From: Dave Thomas <Dave@...>
Date: 2001-05-07T22:09:25+09:00
Subject: [ruby-talk:14765] Re: skipping arguments

touch freedom <stillflame@go.com> writes:

> now, when calling this method, say i only want to change the value of
> b, while leaving a the same.  how can i do this?

Some future Ruby will support keyword arguments, which means you could
say something like the following (except the syntax is totally
arbitrary: the final syntax will probably look a lot different):

   def addPerson(name, withAge: a=0, withSex: s=FEMALE, withHair: h=UNKNOWN)
      # ...
   end

Then these would be valid calls:

  addPerson('Fred', 23, MALE, BROWN)

  addPerson 'Barney' withSex: MALE  withAge: 20

  addPerson 'Wilma'  withHair: BLONDE


(again, remember the syntax is just made up).


In the meantime, you can almost have your second wish, as Ruby does
support passing in has values as arguments:

  def addPerson(name, attributes)
     # ..
  end

  addPerson 'Fred', 'age' => 23, 'sex' => MALE, 'hair' => BROWN


The last three parameters in this example will be added into a single
hash, which will be received by addPerson in the 'attributes'
parameter.


Regards


Dave