16 Feb
2025
16 Feb
'25
12:30 p.m.
On Sun, 2025-02-16 at 13:08 -0500, Paul Koning via cctalk wrote:
Parsing -- splitting text into tokens (lexing) and
building parse
trees -- is part of the compiler's job but usually the easiest part.
Not quite as easy if you want good error messages or error recovery.
I put an LR parser generator that includes Tom Pennello's Forward Move
Algorithm for error recovery
at https://sourceforge.net/projects/lr-and-lex-gen-fortran/files//?upload_just…
It uses Dave Pager's algorithm to generate LALR where possible, and LR
where necessary, that is, when states with identical core cannot be
merged because of lookahead conflicts.
I stopped working on it when I retired.
The full exploitation of the extra information in the LR table isn't
implemented in the simple parser inside of the parser generator.