From: dblack@...
Date: 2003-01-28T10:11:21+09:00
Subject: Re: Parsing: x = y || raise "error"

Hi --

On Tue, 28 Jan 2003, Daniel Carrera wrote:

> dir = ARGV.shift || raise "Require directory argument"
>
> Is probably getting parsed as:
>
> dir = (ARGV.shift || raise) "Require directory argument"
>
> When you type
>
> dir = ARGV.shift || raise("Require directory argument")
>
> Ruby parses it as
>
> dir = ARGV.shift || (raise("Require directory argument"))

In fact, I believe it's even:

  dir = (ARGV.shift || (raise("Require directory argument")))

meaning, dir is getting assigned to whether ARGV.shift works or not
(the return value of raise).  This may not matter, since [].shift ==
nil and raise returns nil, but still, it's probably good to be aware
of.

> Use 'or' instead of ||, it has lower precedence.

(And solves any weirdness of the above kind :-)


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav