From: Michael McDaniel <ruby@...>
Date: 2002-04-13T13:38:58+09:00
Subject: RE: not vs !, and vs &&

james@rubyxml.com wrote:

>>
>> > puts true and (! true)   # prints true
>> > puts true &&  (! true)   # prints false
>>
>> very simple. the and has a very low precedence. there are just 3 levels,
>> iirc, and this is the lowest one.
>> so, the first one is equal to
>>
>> puts(true) && (! true)
>>
>> while the second one would be
>>
>> puts(true && (! true))
> 
> Ah so.  Thank you.  I'm still unclear about
>   puts( !true )
> and
>   puts( not true )
> 
> The latter gives a parse/syntax error on Win2K, for 1.6.5 and  1.7.2 (my
> msvc build), and 1.6.7 and 1.7.2 on redhat 6.something.  Is this a known
> bug?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
irb(main):127:0* `ruby --version`
"ruby 1.7.2 (2002-02-22) [i686-linux]\n"
irb(main):128:0> puts ( ! true )
false
nil
irb(main):129:0> puts ( not true )
false
nil
irb(main):130:0>

on SuSE release 7.3

~mm


> 
> On a related note, are there times when the boolean methods of TrueClass
> and FalseClass are prefereably to the general boolean operators?
> 
> 
> 
> Thanks,
> 
> 
> James
> 
>>
>> regards,
>>
>> nick
>>