forked from M-Labs/nac3
168 lines
4.8 KiB
Rust
168 lines
4.8 KiB
Rust
//! Python parsing.
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//!
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//! Use this module to parse python code into an AST.
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//! There are three ways to parse python code. You could
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//! parse a whole program, a single statement, or a single
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//! expression.
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use std::iter;
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use crate::ast;
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use crate::error::ParseError;
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use crate::lexer;
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pub use crate::mode::Mode;
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use crate::python;
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/*
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* Parse python code.
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* Grammar may be inspired by antlr grammar for python:
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* https://github.com/antlr/grammars-v4/tree/master/python3
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*/
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/// Parse a full python program, containing usually multiple lines.
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pub fn parse_program(source: &str) -> Result<ast::Suite, ParseError> {
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parse(source, Mode::Module).map(|top| match top {
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ast::Mod::Module { body, .. } => body,
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_ => unreachable!(),
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})
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}
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/// Parses a python expression
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///
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/// # Example
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/// ```
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/// extern crate num_bigint;
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/// use nac3parser::{parser, ast};
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/// let expr = parser::parse_expression("1 + 2").unwrap();
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///
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/// assert_eq!(
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/// expr,
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/// ast::Expr {
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/// location: ast::Location::new(1, 3),
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/// custom: (),
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/// node: ast::ExprKind::BinOp {
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/// left: Box::new(ast::Expr {
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/// location: ast::Location::new(1, 1),
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/// custom: (),
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/// node: ast::ExprKind::Constant {
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/// value: ast::Constant::Int(1.into()),
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/// kind: None,
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/// }
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/// }),
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/// op: ast::Operator::Add,
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/// right: Box::new(ast::Expr {
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/// location: ast::Location::new(1, 5),
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/// custom: (),
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/// node: ast::ExprKind::Constant {
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/// value: ast::Constant::Int(2.into()),
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/// kind: None,
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/// }
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/// })
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/// }
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/// },
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/// );
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///
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/// ```
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pub fn parse_expression(source: &str) -> Result<ast::Expr, ParseError> {
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parse(source, Mode::Expression).map(|top| match top {
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ast::Mod::Expression { body } => *body,
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_ => unreachable!(),
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})
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}
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// Parse a given source code
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pub fn parse(source: &str, mode: Mode) -> Result<ast::Mod, ParseError> {
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let lxr = lexer::make_tokenizer(source);
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let marker_token = (Default::default(), mode.to_marker(), Default::default());
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let tokenizer = iter::once(Ok(marker_token)).chain(lxr);
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python::TopParser::new()
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.parse(tokenizer)
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.map_err(ParseError::from)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_parse_empty() {
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let parse_ast = parse_program("").unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_print_hello() {
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let source = String::from("print('Hello world')");
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let parse_ast = parse_program(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_print_2() {
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let source = String::from("print('Hello world', 2)");
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let parse_ast = parse_program(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_kwargs() {
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let source = String::from("my_func('positional', keyword=2)");
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let parse_ast = parse_program(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_if_elif_else() {
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let source = String::from("if 1: 10\nelif 2: 20\nelse: 30");
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let parse_ast = parse_program(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_lambda() {
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let source = "lambda x, y: x * y"; // lambda(x, y): x * y";
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let parse_ast = parse_program(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_tuples() {
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let source = "a, b = 4, 5";
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insta::assert_debug_snapshot!(parse_program(&source).unwrap());
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}
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#[test]
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fn test_parse_class() {
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let source = "\
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class Foo(A, B):
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def __init__(self):
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pass
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def method_with_default(self, arg='default'):
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pass";
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insta::assert_debug_snapshot!(parse_program(&source).unwrap());
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}
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#[test]
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fn test_parse_dict_comprehension() {
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let source = String::from("{x1: x2 for y in z}");
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let parse_ast = parse_expression(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_list_comprehension() {
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let source = String::from("[x for y in z]");
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let parse_ast = parse_expression(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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#[test]
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fn test_parse_double_list_comprehension() {
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let source = String::from("[x for y, y2 in z for a in b if a < 5 if a > 10]");
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let parse_ast = parse_expression(&source).unwrap();
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insta::assert_debug_snapshot!(parse_ast);
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}
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}
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