameter.

Is there any reasons why Ruby doesn't support named parameters as part of the syntax?


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