From: Tim Pease <tim.pease@...>
Date: 2007-11-04T05:59:22+09:00
Subject: Re: dragons and factorials (keyboard input)

On Nov 3, 2007, at 1:35 PM, Thufir wrote:

> I'm getting keyboard input successfully, but I'm getting a string.  I
> need to convert it to a number.  But ruby is a dynamic language?
> What's happening please?
>

Others have already answered your question, and it appears you  
figured it out or yourself, too.

Ruby does not perform coercion on strings. Perl allows you to do  
this ...

1 + "2"     #=> 3

However, Matz decided to make type coercion the responsibility of the  
programmer and not the programming language. Whenever input is read  
(from a file or the command line) it is returned as a string. It is  
up to your program to convert that string into an Integer, a Float,  
and imaginary number, etc. In ruby you would need to write ...

1 + Integer("2")    #=> 3
1 + "2".to_i    #=> 3
1 + "2"     #=> raises an error

You can write your own coerce method for the string class, if you are  
so inclined, in order to make ruby strings behave like Perl strings.

class String
   def coerce( other )
     case other
     when Integer: [other, Integer(self)]
     when Float: [other, Float(self)]
     else raise TypeError, "can't coerce into '#{other.class.name}'" end
   end
end

WIth a coerce method defined for String, you can now write the  
following in Ruby ...

1 + "2"    #=> 3

Blessings,
TwP