From: Paul Brannan <pbrannan@...>
Date: 2004-08-05T22:44:55+09:00
Subject: Re: Macros in Ruby

On Thu, Aug 05, 2004 at 12:31:30PM +0900, Jesse Jones wrote:
> In article <161164987028.20040805090540@soyabean.com.au>, Gavin
> Sinclair <gsinclair@soyabean.com.au> wrote:
> 
> > Which do you prefer?
> > 
> >    (1..10).map { |n| n ** 2 }
> > 
> >    (1..10).map( lambda { |n| n ** 2 } )
> 
> I prefer a light-weight syntax for something as commonly used as
> anonymous functions. On the other hand, I still don't know why {|n| n
> ** 2} can't simply create a proc object. 

Remember how the lambda method works: it takes a block parameter and
creates an object out of it.  IMO this is very clean; blocks are the
basic building block and procs and bindings are built on top of them.

As to why we cannot remove the call to the lambda method, consider:
  1. Ruby does have blocks, and
  2. Ruby does not require parens for method calls.

If I write:

  (1..10).map { |n| n ** 2 }

Should this be interpreted as:

  (1..10).map(lambda { |n| n ** 2 })

or as:

  (1..10).map do |n| n ** 2; end

If it were possible to merge blocks and proc objects without
introducting ambiguity and without losing backward compatibility, it
might not be a bad idea.  I do not think this is possible, though.

Paul