forked from M-Labs/nac3
67 lines
2.1 KiB
Markdown
67 lines
2.1 KiB
Markdown
# RustPython/parser
|
|
|
|
This directory has the code for python lexing, parsing and generating Abstract Syntax Trees (AST).
|
|
|
|
The steps are:
|
|
- Lexical analysis: splits the source code into tokens.
|
|
- Parsing and generating the AST: transforms those tokens into an AST. Uses `LALRPOP`, a Rust parser generator framework.
|
|
|
|
This crate is published on [https://docs.rs/rustpython-parser](https://docs.rs/rustpython-parser).
|
|
|
|
We wrote [a blog post](https://rustpython.github.io/2020/04/02/thing-explainer-parser.html) with screenshots and an explanation to help you understand the steps by seeing them in action.
|
|
|
|
For more information on LALRPOP, here is a link to the [LALRPOP book](https://github.com/lalrpop/lalrpop).
|
|
|
|
There is a readme in the `src` folder with the details of each file.
|
|
|
|
|
|
## Directory content
|
|
|
|
`build.rs`: The build script.
|
|
`Cargo.toml`: The config file.
|
|
|
|
The `src` directory has:
|
|
|
|
**lib.rs**
|
|
This is the crate's root.
|
|
|
|
**lexer.rs**
|
|
This module takes care of lexing python source text. This means source code is translated into separate tokens.
|
|
|
|
**parser.rs**
|
|
A python parsing module. Use this module to parse python code into an AST. There are three ways to parse python code. You could parse a whole program, a single statement, or a single expression.
|
|
|
|
**ast.rs**
|
|
Implements abstract syntax tree (AST) nodes for the python language. Roughly equivalent to [the python AST](https://docs.python.org/3/library/ast.html).
|
|
|
|
**python.lalrpop**
|
|
Python grammar.
|
|
|
|
**token.rs**
|
|
Different token definitions. Loosely based on token.h from CPython source.
|
|
|
|
**errors.rs**
|
|
Define internal parse error types. The goal is to provide a matching and a safe error API, masking errors from LALR.
|
|
|
|
**fstring.rs**
|
|
Format strings.
|
|
|
|
**function.rs**
|
|
Collection of functions for parsing parameters, arguments.
|
|
|
|
**location.rs**
|
|
Datatypes to support source location information.
|
|
|
|
**mode.rs**
|
|
Execution mode check. Allowed modes are `exec`, `eval` or `single`.
|
|
|
|
|
|
## How to use
|
|
|
|
For example, one could do this:
|
|
```
|
|
use rustpython_parser::{parser, ast};
|
|
let python_source = "print('Hello world')";
|
|
let python_ast = parser::parse_expression(python_source).unwrap();
|
|
```
|