From: Nathan Weizenbaum <nex342@...>
Date: 2008-05-01T12:46:07+09:00
Subject: Re: lambda, ->, haskell, and so on

I agree, I prefer this syntax. Although I'd prefer being consistent with 
the Haskell convention (and maybe other languages with similar syntax) 
of discouraging a space between the backslash and the first variable name.

Dave Thomas wrote:
> This is one of those e-mails that I know from the start to be futile, 
> but...
>
> For a while now, the
>
>      -> (params) { block }
>
> syntax in Ruby 1.9 has bothered me, but I've never been sure why. 
> Today, while playing with pure, it struck me. The '->' sequence is in 
> an unexpected place. Having played with some functional languages, I'm 
> used to lambdas being written
>
>   \ params -> block
>
> That is, the lambda is introduced with a \ (because, presumably, it 
> looks a bit like ��). The -> sequence separates the parameters from the 
> block. This had become ingrained into be, in the same way that the 
> equals sign in an assignment
>
>   a = expression
>
> goes between the lvalue and the rvalue.
>
> So, when I come to Ruby 1.9, suddenly there's some dissonance between 
> what I was used to and what I now have to type. The -> comes before 
> the parameters, not after. It's as if I had to write assignments
>
>   = a expression
>
> So, here's the futile part... :)
>
> Is it too late for Ruby 1.9 to support lambdas that look like
>
>   \ p1, p1 -> { block }
>
> I honestly feel this would be more natural, and more in line with the 
> prevailing idioms. I suspect it's parsable if you make the simplifying 
> assumption that line continuations must only have whitespace after them.
>
>
>
> Dave
>