🚀 go-pugleaf

  I agree with most of the points made in this discussion, but Dan Pierson
included one sentence that troubles me:

> Also C++ still lacks exception handling which I rate about
> equal to object orientation as an essential language feature.

  I disagree somewhat about the importance of exception handling, but that's
beside the point.  I'm troubled by the view that "object orientation"
(or exception handling) should be a language feature.  I agree that
object-oriented programming is an extremely useful methodology.  But
casting it in stone by directly embedding one view of it into the language
design seems to be precisely what the "Bondage & Discipline" languages are
about  (although they of course generally did it for a less modern
methodology).
  I would certainly agree that a language should make it easy to program
using an object oriented methodology.  But I would be much more convinced
if this happened because the language design was sufficiently general
that it could express the necessary concepts rather
than because someone specifically tacked on the necessary
constructs.  Both classes and objects are really just tuples of things.
Inheritance amounts to adding elements to a tuple.  If I can't express these
without adding new language constructs, isn't there something wrong with my
language that has little to do with object orientation?  I also wouldn't
have much confidence that it could survive the next minor change in
methodology.
  Similarly, if I want exceptions, I would be happier with first-class
continuations, perhaps together with a library implementing your favorite
style of exception handling, than I would be with a new language primitive.
  Admittedly, some of this raises incompletely resolved issues
in language and compiler design (which is of course one legitimate reason
for the popularity of languages like C++).  But there are languages that
come close to achieving these things.  Scheme, as well as a variety of
more experimental statically typed languages come to mind.
  I may have read a lot into Dan Pierson's statement that he didn't
think he said.  If so, I apologize.

Hans-J. Boehm
boehm@rice.edu