From: Le Wang <lewang@?.?.bigfoot.com> (nospam)
Date: 2002-01-01T09:43:40+09:00
Subject: [ruby-talk:29918] Re: && vs. and

On Mon, 31 Dec 2001 12:39:15 GMT, David Alan Black
<dblack@candle.superlink.net> wrote:

>Hello --
>
>On Mon, 31 Dec 2001, Le Wang wrote:
>
>> Hi all,
>>
>> In "Programming Ruby", it was explained that the only difference
>> between '&&' and 'and' is precedence, the same seems to be implied in
>> the 1.4 Reference Manual.
>>
>> <code>
>> true and puts 'test'
>> true && puts 'test'
>> </code>
>>
>> Why doesn't the second statement work?
>
>
>I believe it's parsed as:
>
>  (true && puts) 'test'

That explains it.  I never took precedence that way.

This leads to a design question.  Since '&&' is a keyboard that
performs boolean logic tests, should it not have lower precedence than
all method calls?

On top of this, '&&' is not a valid method name, so why is it parsed
this way?

>
>so the bare string 'test' at the end of the line causes a parse error.
>
>Try:
>
>  true && puts('test')
>
>(Hmmm...  Playing around with this I'm mildly surprised that "true &&
>nil" is nil, rather than false.)
>
>
>David