From: Caleb Clausen <caleb@...>
Date: 2009-09-22T23:57:25+09:00
Subject: [ruby-core:25712] Re: [Bug #2131](Rejected) f(not x) => syntax error

Nobuyoshi Nakada wrote:
> `not' expression is a statement, and a statement can't be an argument without parentheses.

I've been aware for a long time that 'not', 'and', and 'or' are 
disallowed directly inside method arguments, but I've never understood 
the justification. Can someone please explain to me _why_ 'not' should 
be treated differently than '!' in this context?