From: "Jörg Abelshauser" <joerg.abelshauser@...>
Date: 2007-01-05T18:53:09+09:00
Subject: Re: puts returns nil?

Arfon Smith wrote:
> Hi, I'm sorry to be asking such a daft question but I need a concept
> explaining....
> 
> 
> I'm working through the excellent Chris Pine book 'Learn to program' and
> I don't get one of the examples he gives.  In particular I don't follow
> the following example:
> 
> 
> def say_moo number_of_moos
>   puts 'mooooooo...' * number_of_moos
>   'yellow submarine'
> end
> 
> x = say_moo 3
> puts x.capitalize + ', dude...'
> puts x + '.'
> 
> Now the output from this is:
> 
> mooooooo...mooooooo...mooooooo
> Yellow submarine, dude...
> yellow submarine
> 
> -------------
> 
> OK, so here's the problem, I _don't_ get why it doesn't return the
> following:
> 
> 
> mooooooo...mooooooo...mooooooo
> Yellow submarine, dude...
> mooooooo...mooooooo...mooooooo
> yellow submarine
> 
> -------------
> 
> Why do we get one set of 'moos' but not a second?
> 
> Sorry for such a newbiee question.
> 
> Cheers
> 
> arfon

Hi Arfon
in every ruby-function, the last statement (here 'yellow submarine') is 
the return-value of this function, nothing else !
Further yes, puts returns nil.
    puts(obj, ...)    => nil
You can see the declaration of all ruby-functions in the "fxri", 
installed with your ruby-interpreter. It's very helpful to work with it.
3. If you intention was to append the 'yellow submarine' to the puts 1 
line above, you need an '+' to do this:

   puts 'mooooooo...' * 3 +  'yellow submarine'
   mooooooo...mooooooo...mooooooo...yellow submarine

best regards Jörg


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