Vacietis

> You cannot parse it properly without symbol table. No context free parser handles C properly, let alone C++. It gets progressively and exponentially worse from here. C is actually pretty easy if you ignore all of the bad advice to use parser generators. I looked into the various YACC grammars for C I could find on the Internet, and all of them either had bugs or were incomplete. TCC[1] has a simple recursive-descent parser. With a recursive descent parser you also have the option of implementing the C pre-processor in the same step. Turns out I was able to implement a single-pass C parser and pre-processor as a bunch of Common Lisp read macros[2]. I have not looked into it, but the approach for C++ looks like it would be very different because template instantiation needs its own step. [1] https://bellard.org/tcc/ [2] https://github.com

> One of the few valid use cases of "goto" today. Manually rewriting recursive algorithms is one of the least valid use case of GOTO. You need GOTO for low-level concurrency, IO multiplexing, and transpiling: https://github.com/vsedach/Eager-Future2/blob/master/future.... https://github.com/vsedach/Vacietis/blob/master/compiler/imp...

They are not that hairy. I did a recursive-descent one as a Common Lisp reader macro in less than 1k loc: https://github.com/vsedach/Vacietis/blob/master/compiler/rea... C is ok in that you can handle everything (including typedefs) in a single pass with only one character lookahead. This includes the preprocessor. Common Lisp has concatenated streams (http://www.lispworks.com/documentation/HyperSpec/Body/t_conc...) which made handling the preprocessor really easy, but tcc (https://bellard.org/tcc/) and I think pcc also do the preprocessing as part of the parser.

The Vacietis (https://github.com/vsedach/Vacietis/) reader can be easily adapted to do that. You can see examples in the unit tests: https://github.com/vsedach/Vacietis/blob/master/test/reader-... As-is, C block constructs get mapped directly to Common Lisp special forms like tagbody and prog because those implement a superset of C control flow semantics. Pick different names in vacietis.c and you have an AST.