From: Alex Fenton <alex@...>
Date: 2006-02-09T03:18:21+09:00
Subject: Re: boolean annoyance

Claudio Jeker wrote:
> Hello,
> 
> there is one thing in ruby that annoys me most (at least for now).
> 
> if 0
> 	puts "true"
> end

class Person
	def number_of_children()
		@children.length
	end

	def has_children?()
		@children.length > 0
	end
end

In this context, like most others from a high-level language perspective, 0 is a valid meaningful value. If you *don't know* how many children a Person's got, return nil. If you *know* a Person hasn't got any return 0. Make a boolean-esque method if you want boolean values. 

As said in other replies and in the innumerable previous threads on this topic, 0's falsity is an implementation oddity of *some* languages. 

It used to create subtle bugs in my Perl code more often than it was a useful shortcut. Understanding why you need 'if ($value)' sometimes and 'if (defined $value)' other times is much more complicated than Ruby's solution.

alex