From: "David A. Black" <dblack@...>
Date: 2008-05-09T01:04:29+09:00
Subject: Re: lambda, ->, haskell, and so on

Hi --

On Fri, 9 May 2008, ara.t.howard wrote:

>
> On May 8, 2008, at 9:35 AM, David A. Black wrote:
>> The arrow really looks weird there, since it's not pointing to
>> anything but looks all the more like it is (since there's something on
>> the left).
>
> i'm confused: in what way is this 'not pointing to anything'
>
>
>
> irb(main):013:0> def pointed(opts) opts[:before].call end
> => nil
>
>
> irb(main):014:0> pointed before: -> { p 42 }
> 42
> => 42

Because if the arrow means "I'm pointing", then the {} should be a
hash. Of course one can describe that one case as "symbol: plus arrow
pointing to curly braces which mean a lambda in this context", but the
problem is that the presence of an arrow *in that one case* is just
serendipitous. It still leaves you with:

   my_method(str: "hello")

where suddenly the logic of "pointing from the symbol to the object"
has vanished.

Also, I believe -> was chosen because it's supposed to look like
a sideways lambda, not because it looks like an arrow. Unfortunately
it looks like an arrow.

Again, the oddness of the special-case non-arrow-arrow in argument
lists wouldn't be a deal-breaker for me if I had no other problem with
the ->(){} syntax, but I'm not a fan of it in general.


David

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