From: William James <w_a_x_man@...>
Date: 2008-09-29T06:39:15+09:00
Subject: Re: irb: 1 & 1 => 1, not true huh? I thought 1 & 1 => true

On Sep 28, 4:19 pm, Peter Alvin <f...@awebabove.com> wrote:
> In irb I did:
>
> puts 1 & 1
> and get 1
> shouldn't I get true?
>
> Bottom line is this: What is Ruby idiom to test for bit mask?  Is there
> a more simple way to write:
>
> if session[:permissions] & Permissions::SomeMask ==
> Permissions::SomeMask
>   # user has permission to wash clothes, etc.
> end
>
> TIA,

You say thanks when nobody has replied, so
you are thanking nobody.  You should wait
till someone has replied before you thank
him.  Otherwise, he won't even know that you
have read his post; that is very rude and
inconsiderate.

> Pete

# bitwise
254 & 15
    ==>14
# boolean
254 && 15
    ==>15

Only two things are untrue: nil and false.

puts "it's true" if 0
it's true
    ==>nil
puts "it's true" if 254 & 1
it's true
    ==>nil
puts "it's true" if 254 & 1 > 0
    ==>nil