如何通过liblua获取Lua抽象语法树？C++下还有哪些替代解析方案？

Great question! Let's break this down based on your requirements:

Out of the box, the standard liblua doesn't expose a public API to get an Abstract Syntax Tree (AST) directly. Its internal parser (luaY_parser in the source code) is built to generate bytecode for execution, not a structured AST intended for external use.

That said, since Lua is open-source, you do have a couple of workarounds if you're already embedding liblua in your app:

• Modify the liblua source code: You can extend the internal parser to build and expose an AST structure. The parser in lparser.c creates syntax nodes internally during parsing—you can add logic to collect these nodes into a usable AST and expose it via custom C API functions. This keeps you aligned with the official Lua parser's behavior, which is ideal for full compatibility.
• Use debug hooks (limited utility): The Lua debug library can give you some runtime insights into code structure (like function definitions), but this isn't a true static AST. It only reflects code that actually executes, so it won't capture unused branches, static variable declarations, or the full syntax structure of unrun code.

If modifying liblua isn't feasible, here are solid independent options for parsing Lua into an AST in C++:

• LuaParser: A dedicated C++ library built specifically to parse Lua code and generate a fully traversable AST. It supports Lua versions 5.1 through 5.4, has a clean C++ API, and operates independently of the official liblua. You can easily iterate over nodes, inspect expressions, statements, and all syntax elements.
• Luau Parser: Luau is Roblox's optimized Lua dialect, but its parser is highly compatible with standard Lua. It provides a C++ API to parse Lua code into an AST, with excellent performance and support for modern Lua features. You can embed just the parser component without needing the full Luau runtime if that's all you require.
• Lightweight Community Parsers: There are smaller, community-maintained C++ parsers that implement Lua's syntax via recursive descent. These are great if you need a minimal footprint, but be sure to verify their compatibility with your target Lua version and ongoing maintenance status.
• Build Your Own Recursive Descent Parser: Lua's grammar is relatively simple and unambiguous, making a recursive descent parser straightforward to implement if you only need to handle a specific subset of Lua syntax. This gives you full control over the AST structure and parsing behavior.

内容的提问来源于stack exchange，提问作者fferri