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parser.rs
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684 lines (650 loc) · 24.7 KB
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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<ast::LocatedStatement, ParseError> {
do_lalr_parsing!(source, Statement, StartStatement)
}
/// Parses a python expression
///
/// # Example
/// ```
/// extern crate num_bigint;
/// extern crate rustpython_parser;
/// 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:
10BC0
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)
}
// TODO: consolidate these with ParseError
#[derive(Debug, PartialEq)]
pub enum FStringError {
UnclosedLbrace,
UnopenedRbrace,
InvalidExpression,
}
impl From<FStringError>
for lalrpop_util::ParseError<lexer::Location, token::Tok, lexer::LexicalError>
{
fn from(_err: FStringError) -> Self {
lalrpop_util::ParseError::User {
error: lexer::LexicalError::StringError,
}
}
}
enum ParseState {
Text {
content: String,
},
FormattedValue {
expression: String,
spec: Option<String>,
depth: usize,
},
}
pub fn parse_fstring(source: &str) -> Result<ast::StringGroup, FStringError> {
use self::ParseState::*;
let mut values = vec![];
let mut state = ParseState::Text {
content: String::new(),
};
let mut chars = source.chars().peekable();
while let Some(ch) = chars.next() {
state = match state {
Text { mut content } => match ch {
'{' => {
if let Some('{') = chars.peek() {
chars.next();
content.push('{');
Text { content }
} else {
if !content.is_empty() {
values.push(ast::StringGroup::Constant { value: content });
}
FormattedValue {
expression: String::new(),
spec: None,
depth: 0,
}
}
}
'}' => {
if let Some('}') = chars.peek() {
chars.next();
content.push('}');
Text { content }
} else {
return Err(FStringError::UnopenedRbrace);
}
}
_ => {
content.push(ch);
Text { content }
}
},
FormattedValue {
mut expression,
mut spec,
depth,
} => match ch {
':' if depth == 0 => FormattedValue {
expression,
spec: Some(String::new()),
depth,
},
'{' => {
if let Some('{') = chars.peek() {
expression.push_str("{{");
chars.next();
FormattedValue {
expression,
spec,
depth,
}
} else {
expression.push('{');
FormattedValue {
expression,
spec,
depth: depth + 1,
}
}
}
'}' => {
if let Some('}') = chars.peek() {
expression.push_str("}}");
chars.next();
FormattedValue {
expression,
spec,
depth,
}
} else if depth > 0 {
expression.push('}');
FormattedValue {
expression,
spec,
depth: depth - 1,
}
} else {
values.push(ast::StringGroup::FormattedValue {
value: Box::new(match parse_expression(expression.trim()) {
Ok(expr) => expr,
Err(_) => return Err(FStringError::InvalidExpression),
}),
spec: spec.unwrap_or_default(),
});
Text {
content: String::new(),
}
}
}
_ => {
if let Some(spec) = spec.as_mut() {
spec.push(ch)
} else {
expression.push(ch);
}
FormattedValue {
expression,
spec,
depth,
}
}
},
};
}
match state {
Text { content } => {
if !content.is_empty() {
values.push(ast::StringGroup::Constant { value: content })
}
}
FormattedValue { .. } => {
return Err(FStringError::UnclosedLbrace);
}
}
Ok(match values.len() {
0 => ast::StringGroup::Constant {
value: String::new(),
},
1 => values.into_iter().next().unwrap(),
_ => ast::StringGroup::Joined { values },
})
}
#[cfg(test)]
mod tests {
use super::ast;
use super::parse_expression;
use super::parse_fstring;
use super::parse_program;
use super::parse_statement;
use super::FStringError;
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::Keyword {
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,
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(ast::LocatedStatement {
location: ast::Location::new(1, 1),
node: ast::Statement::Expression {
expression: ast::Expression::Lambda {
args: ast::Parameters {
args: vec![String::from("x"), String::from("y")],
kwonlyargs: vec![],
vararg: None,
kwarg: 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(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(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![String::from("self")],
kwonlyargs: vec![],
vararg: None,
kwarg: None,
defaults: vec![],
kw_defaults: vec![],
},
body: vec![ast::LocatedStatement {
location: ast::Location::new(3, 3),
node: ast::Statement::Pass,
}],
decorator_list: vec![],
}
},
ast::LocatedStatement {
location: ast::Location::new(4, 2),
node: ast::Statement::FunctionDef {
name: String::from("method_with_default"),
args: ast::Parameters {
args: vec![String::from("self"), String::from("arg"),],
kwonlyargs: vec![],
vararg: None,
kwarg: 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![],
}
}
],
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()
}
9886
}),
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 {
a: Box::new(ast::Expression::Identifier {
name: "a".to_string()
}),
op: ast::Comparison::Less,
b: Box::new(ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(5)
}
}),
},
ast::Expression::Compare {
a: Box::new(ast::Expression::Identifier {
name: "a".to_string()
}),
op: ast::Comparison::Greater,
b: Box::new(ast::Expression::Number {
value: ast::Number::Integer {
value: BigInt::from(10)
}
}),
},
],
}
],
}
);
}
fn mk_ident(name: &str) -> ast::Expression {
ast::Expression::Identifier {
name: name.to_owned(),
}
}
#[test]
fn test_parse_fstring() {
let source = String::from("{a}{ b }{{foo}}");
let parse_ast = parse_fstring(&source).unwrap();
assert_eq!(
parse_ast,
ast::StringGroup::Joined {
values: vec![
ast::StringGroup::FormattedValue {
value: Box::new(mk_ident("a")),
spec: String::new(),
},
ast::StringGroup::FormattedValue {
value: Box::new(mk_ident("b")),
spec: String::new(),
},
ast::StringGroup::Constant {
value: "{foo}".to_owned()
}
]
}
);
}
#[test]
fn test_parse_empty_fstring() {
assert_eq!(
parse_fstring(""),
Ok(ast::StringGroup::Constant {
value: String::new(),
}),
);
}
#[test]
fn test_parse_invalid_fstring() {
assert_eq!(parse_fstring("{"), Err(FStringError::UnclosedLbrace));
assert_eq!(parse_fstring("}"), Err(FStringError::UnopenedRbrace));
assert_eq!(
parse_fstring("{class}"),
Err(FStringError::InvalidExpression)
);
}
}