From: Rob Biedenharn <Rob@...>
Date: 2007-07-12T05:39:44+09:00
Subject: Re: question about passing hashes to an action

On Jul 11, 2007, at 3:53 PM, Max Williams wrote:
> It seems to be a common tactic in ruby to pash what looks like a
> key-value pair, in which the key is a symbol, to an action.  For  
> example
> with the rails action 'render', we say
>
> render :text => "Hello world!"  #(from dhh's famous blog tutorial)
>
> Can anyone explain to me what's happening here, ie what's being passed
> in?  Is it the equivalent of having a (say) java method that takes a
> string and saying
> render("Hello world!")?
>
> I've been trying to experiment with my own classes with this  
> tactic, but
> i'm new to ruby and can't get an example of the above working.

The trailing set of key => value pairs are turned into a hash passed  
as the final argument to a method.  The fully punctuated version of  
that is:

render({:text => "Hello world!"})

You'll often see methods defined as:

def my_method(arg1, arg2, options={})

when there is an optional set of options that can be passed in as a  
hash.

-Rob


Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com