Path: utzoo!attcan!uunet!husc6!uwvax!tank!shamash!nis!sialis!orbit!pnet51!shawn
From: shawn@pnet51.cts.com (Shawn Stanley)
Newsgroups: comp.lang.c++
Subject: Re: Improved switch statement
Message-ID: <437@orbit.UUCP>
Date: 27 Dec 88 18:05:04 GMT
Sender: root@orbit.UUCP
Organization: People-Net [pnet51], Minneapolis, MN.
Lines: 30

nevin1@ihlpb.ATT.COM (Liber) writes:
>In article <574@redsox.UUCP> campbell@redsox.UUCP (Larry Campbell) writes:
>
>|I think it would be eminently sensible for the switch statement to operate
>|on any type that has an == operator defined; of course the case labels would
>|have to be the correct type (or coerced thereto).
>
>You have to be far more restrictive than that.  Not only must
>operator== be defined, but it must be defined to return a scalar (since
>the controlling expression of an if statement must have scalar type).
>Note:  you can't easily use implicit type conversion, since there is no
>way of telling which of the scalar types (pointer, float, int, etc.)
>the return value should meaningfully be converted to.

I would think that either the switch() operand's type or the case operand's
type would be used.  Most probably case, since that would allow greater
flexibility.  This would imply:

  switch(x)
  {
    case y:
    ...
  }

In this instance, the above would be the same as (y == x), which would use the
type of (y) and convert (x) to that type for the compare.


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