🚀 go-pugleaf

In article <1e775rINNslq@network.ucsd.edu> mbk@lyapunov.ucsd.edu (Matt Kennel) writes:

     Prof. Rubin wants to use a syntax which cannot be parsed with the
   "standard" tools of compiler contruction kits.  Think of 
   the old standbys "lex 'n' yacc"---he essentially wants something in
   which the "tables" themselves could somehow be altered using langauge
   statements.  Maybe the world doesn't revolve around statically generated
   context-free unambiguous grammars.

   Too many computer scientists think that "syntax is trivial" or "syntax
   is uninteresting", which it may be to the inside of a compiler, but isn't
   to ordinary users.

Far from it. In fact, a lot of research in computer science is
directed at coming up with ways of letting people specify syntax and
syntactic transformations as conveniently as possible. Reality is that
this is a hard problem. That's why there are only compromises
available.

The available compromises are the following:

 * Programming languages themselves nowadays only let you specify very
   limited syntactic extensions, because such extensions are difficult
   to scope properly (mind you, the computer and the parser have no
   problem with this, it is the humans that can't deal with it).  This
   isn't the result of some kind of "language fascism", but of market
   forces: languages that have allowed more general syntactic
   extensions simply never caught on, presumably because such
   extensions were causing more hassle than they were worth.

 * Some programming languages use limited syntax but allow very
   general transformations (e.g., Lisp macros).

 * There are a number of general-purpose tools for writing systems
   that perform syntactic transformations (yacc, TXL, Prolog, ...).
   Such systems let you express just about any syntax you might want
   to, but because they are so powerful, they are more difficult to
   use.

Now, there is certainly room for improvement, so if you don't like
what you are getting right now, maybe you can come up with something
better.

					Thomas.