From: "Mehr, Assaph (Assaph)" <assaph@...>
Date: 2004-09-27T14:01:05+09:00
Subject: Re: {newb} Help with ref


<snip code>

> Anyway, I am lost on why i have to create a copy of the string in
> decrypt. I know why my it string gets crushed because encrypt uses it.
> How does one make it use a copy of the varablie instead of pointing to
> the memory location? 

As you seem to already know, all variables are just references to
objects. 
In order to create a copy of a variable you can usually use .dup or
.clone.
See: 
http://www.ruby-doc.org/core/classes/Singleton.html#M001467 and
http://www.ruby-doc.org/core/classes/Object.html#M000909.

Notice however in your programs that the line:
  data= data.upcase
In encrypt actually creates a local variable named data, overshadowing
the parameter data. You can see this in IRB:

irb(main):001:0> def foo(data)
irb(main):002:1>   data = data.upcase
irb(main):003:1> end
=> nil
irb(main):004:0> s = "hello"
=> "hello"
irb(main):005:0> foo s
=> "HELLO"
irb(main):006:0> s
=> "hello"


> also how do you return a value in a function(def)?

You can either use the 'return' statement, or just the last value of the
method.
It is a convention to write in the style:

def foo(arg)
  result = []
  ... # calculations with arg and result
  result
End

thus
 ary = foo(123)
Will give the result of foo in the variable ary.

The 'return' statement is normally used when you need to prematurely
exit the method:

def foo
  ...  #stuff
  if condition
    return false
  end
  ... # more stuff
  result
end

Thus foo will return the contents of 'result' or false.

Notice also the *everything* returns a value, similar to functional
languages. Thus you can write:

def foo
  if condition1
    1
  elsif condition2
    2
  else
    3
  end
End

Or:

def bar
  case condition
    when pattern1	then 1
    when pattern2	then 3
    when pattern3	then 4
  end
end


See the end of the section "Invoking a method" in:
http://phrogz.net/ProgrammingRuby/language.html#invokingamethod


> If you do not want to tell me because you dont think i
> read the chm file, then please tell me where i can read how to do this
> (simple examples would also be great)?

You'll usually find this list much friendlier than just RTFM, even
though reading the ProgrammingRuby book cover to cover is highly
recommended :-)

See if you can rewrite your program better and 

HTH,
Assaph