|
|
|
|
|
|
by userbinator
3663 days ago
|
|
|
I'm curious to know your reasoning behind using a generated parser instead of writing your own. This might be the first "just for fun" C compiler I've seen on HN or elsewhere that doesn't use some variant of recursive-descent/precedence, which is employed even by the "real" compilers like GCC, Clang, ICC, and MSVC. If you are doing this for learning then I'd recommend studying C4's parser (https://news.ycombinator.com/item?id=8558822 ) and this article: https://www.engr.mun.ca/~theo/Misc/exp_parsing.htm The precedence-climbing algorithm is so amazingly simple and concise that I think anyone playing with compilers should implement a parser using it at least once, just to experience its astounding elegance. IMHO seeing an entire programming language's AST parsed almost entirely using a single recursive function with very little code and a table concisely describing its grammar can be quite exhilarating. |
|
|
I recently implemented a toy interpreter for a small language which uses a hand-written, table-driven shift-reduce parser. The parser simply maintains a stack of terminals and non-terminals and applies the corresponding reduction if a suffix of the stack matches a rule in the table. Precedence rules are resolved through an additional "should_shift" function, keeping the grammar very understandable. I think it's a very elegant algorithm:
https://github.com/bbu/simple-interpreter