From: nobu.nokada@...
Date: 2003-09-03T21:42:46+09:00
Subject: Re: Possible to make compound if statements...

Hi,

At Wed, 3 Sep 2003 21:06:54 +0900,
Joey Gibson wrote:
> ||| History lesson: 'and' and 'or' and 'not' are used in
> ||| languages like BASIC, Algol, and Pascal. && and || and !
> ||| are used in languages like C, C++, and Java. Ruby happens
> ||| to know both forms.
> 
> Also 'and' and 'or' have "extremely low precedence" (according to Ruby in a
> Nutshell) so constructs using them _may_ behave differently than those
> using && and || and my need parentheses to clear up ambiguities. I don't
> have any good examples, but I'm sure someone does.

  foo = false || bar = true	# foo = true, bar = true
  foo = false or bar = true	# foo = false, bar = true

The former is equivalent to

  foo = (false or bar = true)

and the latter is

  (foo = false) || (bar = true)


Also note that 'and' and 'or' have same precedence.

(foo or bar and bas) means ((foo || bar) && bas)
but
(foo || bar && bas) is (foo || (bar && bas))

-- 
Nobu Nakada