From: dblack@...
Date: 2007-06-26T06:16:51+09:00
Subject: Re: .include?/.within? and English-thinking brains

HI --

On Tue, 26 Jun 2007, Michael Judge wrote:

> In English, it's clearer to ask, "Is Maggie one of the guests?" -- rather 
> than the awkward, "Does the guests include Maggie?"

Well, you're stacking the deck a bit to make it sound awkward ("Does
the guests") :-)  Anyway, we have both; it all depends what you're
trying to say.

> So why in Ruby, do we write, "list.include? scalar" -- when we often mean, 
> "scalar.within? list" ?!

Because Ruby isn't English; we use both in English anyway; and Ruby
doesn't have #within? :-)

> The solution:
>
> module Comparable
>   def within?(list)
>     list.include? self
>   end
> end

There's been discussion of this in the past; have a look for #in?
proposed by Hal a while back.


David

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