From: "Ara.T.Howard" <ahoward@...>
Date: 2004-08-05T23:11:27+09:00
Subject: Re: Macros in Ruby

On Thu, 5 Aug 2004, Paul Brannan wrote:

> 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

perhaps a shorthand:

   lambda{ puts 'lambda' } => Proc:0xb74041a0
   &{ puts 'lambda too' }  => Proc:0xb74041a1

i'm probably missing something, but i don't think the syntax '&{' occurs
anywhere now and '&' is already synomynous with blocks/procs/etc.

-a
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