From: Sy Ali <sy1234@...>
Date: 2006-09-11T02:57:45+09:00
Subject: Re: patching strings together to make a variable

On 9/10/06, Mike Stok <mike@stok.ca> wrote:
> > Previously, I've been duplicating methods and just renaming a single
> > variable.. (just to ensure that method1 works the same as method2) a
> > variation of this would be cleaner I think.
> >
> > My code is still quite hackish, so it's likely that I'll figure things
> > out in some time, and will be able to evolve towards even cleaner
> > code, perhaps dropping this trick.
>
> What are you actually trying to do?  Sometimes stepping back from a
> particular obstacle can give a fresh point of view which sometimes
> leads to "nicer" code.
>
> Mention of duplicating methods and renaming a single variable hints
> strongly there may be more ways to skin this cat.

I was just looking for an alternative to the classic if/then/else.

My original method would do this:

def test1
  puts "#{@something_something}"
end

def test2
  puts "#{@something_something_else}"
end

or maybe I could have done this:

def test(string)
  if string == "something" then
    puts "#{@something_something}"
  elsif string == "something_else" then
    puts "#{@something_something_else}"
  end
end

What if I wanted to expand this a thousand-fold?  I'd have to do this:

def test(string)
  case string
    when "something" : puts "#{@something_something}"
    when "something_else" : puts "#{@something_something_else}"
    # ... repeated many more times
  end
end

But that thousand-line case could be replaced with a one-liner:

def test(string)
  puts "#{instance_variable_get("@#{string + "_something"}")}"
end


I got here because I was looking at my inelegant code and wanted to
know how it could be simplified when faced with greater use.

Thinking in infinites.. yes, it's optimising early, but I wanted to
learn something new.