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use std::{convert::From, fmt::Display, string::String}; use ast::{Expr, Stmt}; use lalrpop_util::{lalrpop_mod, ParseError}; use thiserror::Error; pub mod ast; lalrpop_mod!(#[allow(clippy::all)] pub grammar); #[derive(Debug, Error, Clone)] pub enum SyntaxError { #[error("{0}")] Generic(String), #[error("Expected {0}.")] Expected(String), #[error("Expected {0}; found token '{1}'.")] UnexpectedToken(String, String), #[error("Found extra token {0}.")] ExtraToken(String), #[error("Invalid token.")] Invalid, } type Result<T> = std::result::Result<T, SyntaxError>; impl<T1, T2> From<ParseError<usize, T1, T2>> for SyntaxError where T1: Display, T2: Into<String>, { fn from(error: ParseError<usize, T1, T2>) -> Self { match error { ParseError::InvalidToken { location: _ } => SyntaxError::Invalid, ParseError::UnrecognizedEOF { location: _, expected, } => SyntaxError::Expected(expected.join(", ")), ParseError::UnrecognizedToken { token, expected } => { SyntaxError::UnexpectedToken(expected.join(", "), token.1.to_string()) } ParseError::ExtraToken { token } => SyntaxError::ExtraToken(token.1.to_string()), ParseError::User { error } => SyntaxError::Generic(error.into()), } } } pub trait Parser<T> { fn parse_ast(input: &'_ str) -> Result<T>; } impl Parser<Vec<Box<Stmt>>> for crate::grammar::StmtsParser { fn parse_ast(input: &'_ str) -> Result<Vec<Box<Stmt>>> { let parser = crate::grammar::StmtsParser::new(); let mut errors = Vec::new(); let expr = parser.parse(&mut errors, input); if errors.is_empty() { Ok(expr.unwrap()) } else { Err(errors.pop().unwrap().into()) } } } impl Parser<Box<Expr>> for crate::grammar::ExprParser { fn parse_ast(input: &'_ str) -> Result<Box<Expr>> { let parser = crate::grammar::ExprParser::new(); let mut errors = Vec::new(); let expr = parser.parse(&mut errors, input); if errors.is_empty() { Ok(expr.unwrap()) } else { Err(errors.pop().unwrap().into()) } } } mod tests { #![allow(unused_imports)] use crate::{ ast::Expr, grammar::{ExprParser, StmtsParser}, Parser, }; #[test] fn parse_function_stmt() { let stmt = StmtsParser::parse_ast("fn test() { 3 };").unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Function("test", [], Block([], Some(Constant(Number(3.0)))))]"# ); let stmt = StmtsParser::parse_ast("fn test(t1, t2, t3,) { 3 };").unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Function("test", ["t1", "t2", "t3"], Block([], Some(Constant(Number(3.0)))))]"# ); } #[test] fn parse_declaration_stmt() { let stmt = StmtsParser::parse_ast("const test = 5.2 * 3;").unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Const("test", Binary(Constant(Number(5.2)), Multiply, Constant(Number(3.0))))]"# ); let stmt = StmtsParser::parse_ast("let test = 5.2 * 3;").unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Let("test", Some(Binary(Constant(Number(5.2)), Multiply, Constant(Number(3.0)))))]"# ); let stmt = StmtsParser::parse_ast("let test = 22.5 * if true {3} else {4};").unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Let("test", Some(Binary(Constant(Number(22.5)), Multiply, If(Constant(True), Block([], Some(Constant(Number(3.0)))), Some(Block([], Some(Constant(Number(4.0)))))))))]"# ); let stmt = StmtsParser::parse_ast("let test;").unwrap(); assert_eq!(&format!("{:?}", stmt), r#"[Let("test", None)]"#); } #[test] fn parse_return_stmt() { let stmt = StmtsParser::parse_ast(r#"return "howdy!";"#).unwrap(); assert_eq!( &format!("{:?}", stmt), r#"[Return(Some(Constant(String("\"howdy!\""))))]"# ); } #[test] fn parse_expression_stmt() { let stmt = StmtsParser::parse_ast("22.5 * (44 + 66);").unwrap(); assert_eq!( &format!("{:?}", stmt), "[Expression(Binary(Constant(Number(22.5)), Multiply, Binary(Constant(Number(44.0)), Add, Constant(Number(66.0)))))]" ); } #[test] fn parse_block_expr() { let expr = ExprParser::parse_ast("{15 + 1; 3}").unwrap(); assert_eq!( &format!("{:?}", expr), "Block([Expression(Binary(Constant(Number(15.0)), Add, Constant(Number(1.0))))], Some(Constant(Number(3.0))))" ); } #[test] fn parse_if_expr() { let expr = ExprParser::parse_ast(r#"if 3 == "3" {15 + 1; 3}"#).unwrap(); assert_eq!( &format!("{:?}", expr), r#"If(Binary(Constant(Number(3.0)), Equal, Constant(String("\"3\""))), Block([Expression(Binary(Constant(Number(15.0)), Add, Constant(Number(1.0))))], Some(Constant(Number(3.0)))), None)"# ); let expr = ExprParser::parse_ast("if 3 {3} else if 6 {6}").unwrap(); assert_eq!( &format!("{:?}", expr), "If(Constant(Number(3.0)), Block([], Some(Constant(Number(3.0)))), Some(If(Constant(Number(6.0)), Block([], Some(Constant(Number(6.0)))), None)))" ); } #[test] fn parse_while_expr() { let expr = ExprParser::parse_ast("while true {15 + 1;}").unwrap(); assert_eq!( &format!("{:?}", expr), "While(Constant(True), [Expression(Binary(Constant(Number(15.0)), Add, Constant(Number(1.0))))])" ); } #[test] fn parse_log_expr() { let expr = ExprParser::parse_ast(r#"log(a = "arg")"#).unwrap(); assert_eq!( &format!("{:?}", expr), r#"Log(Assign(Constant(Ident("a")), Assign, Constant(String("\"arg\""))))"# ); } #[test] fn parse_assign_expr() { let expr = ExprParser::parse_ast("a = 5").unwrap(); assert_eq!( &format!("{:?}", expr), r#"Assign(Constant(Ident("a")), Assign, Constant(Number(5.0)))"# ); let expr = ExprParser::parse_ast("a *= b = 5").unwrap(); assert_eq!( &format!("{:?}", expr), r#"Assign(Constant(Ident("a")), MultiplyAssign, Assign(Constant(Ident("b")), Assign, Constant(Number(5.0))))"# ); } #[test] fn parse_binary_expr() { let expr = ExprParser::parse_ast("22.5 * -44 + 66").unwrap(); assert_eq!( &format!("{:?}", expr), "Binary(Binary(Constant(Number(22.5)), Multiply, Unary(Negate, Constant(Number(44.0)))), Add, Constant(Number(66.0)))" ); } #[test] fn parse_call_expr() { let expr = ExprParser::parse_ast("test(3 * 5, 4,)").unwrap(); assert_eq!( &format!("{:?}", expr), r#"Call(Constant(Ident("test")), [Binary(Constant(Number(3.0)), Multiply, Constant(Number(5.0))), Constant(Number(4.0))])"# ); } #[test] fn parse_complex_tuples() { let expr = ExprParser::parse_ast(r#"#[1, 3, 5, #["test", "I hope this works!!"]]"#).unwrap(); assert_eq!( &format!("{:?}", expr), r#"Constant(Tuple([Constant(Number(1.0)), Constant(Number(3.0)), Constant(Number(5.0)), Constant(Tuple([Constant(String("\"test\"")), Constant(String("\"I hope this works!!\""))]))]))"# ); let expr = ExprParser::parse_ast(r#"#[1, 3, 5, #["test", "I hope this works!!"]][3][1]"#).unwrap(); assert_eq!( &format!("{:?}", expr), r#"Index(Index(Constant(Tuple([Constant(Number(1.0)), Constant(Number(3.0)), Constant(Number(5.0)), Constant(Tuple([Constant(String("\"test\"")), Constant(String("\"I hope this works!!\""))]))])), Constant(Number(3.0))), Constant(Number(1.0)))"# ); } }