Path: utzoo!attcan!uunet!samsung!usc!elroy.jpl.nasa.gov!ames!amdahl!pacbell!well!nagle
From: nagle@well.sf.ca.us (John Nagle)
Newsgroups: comp.lang.c++
Subject: What to do about generics and polymorphism in C++
Message-ID: <16808@well.sf.ca.us>
Date: 22 Mar 90 05:11:24 GMT
Reply-To: nagle@well.UUCP (John Nagle)
Lines: 27


      Let's start a discussion about the problem of how to achieve
generic objects (ones with types as parameters, at least at compile
time) in C++.  Some possibilities:

      1.  Explicitly use "pointer to void".  Works, but violates
	  type safety and requires much repetitive writing.

      2.  Encapsulate the necessary messy definitions in preprocessor
	  defines, as shown in "The C Answer Book".  Ugly and tends
	  to produce confusing error messages when trouble occurs.
	  May not be type safe.

      3.  Add compile-time generic facilities along the lines of those
	  in Ada to the language.  Provides similar functionality to
	  #2, with proper checking and diagnostics, but requires
	  a language change.

      4.  Add types as first-class objects, as in Smalltalk, so that
	  one can have type-valued variables and can do declarations
	  at run time.

      5.  Other?

Comments?

						John Nagle