From: Robert Klemme <shortcutter@...>
Date: 2008-02-05T03:29:56+09:00
Subject: Re: convert array to array-of-arrays?

On 04.02.2008 19:22, Robert Klemme wrote:
> On 04.02.2008 17:32, Phlip wrote:
>> Robert Klemme wrote:
>>
>>> irb(main):001:0> [1, 2, 3, 4].to_enum(:each_slice, 2).to_a
>>
>> Thanks! Now, for those of us mired in the doldrums of Ruby 1.8.x, how 
>> to write to_enum in Ruby? I found each_slice, and I know C and ruby.h, 
>> but my Ruby internals are rusty...

PS: In case you wondered: it's pretty easy:

$ irb
irb(main):001:0> EnumProxy = Struct.new :obj, :args do
irb(main):002:1* include Enumerable
irb(main):003:1> def each(&b)
irb(main):004:2> obj.send(*args,&b)
irb(main):005:2> self
irb(main):006:2> end
irb(main):007:1> end
=> EnumProxy
irb(main):008:0> class Object
irb(main):009:1> def to_enum(*a)
irb(main):010:2> EnumProxy.new self, a
irb(main):011:2> end
irb(main):012:1> end
=> nil
irb(main):013:0> %w{foo bar}.to_enum(:each_with_index).each {|*a| p a}
["foo", 0]
["bar", 1]
=> #<struct EnumProxy obj=["foo", "bar"], args=[:each_with_index]>
irb(main):014:0> %w{foo bar}.to_enum(:each_with_index).find {|a,b| b==1}
=> ["bar", 1]

Kind regards

	robert