From: Jano Svitok <jan.svitok@...>
Date: 2007-08-08T23:20:15+09:00
Subject: Re: case statement

On 8/8/07, Shai Rosenfeld <shaiguitar@gmail.com> wrote:
> Alex Young wrote:
> > Shai Rosenfeld wrote:
> >> end
> >>
> >> ((i.e, whatever value is included in the array))
> >> ...how do i do this?
> >
> > Does the Array#include? method do what you need?  Perhaps a more
> > fleshed-out example might help?
>
> Array#include is EXACTLY what i need, but syntaxtetically (if u get the
> drift) i'm not sure how to do it:
>
> case [3, 45, 6, 'abc'].inlcude?
> when 1: 'no good'
> when 3: 'good!'
> when 'lolo': 'no good'
> end
>
> (the above doesn't work. it's gives a 'not enough arguments' error. how
> do i do it correctly?)

You could possibly do something like the following, but it's pretty dangerous:

class Object
	 alias_method :old_case_equal, :===

	 def ===(other)
		case other
		when Array:
			other.include? self
		else
			old_case_equal(other)
		end
	 end
end

puts case [3, 45, 6, 'abc']
when 1: 'no good'
when 3: 'good!'
when 'lolo': 'no good'
end

I.e. case calls === on each when condition, so if you define proper
=== that will not break other things, you're done.

when you run

case a
when b: ...
when c: ...
end

ruby will evaulate

b === a, i.e. b.===(a)
c === a, i.e. c.===(a)

J.