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Allow chaining of indexing (one level) and dotting.

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Stephen Chung
2020-03-07 22:50:46 +08:00
parent df6950f8f7
commit eed7bef974
3 changed files with 178 additions and 74 deletions
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49
src/parser.rs
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@@ -1275,47 +1275,34 @@ fn parse_unary<'a>(input: &mut Peekable<TokenIterator<'a>>) -> Result<Expr, Pars
}
fn parse_assignment(lhs: Expr, rhs: Expr, pos: Position) -> Result<Expr, ParseError> {
//println!("{:?} = {:?}", lhs, rhs);
fn all_dots(expr: &Expr) -> (bool, Position) {
fn valid_assignment_chain(expr: &Expr) -> (bool, Position) {
match expr {
Expr::Identifier(_, pos) => (true, *pos),
Expr::Index(idx_lhs, _, _) => match idx_lhs.as_ref() {
Expr::Identifier(_, _) => (true, idx_lhs.position()),
_ => (false, idx_lhs.position()),
},
Expr::Dot(dot_lhs, dot_rhs, _) => match dot_lhs.as_ref() {
Expr::Identifier(_, _) => all_dots(dot_rhs),
Expr::Identifier(_, _) => valid_assignment_chain(dot_rhs),
Expr::Index(idx_lhs, _, _) => match idx_lhs.as_ref() {
Expr::Identifier(_, _) => valid_assignment_chain(dot_rhs),
_ => (false, idx_lhs.position()),
},
_ => (false, dot_lhs.position()),
},
_ => (false, expr.position()),
}
}
match &lhs {
Expr::Identifier(_, _) => return Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos)),
Expr::Index(idx_lhs, _, _) => match idx_lhs.as_ref() {
Expr::Identifier(_, _) => {
return Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos))
}
_ => (),
},
Expr::Dot(dot_lhs, dot_rhs, _) => match dot_lhs.as_ref() {
Expr::Identifier(_, _) => match all_dots(&lhs) {
(true, _) => return Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos)),
(false, pos) => return Err(ParseError::new(PERR::AssignmentToInvalidLHS, pos)),
},
Expr::Index(idx_lhs, _, _) => match idx_lhs.as_ref() {
Expr::Identifier(_, _) => match all_dots(&dot_rhs) {
(true, _) => return Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos)),
(false, pos) => return Err(ParseError::new(PERR::AssignmentToInvalidLHS, pos)),
},
_ => (),
},
_ => (),
},
_ => (),
}
//println!("{:?} = {:?}", lhs, rhs);
return Err(ParseError::new(
PERR::AssignmentToInvalidLHS,
lhs.position(),
));
match valid_assignment_chain(&lhs) {
(true, _) => Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos)),
(false, pos) => Err(ParseError::new(PERR::AssignmentToInvalidLHS, pos)),
}
}
fn parse_op_assignment(