From: Robert Feldt <feldt@...>
Date: 2000-09-22T19:10:02+09:00
Subject: [ruby-talk:5063] Default values for named formal parameters


Hi,

We have some sort of named formal parameters, ie you can do

def m(params)
  params['p1'] + params['2']
end

m('p1' => "Hello ", 'p2' => "world!") # -> "Hello world!"

but is there a nice way to have default values for the named parameters?
Ie. I would like

def m(params = {'p1'=>"Hello ", 'p2'=>" world!"})
  params['p1'] + params['p2']
end

m('p2' => "Matz!") # -> "Hello Matz!"

One way you can do it today is with

def m(params)
  params = {'p1'=>"Hello",'p2'=>" world!"}.update(params)
  params['p1'] + params['p2']
end

but if they should really be named formal parameters I guess you should be
able to specify default values with a simpler syntax. Or what do you
think? How do you do it yourself when you classes with lots of options? I
made a small module for this once but I'm thinking on extending it...

Regards,

Robert