From: mental@...
Date: 2005-12-16T07:44:56+09:00
Subject: Re: Assigning a block to a variable in Ruby

Quoting ajmayo@my-deja.com:

> I am new to Ruby and curious as to how you emulate the following
> Javascript snippet
> (example in Windows, hence the call to Echo)
>
> var a = function(p) {WScript.Echo(p)}

Ruby:

 a = lambda { |p| WScript.Echo(p) }

(assuming Ruby had an appropriate WScript.Echo)

You'd need to call that like:

 a.call("something")

instead of

 a("something")

though.

> It is also unclear, how, then, I pass down a block as an argument
> and then in turn pass it again to a child routine.

If you prefix the last argument in a method definition or call with
&, then it'll be used to pass/receive a block.

 def f(arg, &block)
   g(arg, &block)
 end

 # call it:
 f(1) { ... }

You can employ a lambda (as illustrated above) as a block using this
& notation too.

-mental