From: Mike Austin <"mike[nospam]"@...>
Date: 2008-12-02T19:44:32+09:00
Subject: Re: Enumerable#select used to return actual values

Pe�a wrote:
> From: Mike Austin [mailto:"mike[nospam]"@mike-austin.com] 
> .
> # (1..10).select { |a| a * a if a > 5 }
> 
> the difficulty there is that there is no clear separation bw the selection logic and the mapping logic

that's... the idea.

> # Was it ever there, or did I just have a dream about it?  
> # It's easy to implement... just wondering.
> 
> it's easy in 1.9..
> 
> 
>> p (0..10).select_with_map ->(x){x<5}, ->(x){x*x}
> [0, 1, 4, 9, 16]

The new syntax looks like a function got run over by a lambda.  Twice.
I guess it wasn't possible to make them look like lambdas?

> one could also do partitioning if 3rd block is provided (wc catches the else portion)
> 
>> p (0..10).select_with_map ->(x){x<5}, ->(x){x*x}, ->(x){x+x}
> [[0, 1, 4, 9, 16], [10, 12, 14, 16, 18, 20]]
> 
> 
> but still i prefer {|x| x<5} over ->(x){x<5}
> or maybe, ->{|x| x<5} over ->(x){x<5}

I wouldn't mind "&{|x| x < 5}" - shorthand for "&lambda {|x| x < 5}" which you 
can pass to functions that require a block:

(1..10).map &lambda {|n| n * n}

Mike