Path: utzoo!attcan!uunet!mcvax!kth!sunic!enea!sommar
From: sommar@enea.se (Erland Sommarskog)
Newsgroups: comp.lang.misc
Subject: Re: What I'd really like to see in an if-statement...
Message-ID: <178@enea.se>
Date: 11 Aug 89 23:29:15 GMT
Organization: Enea Data AB, Sweden
Lines: 25

I think John Lacey (lacey@tcgould.tn.cornell.edu) said this:
>The parse would be more difficult.  The problems aren't analogous.  The
>dangling-else problem is one of ambiguity.  Parsing a general relational
>expression is difficult because the same string will be used for multiple
>tokens.  For example, in (a < x < b), x has to be associated separately
>to its left and right.

I have to object here. Way back at the university I took a compiler
course. In the tiny language I made for my assignment I defined the 
grammar relational expression something like:
   rel_exp ::= exp (rel_op exp)*
()* meaning 1 or more times easy. Trivial, isn't it? The semantic
interpretation was AND. I.e. 0 < x < 10 was interpreted as (0 < x)
AND (x < 10), which seems as the natural interpretation for the
case you would like to use it for. A thing like
    a = b <= z > y < b
wouldn't something to recommend but the langauge dealt with it the same
way.

Actually I have always been surprised that no language I have dealt
have had this feature since it is so easy to implement. Am I overlook-
ing something?
-- 
Erland Sommarskog - ENEA Data, Stockholm - sommar@enea.se
"Hey poor, you don't have to be Jesus!" - Front 242