From 68b4e2d703e3b89b44084825786106e32b456c9c Mon Sep 17 00:00:00 2001 From: Sam McCall Date: Mon, 7 Mar 2022 13:45:44 +0100 Subject: [PATCH] [pseudo] Add readme Differential Revision: https://reviews.llvm.org/D121108 --- clang/lib/Tooling/Syntax/Pseudo/README.md | 37 +++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 clang/lib/Tooling/Syntax/Pseudo/README.md diff --git a/clang/lib/Tooling/Syntax/Pseudo/README.md b/clang/lib/Tooling/Syntax/Pseudo/README.md new file mode 100644 index 0000000..0958f5d --- /dev/null +++ b/clang/lib/Tooling/Syntax/Pseudo/README.md @@ -0,0 +1,37 @@ +# 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 -- 2.7.4