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Fine-tune pratt parsing to support more complexity

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This commit is contained in:
Jeff 2024-08-12 08:35:08 -04:00
parent c56a187d05
commit bf11bd1f0f
2 changed files with 37 additions and 23 deletions
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4
dust-lang/src/analyzer.rs
View File

@ -126,6 +126,10 @@ impl<'a> Analyzer<'a> {
actual: right.as_ref().clone(),
});
}
} else {
return Err(AnalyzerError::ExpectedValue {
actual: left.as_ref().clone(),
});
}
}
}

34
dust-lang/src/parser.rs
View File

@ -147,13 +147,19 @@ impl<'src> Parser<'src> {
Ok(())
}
fn parse_statement(&mut self, precedence: u8) -> Result<Node<Statement>, ParseError> {
fn parse_statement(&mut self, mut precedence: u8) -> Result<Node<Statement>, ParseError> {
// Parse a statement starting from the current node.
let mut left = self.parse_prefix()?;
// While the current token has a higher precedence than the given precedence
while precedence < self.current.0.precedence() {
// Give precedence to postfix operations
if self.current.0.is_postfix() {
left = self.parse_postfix(left)?;
// Replace the left-hand side with the postfix operation and use the postfix
// operator's precedence to determine if the loop should continue
(left, precedence) = self.parse_postfix(left)?;
} else {
// Replace the left-hand side with the infix operation
left = self.parse_infix(left)?;
}
}
@ -586,7 +592,7 @@ impl<'src> Parser<'src> {
if let Token::Dot = &self.current.0 {
self.next_token()?;
let right = self.parse_statement(Token::Dot.precedence() + 1)?;
let right = self.parse_statement(0)?;
let right_end = right.position.1;
if let Statement::BuiltInFunctionCall {
@ -688,17 +694,18 @@ impl<'src> Parser<'src> {
))
}
fn parse_postfix(&mut self, left: Node<Statement>) -> Result<Node<Statement>, ParseError> {
fn parse_postfix(
&mut self,
left: Node<Statement>,
) -> Result<(Node<Statement>, u8), ParseError> {
if let Token::Semicolon = &self.current.0 {
self.next_token()?;
let left_start = left.position.0;
let operator_end = self.current.1 .1;
let node = Node::new(Statement::Nil(Box::new(left)), (left_start, operator_end));
Ok(Node::new(
Statement::Nil(Box::new(left)),
(left_start, operator_end),
))
Ok((node, self.current.0.precedence()))
} else {
Err(ParseError::UnexpectedToken {
actual: self.current.0.to_owned(),
@ -843,6 +850,7 @@ mod tests {
Ok(AbstractSyntaxTree {
nodes: [
Node::new(
Statement::Nil(Box::new(Node::new(
Statement::BinaryOperation {
left: Box::new(Node::new(
Statement::Identifier(Identifier::new("a")),
@ -854,17 +862,19 @@ mod tests {
(4, 5)
)),
},
(6, 7)
(0, 5)
))),
(0, 8)
),
Node::new(
Statement::UnaryOperation {
operator: Node::new(UnaryOperator::Negate, (0, 1)),
operator: Node::new(UnaryOperator::Negate, (7, 8)),
operand: Box::new(Node::new(
Statement::Identifier(Identifier::new("a")),
(7, 8)
(8, 9)
)),
},
(4, 8)
(7, 9)
)
]
.into()