From: Charles Oliver Nutter <headius@...>
Date: 2010-01-01T09:47:53+09:00
Subject: Re: Why can't I use "or" here?

On Wed, Dec 30, 2009 at 11:32 PM, Albert Schlef <albertschlef@gmail.com> wrote:
> Well. it turns out there aren't that many ways in ruby.
>
> I originally tried to do the following:
>
>  some_func(ARGV[0] or raise "You must provide an argument")

First off, I'd say that this is probably confusing form to use. If I
ever saw this in code I'd write it differently.

> I wish it worked. But it doesn't. So I changed it to:
>
>  some_func(ARGV[0] || raise "You must provide an argument")
>
> It still didn't work. So finally I did:
>
>  some_func(ARGV[0] || (raise "You must provide an argument"))
>
> It works. But, I must say, it isn't as beautiful as my original plan. It
> doesn't read as English.

This isn't too bad, for what you want:

some_func ARGV[0] || raise('you must provide an argument')

or:

some_func(ARGV[0] || raise('you must provide an argument')

And if I were to write this, I'd probably choose one of these variants:

ARGV[0] ? some_func(ARGV[0]) : raise 'you must provide an argument'

or

raise 'you must provide an argument' unless ARGV[0]
some_func(ARGV[0])

- Charlie