# clang pseudoparser This directory implements an approximate heuristic parser for C++, based on the clang lexer, the C++ grammar, and the GLR parsing algorithm. It parses a file in isolation, without reading its included headers. The result is a strict syntactic tree whose structure follows the C++ grammar. There is no semantic analysis, apart from guesses to disambiguate the parse. Disambiguation can optionally be guided by an AST or a symbol index. For now, the best reference on intended scope is the [design proposal], with further discussion on the [RFC]. ## Dependencies between pseudoparser and clang Dependencies are limited because they don't make sense, but also to avoid placing a burden on clang mantainers. The pseudoparser reuses the clang lexer (clangLex and clangBasic libraries) but not the higher-level libraries (Parse, Sema, AST, Frontend...). When the pseudoparser should be used together with an AST (e.g. to guide disambiguation), this is a separate "bridge" library that depends on both. Clang does not depend on the pseudoparser at all. If this seems useful in future it should be discussed by RFC. ## Parity between pseudoparser and clang The pseudoparser aims to understand real-world code, and particularly the languages and extensions supported by Clang. However we don't try to keep these in lockstep: there's no expectation that Clang parser changes are accompanied by pseudoparser changes or vice versa. [design proposal]: https://docs.google.com/document/d/1eGkTOsFja63wsv8v0vd5JdoTonj-NlN3ujGF0T7xDbM/edit [RFC]: https://discourse.llvm.org/t/rfc-a-c-pseudo-parser-for-tooling/59217/49