From: Hugh Sasse Staff Elec Eng <hgs@...>
Date: 2001-06-19T01:19:08+09:00
Subject: [ruby-talk:16591] RCR: Enumerable: every() and none()

I've been off the list for a while but I'm dipping back in to suggest:

Enumerable should have functions every and none to complement find_all
and reject.  I think it is likely that people will want to know if all
the things in the enumObj match or all don't match the conditions
specified by block. So:

def every(&block)
    find_all(&block) == to_a()
end

def none(&block)
    reject(&block) == to_a()
end

I have come up against this  when trying to define a fuzzy set
which might be constructed by defining the corners of a trapezoid,
or might be constructed by passing a whole collection of trapezoids
to the constructor.  I want to be sure when

    def initialize(*params)
        [...]
    end

that EVERY *params is numeric, or that EVERY *params is a trapezoid....
I submit that this is generalized enough and useful enough to merit
inclusion in ruby, hence my proposing this RCR.  There may be a more efficient
way to implement this than with the above code, so that is intended only
as a description of functionality.

I hope this is a useful suggestion.
	Hugh
	hgs@dmu.ac.uk