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use crate::{
ast,
expr::UntypedExpr,
parser::{
error::{self, ParseError},
token::Token,
},
};
use chumsky::prelude::*;
pub fn parser(
r: Recursive<'_, Token, UntypedExpr, ParseError>,
) -> impl Parser<Token, UntypedExpr, Error = ParseError> + '_ {
choice((
select! {Token::Name { name } => name}
.map_with_span(|module, span: ast::Span| (module, span))
.then_ignore(just(Token::Dot))
.or_not()
.then(
select! {Token::UpName { name } => name}
.map_with_span(|name, span| (name, span))
.then_ignore(just(Token::Dot))
.or_not(),
)
.then(select! {Token::UpName { name } => name}.map_with_span(|name, span| (name, span)))
.then(
choice((
select! {Token::Name {name} => name}
.then_ignore(just(Token::Colon))
.then(choice((
r.clone(),
choice((select! {Token::DiscardName {name} => name }.map_with_span(
|name, span| UntypedExpr::Var {
location: span,
name,
},
),)),
)))
.map_with_span(|(label, value), span| ast::CallArg {
location: span,
value: Some(value),
label: Some(label),
}),
choice((
select! {Token::Name {name} => name}.map_with_span(|name, span| {
(
UntypedExpr::Var {
name: name.clone(),
location: span,
},
name,
)
}),
select! {Token::DiscardName {name} => name }.validate(
|name, span, emit| {
emit(ParseError::expected_input_found(
span,
None,
Some(error::Pattern::Discard),
));
(
UntypedExpr::Var {
location: span,
name: ast::CAPTURE_VARIABLE.to_string(),
},
name,
)
},
),
))
// NOTE: There's an ambiguity when the record shorthand syntax is used
// from within an if-else statement in the case of single-variable if-branch.
//
// For example, imagine the following:
//
// ```
// if season == Summer {
// foo
// } else {
// bar
// }
// ```
//
// Without that next odd parser combinator, the parser would parse:
//
// ```
// if season == Summer { foo }
// else {
// bar
// }
// ```
//
// And immediately choke on the next `else` because the if-branch body has
// already been consumed and interpreted as a record definition. So the next
// combinator ensures that we give priority back to an if-then statement rather
// than to the record definition.
.then_ignore(
just(Token::RightBrace)
.ignore_then(just(Token::Else))
.not()
.rewind(),
)
.map(|(value, name)| ast::CallArg {
location: value.location(),
value: Some(value),
label: Some(name),
}),
))
.separated_by(just(Token::Comma))
.allow_trailing()
.delimited_by(just(Token::LeftBrace), just(Token::RightBrace)),
),
select! {Token::Name { name } => name}
.map_with_span(|module, span| (module, span))
.then_ignore(just(Token::Dot))
.or_not()
.then(
select! {Token::UpName { name } => name}
.map_with_span(|name, span| (name, span))
.then_ignore(just(Token::Dot))
.or_not(),
)
.then(select! {Token::UpName { name } => name}.map_with_span(|name, span| (name, span)))
.then(
select! {Token::Name {name} => name}
.ignored()
.then_ignore(just(Token::Colon))
.validate(|_label, span, emit| {
emit(ParseError::expected_input_found(
span,
None,
Some(error::Pattern::Label),
))
})
.or_not()
.then(choice((
r.clone(),
select! {Token::DiscardName {name} => name }.map_with_span(|name, span| {
UntypedExpr::Var {
location: span,
name,
}
}),
)))
.map(|(_label, value)| ast::CallArg {
location: value.location(),
value: Some(value),
label: None,
})
.separated_by(just(Token::Comma))
.allow_trailing()
.delimited_by(just(Token::LeftParen), just(Token::RightParen)),
),
))
.map_with_span(
|(((module, namespace), (label, label_span)), arguments), span| {
let fun = match (module, namespace) {
(Some((module, module_span)), Some((namespace, namespace_span))) => {
UntypedExpr::FieldAccess {
location: module_span.union(namespace_span).union(label_span),
label,
container: Box::new(UntypedExpr::FieldAccess {
location: module_span.union(namespace_span),
label: namespace,
container: Box::new(UntypedExpr::Var {
location: module_span,
name: module,
}),
}),
}
}
(None, Some((namespace, namespace_span))) => UntypedExpr::FieldAccess {
location: namespace_span.union(label_span),
label,
container: Box::new(UntypedExpr::Var {
location: namespace_span,
name: namespace,
}),
},
(Some((module, module_span)), None) => UntypedExpr::FieldAccess {
location: module_span.union(label_span),
label,
container: Box::new(UntypedExpr::Var {
location: module_span,
name: module,
}),
},
(None, None) => UntypedExpr::Var {
location: label_span,
name: label,
},
};
fun.call(arguments, span)
},
)
}
#[cfg(test)]
mod tests {
use crate::assert_expr;
#[test]
fn record_enum() {
assert_expr!(r#"Winter"#);
}
#[test]
fn record_create_labeled() {
assert_expr!(r#"User { name: "Aiken", age, thing: 2 }"#);
}
#[test]
fn record_create_labeled_with_field_access() {
assert_expr!(r#"some_module.User { name: "Aiken", age, thing: 2 }"#);
}
#[test]
fn record_create_unlabeled() {
assert_expr!(r#"some_module.Thing(1, a)"#);
}
}