From: Neutek <caldridge@...>
Date: 2007-01-18T01:50:10+09:00
Subject: Re: Passing math method to another method?

Wow. Thanks for the input guys.

Robert, I was actually reading the summation wiki and they had a few
code examples in C++/Java.. I thought I'd goof a bit and write
something out in ruby. Of course, I hit the roadblock when trying to
pass math operators(or methods rather) to a method...


I got this far ;-)

def sigma(floor, to_do, cap)

end
puts sigma(4, ^2, 20)

I will fiddle with your suggestions and continue with my sigma :-)

Thanks again for all your help


Robert Klemme wrote:
> On 17.01.2007 15:06, Neutek wrote:
> > I'm trying to figure out how to pass methods such as:
> > +, -, **, ^
> > to a method and evaluate.
> >
> > For example,
> >
> > def test(a, b, to_do)
> >    return a.send(to_do(b))
> > end
> >
> >
> > puts test(1, 2, "+") #should return 3
> > puts test(3, 3, "^") #should return 0
> > puts test(3, 3, "**") #should return 27
> >
> > any help would be appreciated.
>
> Several ways to do it
>
> irb(main):001:0> def test(a,b,op) a.send(op,b) end
> => nil
> irb(main):002:0> test 1,2,:"+"
> => 3
> irb(main):003:0> def test(a,b,op) a.send(op.to_sym,b) end
> => nil
> irb(main):004:0> test 1,2,"+"
> => 3
> irb(main):005:0> def test(a,b,op) op[a,b] end
> => nil
> irb(main):006:0> test 1,2,lambda {|x,y| x+y}
> => 3
>
> The last sample shows the more functional approach.
> 
> What are you trying to achieve?
> 
> Kind regards
> 
> 	robert