From: Doug Gregor [mailto:dgregor@cs.indiana.edu] Sent: September 30, 2004 10:30
I should mention that the design of the C++ parser allows to manipulate the generated parse tree in-memory and write it out into a file again in a non-lossy way, i.e. it could indeed be used as a source-to-source compiler.
That's an excellent goal, and you have me interested. It's a huge task, requiring a great deal of expertise (collectively, we have that) and will require a lot of time. I think it would be wise to attempt to isolate some of the interesting-but-disjoint problems early, so we can put out a "request for libraries" of some sort. Things that come to mind quickly: a unification algorithm (for template instantiation/partial ordering), a tree manipulation/rewriting library (for AST transformations), and a flexible symbol table library.
in what sense do you use the term 'library' here ? While I fully agree that is is very useful to approach this big task by splitting it into modules, I doubt it is feasible or even useful to use these entities as separate deployment units. However, I think we can come up with a high level design that respects the data flow requirements (the complex interactions between the parser and the symbol lookup table notably) yet is flexible enough to let the individual modules evolve in parallel. In fact, I have good hope that I could use the same framework to analyze C code (something I hope the Free Software community around GNOME / GNU will benefit from) by using some form of polymorphism in the lexer, the parser, and the symbol lookup. Regards, Stefan