From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-08-09T00:14:55+09:00
Subject: Re: new block notation (was: Re: ruby-dev summary 26468-26661)

On Mon, 8 Aug 2005, Yukihiro Matsumoto wrote:

> I don't care if they are different object or not.  It's an
> implementation detail we don't talk about yet.
>
> The point is
>
>  (a) we need blocks as they are now.
>  (b) I think we need anonymous functions, which
>     (1) require all argument functionality of method
>     (2) should be terminated by return inside body
>
> For (b-1) I now think we need a new syntax for lambdas, not just
> extend block parameters.  In general, block parameters do not need
> optional arguments, nor keyword arguments.

how about this syntax for anonymous functions:

   function with one param

     {a -> p [a]}

   function with two params

     {a, b -> p [a, b]}

   function with no params (perhaps omit ->)

     {_ -> p 42}

   function with any params - anonymous (perhaps omit ->)

     {* -> p 42}

   function with no params - named

     {*a -> p a}

the details of the parameter lists is not important - perhaps they could
follow exactly the same rules as normal functions, perpahs not.  the idea here
is that the '->' operator could signify a mapping from an input set to an
output set - a function.  the precence of it would allow the parser to reduce
when it was seen, which would never be far from the open '{' so it would not
be too hard to parse i think.

just thought i'd throw that out there...

-a
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