From: "Iván Vega Rivera" <ivanvega@...>
Date: 2006-03-08T11:25:07+09:00
Subject: Re: Passing the same argument(s) to several methods at once

Oh I understand now!

Thanks!

Ivan V.

On 3/7/06, Wilson Bilkovich <wilsonb@gmail.com> wrote:
> On 3/7/06, Iv�n Vega Rivera <ivanvega@gmail.com> wrote:
> > Thanks but could you explain me a little bit more how that works? Ruby
> > says 'block' is undefined. So I'm missing something.
> >
> > The problem is I don't quite understand how that code works :-)
> >
> > Ivan V.
> >
> > On 3/7/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
> > >
> > > the general case is:
> > >
> > >   %w( function_a function_b ).each{|m| receiver.send(m, *args, &block)}
> > >
> > > works for any number of args, any receiver, and any block or lack of.
> > >
>
> %w(function_a function_b) creates an Array that looks like this:
> ['function_a', 'function_b']
>
> 'each' is an instance method of Array (via the Enumerable module)
> that, when given a block, 'passes' each entry of the array to the
> block one by one.
> In this case, the block variable is 'm', and so 'm' will be the string
> 'function_a', and then the string 'function_b'.
>
> Let's modify your original example a little to show what object
> 'function_a' and 'function_b' are methods on.
>
> someobject.function_a('something')
> someobject.function_b('something')
>
> ..and let's rename that block variable to make what is going on a
> little clearer:
> %w(function_a function_b).each {|message| someobject.send(message, 'something')}
>
> By 'general case', Ara means that someobject.send(m, *args, &block)
> will handy any kind of method signature that 'm' might happen to have,
> no matter how many parameters it expects.
> Methods can choose to explicitly accepts blocks as parameters in Ruby,
> though it's a little uncommon in typical code.
> 'send' invokes a method by name, which is handy for this kind of thing.
>
>