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From: pat@frumious.uucp (Patrick Smith)
Subject: Re: Type System
Message-ID: <C0Iy9o.9x@frumious.uucp>
Date: Fri, 8 Jan 1993 07:32:11 GMT
Reply-To: uunet.ca!frumious!pat
References: <1993Jan1.172044.9659@ucc.su.OZ.AU> <1993Jan4.194318.5340@lucid.com>
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jss@lucid.com (Jerry Schwarz) writes:
|The way I understand it, when an object is created (constructed)
|it can be "marked" as mutable or immutable. ("Marked" in quotes
|because no runtime marking is implied).  This mark cannot be
|changed.  The type system is designed so that (barring the
|use of unsafe casts) the following rule is assured.
|
|	If an lvalue has non-const type,
|	then it refers to a mutable object.

There is another loophole. :-(
But it's (I hope) an unusual type of situation. :-)

   struct A { A(); /*...*/ };
   A* pa;
   A::A { pa = this; }

   void f() {
      const A a;
      // Now pa has non-const type but points to an immutable object.
   }

-- 
Patrick Smith
uunet.ca!frumious!pat
pat%frumious.uucp@uunet.ca