From: Pit Capitain <pit@...>
Date: 2002-08-04T23:30:40+09:00
Subject: Verbose map (Re: Should this work?)

On 4 Aug 2002, at 22:31, Gavin Sinclair wrote:

> (...)
> Now, I love the "map" method, but sometimes its use is more verbose
> than it could be.  It "would be nice" if one could do the following
> things:
> 
> names = %w(john mary adam jacky)
> names.map { capitalize }          # -> ["John", "Mary", "Adam",
> "Jacky"]
> 
> x, y, z = [], [], []
> [x, y, z].map { $_ << [nil] }     # -> [nil, nil, nil]
> [x, y, z].map { $_ == [nil] }     # -> [true, true, true]
> 
> Obviously there are limits, but I think that there could be a way to
> do this without exposing the language to ambiguity, contradiction,
> slothfulness or confused identity (!)  The "capitalize" example may be
> stretching it a bit far, but surely the other two examples are good?
> 
> What do people think?

What about the following? It's not quite the same, but less verbose 
than map itself:

  module Enumerable
    def mapsend( method, *args )
      map { | target | target.send( method, *args ) }
    end
  end

  names = %w(john mary adam jacky)
  names.mapsend( :capitalize )  # -> ["John", "Mary", "Adam", 
"Jacky"]

  x, y, z = [], [], []
  [x, y, z].mapsend( :<<, nil )  # -> [[nil], [nil], [nil]]
  [x, y, z].mapsend( :==, [nil] )  # -> [true, true, true]

Regards,
Pit