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use lalrpop_util;
use itertools::*;
use pest::Parser;
use pest::iterators::Pair;
use dhall_parser::{DhallParser, Rule};
use crate::grammar;
use crate::grammar_util::{BoxExpr, ParsedExpr};
use crate::lexer::{Lexer, LexicalError, Tok};
use crate::core::{bx, Expr, Builtin, V};
pub fn parse_expr_lalrpop(s: &str) -> Result<BoxExpr, lalrpop_util::ParseError<usize, Tok, LexicalError>> {
grammar::ExprParser::new().parse(Lexer::new(s))
}
pub type ParseError = pest::error::Error<Rule>;
pub type ParseResult<T> = Result<T, ParseError>;
pub fn custom_parse_error(pair: &Pair<Rule>, msg: String) -> ParseError {
let e = pest::error::ErrorVariant::CustomError{ message: msg };
pest::error::Error::new_from_span(e, pair.as_span())
}
macro_rules! parse_aux {
($inner:expr, true, $x:ident : $ty:ident $($rest:tt)*) => {
let $x = concat_idents!(parse_, $ty)($inner.next().unwrap())?;
parse_aux!($inner, true $($rest)*)
};
($inner:expr, true, $x:ident? : $ty:ident $($rest:tt)*) => {
let $x = $inner.next().map(concat_idents!(parse_, $ty)).transpose()?;
parse_aux!($inner, true $($rest)*)
};
($inner:expr, true, $x:ident* : $ty:ident $($rest:tt)*) => {
#[allow(unused_mut)]
let mut $x = $inner.map(concat_idents!(parse_, $ty));
parse_aux!($inner, false $($rest)*)
};
($inner:expr, false) => {};
($inner:expr, true) => {
$inner.next().ok_or(()).expect_err("Some parsed values remain unused")
};
}
macro_rules! parse {
($pair:expr; ($($args:tt)*) => $body:expr) => {
{
#[allow(unused_mut)]
let mut inner = $pair.into_inner();
parse_aux!(inner, true, $($args)*);
Ok($body)
}
};
}
fn parse_binop<'a, F>(pair: Pair<'a, Rule>, mut f: F) -> ParseResult<BoxExpr<'a>>
where F: FnMut(BoxExpr<'a>, BoxExpr<'a>) -> ParsedExpr<'a> {
parse!(pair; (first: expression, rest*: expression) => {
rest.fold_results(first, |acc, e| bx(f(acc, e)))?
})
}
fn skip_expr(pair: Pair<Rule>) -> ParseResult<BoxExpr> {
parse!(pair; (expr: expression) => {
expr
})
}
fn parse_str(pair: Pair<Rule>) -> ParseResult<&str> {
Ok(pair.as_str().trim())
}
fn parse_natural(pair: Pair<Rule>) -> ParseResult<usize> {
parse_str(pair.clone())?
.parse()
.map_err(|e: std::num::ParseIntError| custom_parse_error(&pair, format!("{}", e)))
}
fn parse_expression(pair: Pair<Rule>) -> ParseResult<BoxExpr> {
match pair.as_rule() {
Rule::natural_literal_raw => Ok(bx(Expr::NaturalLit(parse_natural(pair)?))),
Rule::annotated_expression => { parse_binop(pair, Expr::Annot) }
Rule::import_alt_expression => { skip_expr(pair) }
Rule::or_expression => { parse_binop(pair, Expr::BoolOr) }
Rule::plus_expression => { parse_binop(pair, Expr::NaturalPlus) }
Rule::text_append_expression => { parse_binop(pair, Expr::TextAppend) }
Rule::list_append_expression => { skip_expr(pair) }
Rule::and_expression => { parse_binop(pair, Expr::BoolAnd) }
Rule::combine_expression => { skip_expr(pair) }
Rule::prefer_expression => { skip_expr(pair) }
Rule::combine_types_expression => { skip_expr(pair) }
Rule::times_expression => { parse_binop(pair, Expr::NaturalTimes) }
Rule::equal_expression => { parse_binop(pair, Expr::BoolEQ) }
Rule::not_equal_expression => { parse_binop(pair, Expr::BoolNE) }
Rule::application_expression => { parse_binop(pair, Expr::App) }
Rule::selector_expression_raw =>
parse!(pair; (first: expression, rest*: str) => {
rest.fold_results(first, |acc, e| bx(Expr::Field(acc, e)))?
}),
Rule::identifier_raw =>
parse!(pair; (name: str, idx?: natural) => {
match Builtin::parse(name) {
Some(b) => bx(Expr::Builtin(b)),
None => match name {
"True" => bx(Expr::BoolLit(true)),
"False" => bx(Expr::BoolLit(false)),
name => bx(Expr::Var(V(name, idx.unwrap_or(0)))),
}
}
}),
Rule::ifthenelse_expression =>
parse!(pair; (cond: expression, left: expression, right: expression) => {
bx(Expr::BoolIf(cond, left, right))
}),
// Rule::record_type_or_literal => {
// let mut inner = pair.into_inner();
// let first_expr = parse_expression(inner.next().unwrap());
// inner.fold(first_expr, |acc, e| bx(Expr::Field(acc, e.as_str())))
// }
_ => {
let rulename = format!("{:?}", pair.as_rule());
parse!(pair; (exprs*: expression) => {
bx(Expr::FailedParse(rulename, exprs.map_results(|x| *x).collect::<ParseResult<_>>()?))
})
}
}
}
pub fn parse_expr_pest(s: &str) -> ParseResult<BoxExpr> {
let parsed_expr = DhallParser::parse(Rule::final_expression, s)?.next().unwrap();
parse_expression(parsed_expr)
}
#[test]
fn test_parse() {
use crate::core::Expr::*;
// let expr = r#"{ x = "foo", y = 4 }.x"#;
// let expr = r#"(1 + 2) * 3"#;
let expr = r#"if True then 1 + 3 * 5 else 2"#;
println!("{:?}", parse_expr_lalrpop(expr));
match parse_expr_pest(expr) {
Err(e) => {
println!("{:?}", e);
println!("{}", e);
},
ok => println!("{:?}", ok),
}
assert_eq!(parse_expr_pest(expr).unwrap(), parse_expr_lalrpop(expr).unwrap());
assert!(false);
println!("test {:?}", parse_expr_lalrpop("3 + 5 * 10"));
assert!(parse_expr_lalrpop("22").is_ok());
assert!(parse_expr_lalrpop("(22)").is_ok());
assert_eq!(parse_expr_lalrpop("3 + 5 * 10").ok(),
Some(Box::new(NaturalPlus(Box::new(NaturalLit(3)),
Box::new(NaturalTimes(Box::new(NaturalLit(5)),
Box::new(NaturalLit(10))))))));
// The original parser is apparently right-associative
assert_eq!(parse_expr_lalrpop("2 * 3 * 4").ok(),
Some(Box::new(NaturalTimes(Box::new(NaturalLit(2)),
Box::new(NaturalTimes(Box::new(NaturalLit(3)),
Box::new(NaturalLit(4))))))));
assert!(parse_expr_lalrpop("((((22))))").is_ok());
assert!(parse_expr_lalrpop("((22)").is_err());
println!("{:?}", parse_expr_lalrpop("\\(b : Bool) -> b == False"));
assert!(parse_expr_lalrpop("\\(b : Bool) -> b == False").is_ok());
println!("{:?}", parse_expr_lalrpop("foo.bar"));
assert!(parse_expr_lalrpop("foo.bar").is_ok());
assert!(parse_expr_lalrpop("[] : List Bool").is_ok());
// println!("{:?}", parse_expr_lalrpop("< Left = True | Right : Natural >"));
// println!("{:?}", parse_expr_lalrpop(r#""bl${42}ah""#));
// assert!(parse_expr_lalrpop("< Left = True | Right : Natural >").is_ok());
}
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