From: Simon Strandgaard <0bz63fz3m1qt3001@...>
Date: 2003-07-22T05:46:35+09:00
Subject: Re: Proposal: Array#to_h, to simplify hash generation

On Tue, 22 Jul 2003 06:00:53 +0900, Brian Candler wrote:

> On Tue, Jul 22, 2003 at 02:24:35AM +0900, Simon Strandgaard wrote:
>> On Tue, 22 Jul 2003 02:57:40 +0900, Brian Candler wrote:
>> 
>> > On Tue, Jul 22, 2003 at 01:43:46AM +0900, Brian Candler wrote:
>> >> The bit I don't like is Hash#<< taking an array of two elements, rather than
>> >> having two arguments
>> > 
>> > I forgot about using Method#arity. New version attached... Brian.
>> > 
>> > class Array    # ditto for Enumerable
>> >   def collect(dest=Array,*args)
>> >     res = dest.new(*args)
>> 
>> Maybe its better to do the #new outside collect ?
> 
> Yes, I worked that out in parallel with you :-) Thinking while walking home,
> the pattern

:-)


> Since not all objects necessarily have a '<<' method then maybe it's worth
> having that as a parameter as well. The attached code lets you do that, or
> guesses at a suitable method if one isn't provided.

Good idea to test for different append methods 


[snip code]


#collect_into / #map_into   is nice.
How about abbreviating the name, so its just:  #into


p [1, "2", 3].into({}) { |i| [i.class, i] }
# {"Fixnum"=>[1, 3], "String"=>["2"]}


Important: Hash#append should not overwrite earlier entries.

--
Simon Strandgaard