From: Mark Hubbart <discord@...>
Date: 2004-04-01T01:20:48+09:00
Subject: Re: Syntax: eval( "a = !a) != eval( "a = not a")


On Mar 31, 2004, at 3:12 AM, Jean-Hugues ROBERT wrote:

> For the sake of curiosity, I would still like to know *why* things
> were designed this way. A way that makes "not" rather useless to me
> (besides the rare case where I would want to avoid a redefined !()).
>
> i.e. why is "not" 's precedence lower than assignment's one ???

The "and", "or" and "not" operators all have lower precedence. If you 
need higher precedence, use "&&" "||" and "!". The word-based boolean 
operators are provided as a counterpoint to the higher priority symbol 
ones. The lower precedence allows you to get away with less parenthesis 
in certain situations.

*>> x = 23 == 23 && ! y = 42 == 23     #=> false
*>> [x,y]                              #=> [false, true]
*>> x = 23 == 23 and not y = 42 == 23  #=> false
*>> [x,y]                              #=> [true, true]

--Mark