From: Martin DeMello <martindemello@...>
Date: 2005-09-16T00:31:34+09:00
Subject: Re: Math: sum and faculty

Robert Klemme <bob.news@gmx.net> wrote:
> 
> To sum up, #sum seems too specialized.  #inject is there and does the job
> quite nicely - and easily.

Actually, something in between would be quite nice in terms of code
aesthetics. I'm thinking of the specialised but very common case of a
binary accumulator and a unary function, thus (calling it 'accumulate'
for want of a better name):

sum = enum.accumulate(0, :+) {|x| f(x)}
collect = enum.accumulate([], :<<) {|x| f(x)}

and if you leave off the block, it simply applies f(x) = x. It avoids
cluttering the block with the accumulator the way inject does.

martin