From: Magnus Holm <judofyr@...>
Date: 2010-09-15T14:41:24+09:00
Subject: [ruby-core:32392] Re: Making custom_lambda() work

Technically, it's possible. The parser keeps a list of the local
variables in the scope, so when it encounters "x()" it can simply
check: if local_variables.include?("x") ? "x.call()" : "x()". But as
matz mentioned, this isn't the easiest thing to do in the current
parser.

I'm not sure if this special syntax is a good or bad thing, but I just
thought I mention one way this could be accomplished.

// Magnus Holm



On Wed, Sep 15, 2010 at 05:41, Gary Wright <gwtmp01@mac.com> wrote:
>
> On Sep 14, 2010, at 12:11 PM, Magnus Holm wrote:
>
>> Of course, if you read the proposal again, you'll see that it doesn't
>> even mention the word "lambda". I'm talking about changing the meaning
>> of "foo()" where foo is a local variable. So in this example:
>>
>> a = [1,2,3]
>> s = "Hello World!"
>> h = { :color => :red }
>>
>> a()
>> s()
>> h()
>>
>> That would actually run "a.call()", "s.call()" and "h.call()". There's
>> no special case for lambda.
>
> I think you are still stuck with an ambiguity that can't be resolved
> at parse time. The problem is that 'x()' already has a meaning to the
> parser when x is a local variable. You can't re-write this to
> x.call() at parse time because that would bypass the method call to 'x'.
> The best you could do would be to restart the call as x.call() when 'x'
> isn't found.
>
> I'm still against it because of the special casing, and the complexity
> of interacting with method_missing:
>
> �� �� �� ��search for method 'x' and invoke if found
> �� �� �� ��search for method 'x.call' and invoke if found
> �� �� �� ��search for method_missing and invoke if found
> �� �� �� ��search for 'x.method_missing' and invoke if found
>
> I'm not even sure if that would be the 'correct' order for handling
> method_missing.
>
> I just don't see why #call should have special syntax especially when
> you can already get pretty darn close with #[]:
>
> �� �� �� ��some_proc_like_reference[1,2,3]
>
> Gary Wright
>
>
>
>
>
>