If !in is inconsistent because of bool/pointer, then so is !

[Rainer Deyke]

downs wrote:
> This is NOT a reason against !in. In fact, this so-called
> "inconsistency" is already present in the language. If we remember,
> !pointer already transforms it into a boolean, so it would actually
> be more consistent if !in changed the return type to bool.

I agree.  'a != b' is short for '!(a == b)'.  'a !is b' is short for
'!(a in b)'.  For consistency, 'a !in b ' should be short for
'!(a in b)'.  I'd even go so far as to say that 'a !+ b' should be short
for '!(a + b)', although I can't think of a use for the '!+' operator.

a !<op> b == !(a <op> b): simple, consistent pattern.
a !<op> b == !(a <op> b), but only for <op> in some limited set that
doesn't include all operators with which you might want to use the
pattern: less consistent; requires memorization.


-- 
Rainer Deyke - rainerd at eldwood.com