C++ parsing being undecidable, and C having the Most Vexing Parse, are the classic arguments for developing a grammar using a parser generator, and only when the grammar is mature, write a handrolled implementation using the grammar as a reference.

I happen to think generating useful software from declarative grammar specifications is, hmm. Not limited to what such frameworks have been capable of to date. Although if you've only worked with yacc/bison, and never ANTLR, you may be underestimating the quality of a generated parser with respect to error recovery and messages. The state of the art has advanced, I don't think anyone would claim parity with artisanal handcrafted softwares, but we can get a lot more than "barf: shift-reduce bunchanumbers" these days.