Re: Union Type Object problem

[Laurence Finston]

On Wed, 11 Aug 2004, Hans Aberg wrote:

> In discussion in the LaTeX3 project list
> <address@hidden>, one said that Don shunned parser
> generators and grammars when he did the TeX stuff. So, therefore TeX is as
> it is, and it may difficult to use a parser generator to do a program that
> exactly duplicates the original TeX-cluster of programs.
>

The TeX and Metafont languages are quite different, but they're similar
in that they use a very low-level approach to programming.
In a way, Knuth's approach was like using Pascal to write machine
language.
While I admire it, but I have no ambitions of emulating it, at least not
in 3DLDF.  Knuth does things like using sequences of bits within a machine
word to store information about objects.  I've chosen to use common tools
like Bison and the features supplied by C++.  I believe this will make my
program more readily understandable to more people and that this
outweighs any consequent loss of efficiency.

While I can't prove it, I do believe that some things the Metafont parser
does cannot be implemented using Bison.  I originally planned to try to
make it possible for 3DLDF to process valid Metafont and MetaPost code.
I've given up on this.  I also prefer a more succinct C-like syntax, so
the 3DLDF language has begun to diverge from MF/MP.

Laurence