Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!uwm.edu!lll-winken!ncis.tis.llnl.gov!helios.ee.lbl.gov!pasteur!ICSI.Berkeley.EDU!krste
From: krste@ICSI.Berkeley.EDU ( Krste Asanovic)
Newsgroups: comp.std.c++
Subject: case()
Keywords: case statement
Message-ID: <26842@pasteur.Berkeley.EDU>
Date: 8 Aug 90 08:59:17 GMT
Sender: news@pasteur.Berkeley.EDU
Reply-To: krste@ICSI.Berkeley.EDU ( Krste Asanovic)
Organization: International Computer Science Institute, Berkeley, CA
Lines: 22
X-Local-Date: 8 Aug 90 01:59:17 PDT

The C/C++ switch statement is very limited as it only allows integer
expressions. I'd like to suggest a more general case statement.
The syntax would be,

    case (exp) {
        case val1 : s1;
        case val2 : s2;
        default : sOther;
    }

This uses the already reserved keyword case, followed by a
parenthesised expression, to introduce the construct. The standard
switch case and default labels would be used as before. The limitation
that case label expressions are compile-time constants would be
removed (although optimizing compilers could check for this case). The
limitation that case labels be unique would be removed (can't check
this at run time), but the order in which case expressions were tested
would be undefined. Comparisions would use the appropriate ==
operator, in the above example the tests would be

if (exp.operator==(val1)) ..s1...   \ in undefined order.
if (exp.operator==(val2)) ..s2...   /