[cakoose]

That claim is sort misleading. The complexity of the specification's own grammar is largely unrelated to it's expressiveness.

I'd expect most parser generators in this category to be able to parse their own grammars.

Imagine a very weak parser that can only handle LR0. But if it uses a Lisp-like grammar language, it too is self-hosting.

[kazinator]

> The complexity of the specification's own grammar is largely unrelated to it's expressiveness.

E.g.:

  bitstring : bistring '1'
            | bitstring '0'
            | /* empty */
            ;

this expresses all that can be expressed. The rest is semantics.

[jzimmerman64]

The language of BNF for langcc (https://github.com/jzimmerman/langcc/blob/main/grammars/meta...) provides many syntactic conveniences that are not present in a Lisp-like language, so the fact that langcc supports it is a nontrivial achievement. In particular, an LR(0) parser would not be anywhere near adequate for it.

[cakoose]

I wasn't saying langcc was not powerful, just that the shape of the argument doesn't make sense.

That part of the README goes something like this:

1. It can parse Python and Go efficiently.

2. In fact it's so expressive that it can even parse itself, which is a "language of languages".

If you had first shown some hard-to-parse langcc syntax, then sure, _that_ would be evidence of expressiveness. But there's nothing impressive about being able to parse a "language of languages", since a language of languages can be LR(0).