From: matz@... (Yukihiro Matsumoto)
Date: 2002-10-30T15:29:40+09:00
Subject: Re: "multiple assignment in conditional"

Hi,

In message ""multiple assignment in conditional""
    on 02/10/30, "Gavin Sinclair" <gsinclair@soyabean.com.au> writes:

|Given this:
|
|  def foo
|    [4,5]
|  end
|
|Both of the following expressions give me a SyntaxError: "multiple assignment
|in conditional" (this is Ruby 1.6.5 on Cygwin):
|
|  a, b = foo and puts a
|  (a, b = foo) and puts a
|
|I must say that I'm perplexed by this.  "Ruby in a Nutshell" (p. 18) tells me
|that "and" has lower precedence than "=".  Of course, the parentheses make my
|intention clear anyway, and I still get the error.  So I just don't understand.

The resulting value of multiple assignment may not be what you expect,
due to value-array conversion.

  % ruby1.6 -e 'p ((a,b = nil))'
  [nil]
  % ruby1.7 -e 'p ((a,b = nil))'
  []

That's why I warned you.

							matz.