From: Martin DeMello <martindemello@...>
Date: 2006-11-28T06:55:34+09:00
Subject: Re: simple loops and recursion

On 11/28/06, ishamid <ishamid@colostate.edu> wrote:
>     puts "Sorry, expected #{expected_value} but got #{actual_value}"
[...]

> gives me
>
> ===================
> Sorry, expected 98 but got 98
> ===================
>
> Of course, the problem is that I entered a string not an integer.
>
> The output does not distinguish number from numeral. Is this standard
> or is there something else going on?

When you interpolate an expression in a string, ruby first evaluates
it, then calls to_s on the result. 98.to_s = "98"

Here's an illustrative example - I'll define a class and give it a
to_s method, then create an object of that class and embed it inside a
string:

irb(main):001:0> class MyClass
irb(main):002:1>   def to_s
irb(main):003:2>     "hello world"
irb(main):004:2>   end
irb(main):005:1> end
=> nil
irb(main):006:0> a = MyClass.new
=> hello world
irb(main):007:0> puts "the language that cannot print '#{a}' is not
the true language"
the language that cannot print 'hello world' is not the true language
=> nil

martin