From: Robert Klemme <bob.news@...>
Date: 2006-02-09T18:13:23+09:00
Subject: Re: boolean annoyance

Claudio Jeker wrote:
> On Thu, Feb 09, 2006 at 07:35:08AM +0900, Alexis Reigel wrote:
>> When I started using ruby I had exactly the same problem as you,
>> porting some c code to ruby that was checking some flags. I didn't
>> get to the solution myself, as I never ever thought of 0 being true.
>> But once you see the advantages of it you'll really appreciate that
>> convention.
>> In c you do: (flags & 0x01)
>> In ruby you do: (flags & 0x01 == 0) or (flags & 0x01).nonzero?
>> Or even nicer: flags[0x01]
> 
> Does flags[0x01] work with any kind of mask. I thought that flags[3]
> would return the value of bit 3 and not the value of bit 0 and 1...
> and from the ruby reference Bignum#[] returns the nth bit a 0 or 1
> and so your flags[0x01] would suffer the same way as (flags & 0x01).

You are correct.  It should have read

if flags[0] == 1
....

Kind regards

    robert