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parser.rs
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use std::iter;
use crate::ast;
use crate::error::ParseError;
use crate::lexer;
use crate::python;
use crate::token;
/*
* Parse python code.
* Grammar may be inspired by antlr grammar for python:
* https://github.com/antlr/grammars-v4/tree/master/python3
*/
macro_rules! do_lalr_parsing {
($input: expr, $pat: ident, $tok: ident) => {{
let lxr = lexer::make_tokenizer($input);
let marker_token = (Default::default(), token::Tok::$tok, Default::default());
let tokenizer = iter::once(Ok(marker_token)).chain(lxr);
match python::TopParser::new().parse(tokenizer) {
Err(err) => Err(ParseError::from(err)),
Ok(top) => {
if let ast::Top::$pat(x) = top {
Ok(x)
} else {
unreachable!()
}
}
}
}};
}
pub fn parse_program(source: &str) -> Result<ast::Program, ParseError> {
do_lalr_parsing!(source, Program, StartProgram)
}
pub fn parse_statement(source: &str) -> Result<Vec<ast::LocatedStatement>, ParseError> {
do_lalr_parsing!(source, Statement, StartStatement)
}
/// Parses a python expression
///
/// # Example
/// ```
/// extern crate num_bigint;
/// use num_bigint::BigInt;
/// use rustpython_parser::{parser, ast};
/// let expr = parser::parse_expression("1+2").unwrap();
///
/// assert_eq!(ast::Expression::Binop {
/// a: Box::new(ast::Expression::Number {
/// value: ast::Number::Integer { value: BigInt::from(1) }
/// }),
/// op: ast::Operator::Add,
/// b: Box::new(ast::Expression::Number {
/// value: ast::Number::Integer { value: BigInt::from(2) }
/// })
/// },
/// expr);
///
/// ```
pub fn parse_expression(source: &str) -> Result<ast::Expression, ParseError> {
do_lalr_parsing!(source, Expression, StartExpression)
}
#[cfg(test)]
mod tests {
use super::ast;
use super::parse_expression;
use super::parse_program;
use super::parse_statement;
use num_bigint::BigInt;
#[test]
fn test_parse_empty() {
let parse_ast = parse_program(&String::from("\n"));
assert_eq!(parse_ast, Ok(ast::Program { statements: vec![] }))
}
#[test]
fn test_parse_print_hello() {
let source = String::from("print('Hello world')\n");
let parse_ast = parse_program(&source).unwrap();
assert_eq!(
parse_ast,
ast::Program {
statements: vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Expression {
expression: ast::Expression::Call {
function: Box::new(ast::Expression::Identifier {
name: String::from("print"),
}),
args: vec![ast::Expression::String {
value: ast::StringGroup::Constant {
value: String::from("Hello world")
}
}],
keywords: vec![],
},
},
},],
}
);
}
#[test]
fn test_parse_print_2() {
let source = String::from("print('Hello world', 2)\n");
let parse_ast = parse_program(&source).unwrap();
assert_eq!(
parse_ast,
ast::Program {
statements: vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Expression {
expression: ast::Expression::Call {
function: Box::new(ast::Expression::Identifier {
name: String::from("print"),
}),
args: vec![
ast::Expression::String {
value: ast::StringGroup::Constant {
value: String::from("Hello world"),
}
},
ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(2)
},
}
],
keywords: vec![],
},
},
},],
}
);
}
#[test]
fn test_parse_kwargs() {
let source = String::from("my_func('positional', keyword=2)\n");
let parse_ast = parse_program(&source).unwrap();
assert_eq!(
parse_ast,
ast::Program {
statements: vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Expression {
expression: ast::Expression::Call {
function: Box::new(ast::Expression::Identifier {
name: String::from("my_func"),
}),
args: vec![ast::Expression::String {
value: ast::StringGroup::Constant {
value: String::from("positional"),
}
}],
keywords: vec![ast::Key
7440
word {
name: Some("keyword".to_string()),
value: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(2)
},
}
}],
},
},
},],
}
);
}
#[test]
fn test_parse_if_elif_else() {
let source = String::from("if 1: 10\nelif 2: 20\nelse: 30\n");
let parse_ast = parse_statement(&source).unwrap();
assert_eq!(
parse_ast,
vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::If {
test: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(1)
},
},
body: vec![ast::LocatedStatement {
location: ast::Location::new(1, 7),
node: ast::Statement::Expression {
expression: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(10)
},
}
},
},],
orelse: Some(vec![ast::LocatedStatement {
location: ast::Location::new(2, 1),
node: ast::Statement::If {
test: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(2)
},
},
body: vec![ast::LocatedStatement {
location: ast::Location::new(2, 9),
node: ast::Statement::Expression {
expression: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(20)
},
},
},
},],
orelse: Some(vec![ast::LocatedStatement {
location: ast::Location::new(3, 7),
node: ast::Statement::Expression {
expression: ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(30)
},
},
},
},]),
}
},]),
}
}]
);
}
#[test]
fn test_parse_lambda() {
let source = String::from("lambda x, y: x * y\n"); // lambda(x, y): x * y");
let parse_ast = parse_statement(&source);
assert_eq!(
parse_ast,
Ok(vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Expression {
expression: ast::Expression::Lambda {
args: ast::Parameters {
args: vec![
ast::Parameter {
arg: String::from("x"),
annotation: None,
},
ast::Parameter {
arg: String::from("y"),
annotation: None,
}
],
kwonlyargs: vec![],
vararg: ast::Varargs::None,
kwarg: ast::Varargs::None,
defaults: vec![],
kw_defaults: vec![],
},
body: Box::new(ast::Expression::Binop {
a: Box::new(ast::Expression::Identifier {
name: String::from("x"),
}),
op: ast::Operator::Mult,
b: Box::new(ast::Expression::Identifier {
name: String::from("y"),
})
})
}
}
}])
)
}
#[test]
fn test_parse_tuples() {
let source = String::from("a, b = 4, 5\n");
assert_eq!(
parse_statement(&source),
Ok(vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Assign {
targets: vec![ast::Expression::Tuple {
elements: vec![
ast::Expression::Identifier {
name: "a".to_string()
},
ast::Expression::Identifier {
name: "b".to_string()
}
]
}],
value: ast::Expression::Tuple {
elements: vec![
ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(4)
}
},
ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(5)
}
}
]
}
}
}])
)
}
#[test]
fn test_parse_class() {
let source = String::from(
"class Foo(A, B):\n def __init__(self):\n pass\n def method_with_default(self, arg='default'):\n pass\n",
);
assert_eq!(
parse_statement(&source),
Ok(vec![ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::ClassDef {
name: String::from("Foo"),
bases: vec![
ast::Expression::Identifier {
name: String::from("A")
},
ast::Expression::Identifier {
name: String::from("B")
}
],
keywords: vec![],
body: vec![
ast::LocatedStatement {
location: ast::Location::new(2, 2),
node: ast::Statement::FunctionDef {
name: String::from("__init__"),
args: ast::Parameters {
args: vec![ast::Parameter {
arg: String::from("self"),
annotation: None,
}],
kwonlyargs: vec![],
vararg: ast::Varargs::None,
kwarg: ast::Varargs::None,
defaults: vec![],
kw_defaults: vec![],
},
body: vec![ast::LocatedStatement {
location: ast::Location::new(3, 3),
node: ast::Statement::Pass,
}],
decorator_list: vec![],
returns: None,
}
},
ast::LocatedStatement {
location: ast::Location::new(4, 2),
node: ast::Statement::FunctionDef {
name: String::from("method_with_default"),
args: ast::Parameters {
args: vec![
ast::Parameter {
arg: String::from("self"),
annotation: None,
},
ast::Parameter {
arg: String::from("arg"),
annotation: None,
}
],
kwonlyargs: vec![],
vararg: ast::Varargs::None,
kwarg: ast::Varargs::None,
defaults: vec![ast::Expression::String {
value: ast::StringGroup::Constant {
value: "default".to_string()
}
}],
kw_defaults: vec![],
},
body: vec![ast::LocatedStatement {
location: ast::Location::new(5, 3),
node: ast::Statement::Pass,
}],
decorator_list: vec![],
returns: None,
}
}
],
decorator_list: vec![],
}
}])
)
}
#[test]
fn test_parse_list_comprehension() {
let source = String::from("[x for y in z]");
let parse_ast = parse_expression(&source).unwrap();
assert_eq!(
parse_ast,
ast::Expression::Comprehension {
kind: Box::new(ast::ComprehensionKind::List {
element: ast::Expression::Identifier {
name: "x".to_string()
}
}),
generators: vec![ast::Comprehension {
target: ast::Expression::Identifier {
name: "y".to_string()
},
iter: ast::Expression::Identifier {
name: "z".to_string()
},
ifs: vec![],
}],
}
);
}
#[test]
fn test_parse_double_list_comprehension() {
let source = String::from("[x for y, y2 in z for a in b if a < 5 if a > 10]");
let parse_ast = parse_expression(&source).unwrap();
assert_eq!(
parse_ast,
ast::Expression::Comprehension {
kind: Box::new(ast::ComprehensionKind::List {
element: ast::Expression::Identifier {
name: "x".to_string()
}
}),
generators: vec![
ast::Comprehension {
target: ast::Expression::Tuple {
elements: vec![
ast::Expression::Identifier {
name: "y".to_string()
},
ast::Expression::Identifier {
name: "y2".to_string()
},
],
},
iter: ast::Expression::Identifier {
name: "z".to_string()
},
ifs: vec![],
},
ast::Comprehension {
target: ast::Expression::Identifier {
name: "a".to_string()
},
iter: ast::Expression::Identifier {
name: "b".to_string()
},
ifs: vec![
ast::Expression::Compare {
vals: vec![
ast::Expression::Identifier {
name: "a".to_string()
},
ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(5)
}
}
],
ops: vec![ast::Comparison::Less],
},
ast::Expression::Compare {
vals: vec![
ast::Expression::Identifier {
name: "a".to_string()
},
ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(10)
}
}
],
ops: vec![ast::Comparison::Greater],
},
],
}
],
}
);
}
}