Refactor pratt parser

dust-lang/src/lex.rs

@@ -6,7 +6,6 @@
 use std::{
     error::Error,
     fmt::{self, Display, Formatter},
-    num::{ParseFloatError, ParseIntError},
 };
 
 use crate::{Span, Token};
@@ -24,9 +23,9 @@ use crate::{Span, Token};
 ///     [
 ///         (Token::Identifier("x"), (0, 1)),
 ///         (Token::Equal, (2, 3)),
-///         (Token::Integer(1), (4, 5)),
+///         (Token::Integer("1"), (4, 5)),
 ///         (Token::Plus, (6, 7)),
-///         (Token::Integer(2), (8, 9)),
+///         (Token::Integer("2"), (8, 9)),
 ///         (Token::Eof, (9, 9)),
 ///     ]
 /// );
@@ -77,9 +76,9 @@ pub fn lex<'chars, 'src: 'chars>(input: &'src str) -> Result<Vec<(Token<'chars>,
 ///     [
 ///         (Token::Identifier("x"), (0, 1)),
 ///         (Token::Equal, (2, 3)),
-///         (Token::Integer(1), (4, 5)),
+///         (Token::Integer("1"), (4, 5)),
 ///         (Token::Plus, (6, 7)),
-///         (Token::Integer(2), (8, 9)),
+///         (Token::Integer("2"), (8, 9)),
 ///         (Token::Eof, (9, 9)),
 ///     ]
 /// )
@@ -110,7 +109,7 @@ impl Lexer {
                         self.position += 9;
 
                         (
-                            Token::Float(f64::NEG_INFINITY),
+                            Token::Float("-Infinity"),
                             (self.position - 9, self.position),
                         )
                     } else {
@@ -231,6 +230,17 @@ impl Lexer {
 
                     (Token::Semicolon, (self.position - 1, self.position))
                 }
+                '|' => {
+                    if let Some('|') = self.peek_second_char(source) {
+                        self.position += 2;
+
+                        (Token::DoublePipe, (self.position - 2, self.position))
+                    } else {
+                        self.position += 1;
+
+                        return Err(LexError::UnexpectedCharacter(c));
+                    }
+                }
                 _ => {
                     self.position += 1;
 
@@ -244,6 +254,15 @@ impl Lexer {
         Ok((token, span))
     }
 
+    /// Peek at the next token without consuming the source.
+    pub fn peek_token<'src>(&mut self, source: &'src str) -> Result<(Token<'src>, Span), LexError> {
+        let token = self.next_token(source)?;
+
+        self.position -= token.0.as_str().len();
+
+        Ok(token)
+    }
+
     /// Progress to the next character.
     fn next_char(&mut self, source: &str) -> Option<char> {
         if let Some(c) = source[self.position..].chars().next() {
@@ -335,14 +354,12 @@ impl Lexer {
             }
         }
 
+        let text = &source[start_pos..self.position];
+
         if is_float {
-            let float = source[start_pos..self.position].parse::<f64>()?;
+            Ok((Token::Float(text), (start_pos, self.position)))
-
-            Ok((Token::Float(float), (start_pos, self.position)))
         } else {
-            let integer = source[start_pos..self.position].parse::<i64>()?;
+            Ok((Token::Integer(text), (start_pos, self.position)))
-
-            Ok((Token::Integer(integer), (start_pos, self.position)))
         }
     }
 
@@ -363,13 +380,13 @@ impl Lexer {
 
         let string = &source[start_pos..self.position];
         let token = match string {
-            "true" => Token::Boolean(true),
+            "true" => Token::Boolean("true"),
-            "false" => Token::Boolean(false),
+            "false" => Token::Boolean("false"),
-            "Infinity" => Token::Float(f64::INFINITY),
+            "Infinity" => Token::Float("Infinity"),
             "is_even" => Token::IsEven,
             "is_odd" => Token::IsOdd,
             "length" => Token::Length,
-            "NaN" => Token::Float(f64::NAN),
+            "NaN" => Token::Float("NaN"),
             "read_line" => Token::ReadLine,
             "write_line" => Token::WriteLine,
             _ => Token::Identifier(string),
@@ -410,16 +427,12 @@ impl Default for Lexer {
 
 #[derive(Debug, PartialEq, Clone)]
 pub enum LexError {
-    FloatError(ParseFloatError),
-    IntegerError(ParseIntError),
     UnexpectedCharacter(char),
 }
 
 impl Error for LexError {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         match self {
-            Self::FloatError(parse_float_error) => Some(parse_float_error),
-            Self::IntegerError(parse_int_error) => Some(parse_int_error),
             Self::UnexpectedCharacter(_) => None,
         }
     }
@@ -428,12 +441,6 @@ impl Error for LexError {
 impl Display for LexError {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
-            Self::FloatError(parse_float_error) => {
-                write!(f, "Failed to parse float: {}", parse_float_error)
-            }
-            Self::IntegerError(parse_int_error) => {
-                write!(f, "Failed to parse integer: {}", parse_int_error)
-            }
             Self::UnexpectedCharacter(character) => {
                 write!(f, "Unexpected character: '{}'", character)
             }
@@ -441,22 +448,25 @@ impl Display for LexError {
     }
 }
 
-impl From<ParseFloatError> for LexError {
-    fn from(error: std::num::ParseFloatError) -> Self {
-        Self::FloatError(error)
-    }
-}
-
-impl From<ParseIntError> for LexError {
-    fn from(error: std::num::ParseIntError) -> Self {
-        Self::IntegerError(error)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    #[test]
+    fn or() {
+        let input = "true || false";
+
+        assert_eq!(
+            lex(input),
+            Ok(vec![
+                (Token::Boolean("true"), (0, 4)),
+                (Token::DoublePipe, (5, 7)),
+                (Token::Boolean("false"), (8, 13)),
+                (Token::Eof, (13, 13)),
+            ])
+        )
+    }
+
     #[test]
     fn block() {
         let input = "{ x = 42; y = 'foobar' }";
@@ -467,7 +477,7 @@ mod tests {
                 (Token::LeftCurlyBrace, (0, 1)),
                 (Token::Identifier("x"), (2, 3)),
                 (Token::Equal, (4, 5)),
-                (Token::Integer(42), (6, 8)),
+                (Token::Integer("42"), (6, 8)),
                 (Token::Semicolon, (8, 9)),
                 (Token::Identifier("y"), (10, 11)),
                 (Token::Equal, (12, 13)),
@@ -485,9 +495,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(42), (0, 2)),
+                (Token::Integer("42"), (0, 2)),
                 (Token::DoubleEqual, (3, 5)),
-                (Token::Integer(42), (6, 8)),
+                (Token::Integer("42"), (6, 8)),
                 (Token::Eof, (8, 8)),
             ])
         )
@@ -500,9 +510,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(42), (0, 2)),
+                (Token::Integer("42"), (0, 2)),
                 (Token::Percent, (3, 4)),
-                (Token::Integer(2), (5, 6)),
+                (Token::Integer("2"), (5, 6)),
                 (Token::Eof, (6, 6)),
             ])
         )
@@ -515,9 +525,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(42), (0, 2)),
+                (Token::Integer("42"), (0, 2)),
                 (Token::Slash, (3, 4)),
-                (Token::Integer(2), (5, 6)),
+                (Token::Integer("2"), (5, 6)),
                 (Token::Eof, (6, 6)),
             ])
         )
@@ -533,7 +543,7 @@ mod tests {
                 (Token::LeftCurlyBrace, (0, 1)),
                 (Token::Identifier("x"), (2, 3)),
                 (Token::Equal, (4, 5)),
-                (Token::Integer(42), (6, 8)),
+                (Token::Integer("42"), (6, 8)),
                 (Token::Comma, (8, 9)),
                 (Token::Identifier("y"), (10, 11)),
                 (Token::Equal, (12, 13)),
@@ -591,7 +601,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Float(f64::INFINITY), (0, 8)),
+                (Token::Float("Infinity"), (0, 8)),
                 (Token::Eof, (8, 8)),
             ])
         )
@@ -604,7 +614,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Float(f64::NEG_INFINITY), (0, 9)),
+                (Token::Float("-Infinity"), (0, 9)),
                 (Token::Eof, (9, 9)),
             ])
         )
@@ -614,7 +624,7 @@ mod tests {
     fn nan() {
         let input = "NaN";
 
-        assert!(lex(input).is_ok_and(|tokens| tokens[0].0 == Token::Float(f64::NAN)));
+        assert!(lex(input).is_ok_and(|tokens| tokens[0].0 == Token::Float("NaN")));
     }
 
     #[test]
@@ -623,7 +633,10 @@ mod tests {
 
         assert_eq!(
             lex(input),
-            Ok(vec![(Token::Float(42.42e42), (0, 8)), (Token::Eof, (8, 8)),])
+            Ok(vec![
+                (Token::Float("42.42e42"), (0, 8)),
+                (Token::Eof, (8, 8)),
+            ])
         )
     }
 
@@ -634,7 +647,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(i64::MAX), (0, 19)),
+                (Token::Integer("9223372036854775807"), (0, 19)),
                 (Token::Eof, (19, 19)),
             ])
         )
@@ -647,7 +660,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(i64::MIN), (0, 20)),
+                (Token::Integer("-9223372036854775808"), (0, 20)),
                 (Token::Eof, (20, 20)),
             ])
         )
@@ -660,9 +673,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(-42), (0, 3)),
+                (Token::Integer("-42"), (0, 3)),
                 (Token::Minus, (4, 5)),
-                (Token::Integer(-42), (6, 9)),
+                (Token::Integer("-42"), (6, 9)),
                 (Token::Eof, (9, 9)),
             ])
         )
@@ -674,7 +687,7 @@ mod tests {
 
         assert_eq!(
             lex(input),
-            Ok(vec![(Token::Integer(-42), (0, 3)), (Token::Eof, (3, 3))])
+            Ok(vec![(Token::Integer("-42"), (0, 3)), (Token::Eof, (3, 3))])
         )
     }
 
@@ -743,7 +756,7 @@ mod tests {
 
         assert_eq!(
             lex(input),
-            Ok(vec![(Token::Boolean(true), (0, 4)), (Token::Eof, (4, 4)),])
+            Ok(vec![(Token::Boolean("true"), (0, 4)), (Token::Eof, (4, 4)),])
         )
     }
 
@@ -753,7 +766,10 @@ mod tests {
 
         assert_eq!(
             lex(input),
-            Ok(vec![(Token::Boolean(false), (0, 5)), (Token::Eof, (5, 5))])
+            Ok(vec![
+                (Token::Boolean("false"), (0, 5)),
+                (Token::Eof, (5, 5))
+            ])
         )
     }
 
@@ -764,7 +780,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(42), (0, 2)),
+                (Token::Integer("42"), (0, 2)),
                 (Token::Dot, (2, 3)),
                 (Token::IsEven, (3, 10)),
                 (Token::LeftParenthesis, (10, 11)),
@@ -811,7 +827,7 @@ mod tests {
 
         assert_eq!(
             lex(input),
-            Ok(vec![(Token::Float(1.23), (0, 4)), (Token::Eof, (4, 4)),])
+            Ok(vec![(Token::Float("1.23"), (0, 4)), (Token::Eof, (4, 4)),])
         )
     }
 
@@ -823,7 +839,7 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Float(123456789.123456789), (0, 19)),
+                (Token::Float("123456789.123456789"), (0, 19)),
                 (Token::Eof, (19, 19)),
             ])
         )
@@ -836,9 +852,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(1), (0, 1)),
+                (Token::Integer("1"), (0, 1)),
                 (Token::Plus, (2, 3)),
-                (Token::Integer(2), (4, 5)),
+                (Token::Integer("2"), (4, 5)),
                 (Token::Eof, (5, 5)),
             ])
         )
@@ -851,9 +867,9 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(1), (0, 1)),
+                (Token::Integer("1"), (0, 1)),
                 (Token::Star, (2, 3)),
-                (Token::Integer(2), (4, 5)),
+                (Token::Integer("2"), (4, 5)),
                 (Token::Eof, (5, 5)),
             ])
         )
@@ -866,11 +882,11 @@ mod tests {
         assert_eq!(
             lex(input),
             Ok(vec![
-                (Token::Integer(1), (0, 1)),
+                (Token::Integer("1"), (0, 1)),
                 (Token::Plus, (2, 3)),
-                (Token::Integer(2), (4, 5)),
+                (Token::Integer("2"), (4, 5)),
                 (Token::Star, (6, 7)),
-                (Token::Integer(3), (8, 9)),
+                (Token::Integer("3"), (8, 9)),
                 (Token::Eof, (9, 9)),
             ])
         );
@@ -885,11 +901,11 @@ mod tests {
             Ok(vec![
                 (Token::Identifier("a"), (0, 1)),
                 (Token::Equal, (2, 3)),
-                (Token::Integer(1), (4, 5)),
+                (Token::Integer("1"), (4, 5)),
                 (Token::Plus, (6, 7)),
-                (Token::Integer(2), (8, 9)),
+                (Token::Integer("2"), (8, 9)),
                 (Token::Star, (10, 11)),
-                (Token::Integer(3), (12, 13)),
+                (Token::Integer("3"), (12, 13)),
                 (Token::Eof, (13, 13)),
             ])
         );

dust-lang/src/parse.rs

@@ -7,6 +7,8 @@ use std::{
     collections::VecDeque,
     error::Error,
     fmt::{self, Display, Formatter},
+    num::{ParseFloatError, ParseIntError},
+    str::ParseBoolError,
 };
 
 use crate::{
@@ -150,243 +152,54 @@ impl<'src> Parser<'src> {
     }
 
     fn parse_node(&mut self, precedence: u8) -> Result<Node<Statement>, ParseError> {
-        let left_node = self.parse_primary()?;
+        let left = self.parse_primary()?;
-        let left_start = left_node.position.0;
 
         if precedence < self.current_precedence() {
-            match &self.current {
+            self.parse_infix(left)
-                (Token::Dot, _) => {
+        } else {
-                    self.next_token()?;
+            Ok(left)
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::PropertyAccess(Box::new(left_node), Box::new(right_node)),
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::DoubleAmpersand, _) => {
-                    let operator = Node::new(BinaryOperator::And, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::DoubleEqual, _) => {
-                    let operator = Node::new(BinaryOperator::Equal, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Greater, _) => {
-                    let operator = Node::new(BinaryOperator::Greater, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::GreaterEqual, _) => {
-                    let operator = Node::new(BinaryOperator::GreaterOrEqual, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Less, _) => {
-                    let operator = Node::new(BinaryOperator::Less, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::LessEqual, _) => {
-                    let operator = Node::new(BinaryOperator::LessOrEqual, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Minus, _) => {
-                    let operator = Node::new(BinaryOperator::Subtract, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Plus, _) => {
-                    let operator = Node::new(BinaryOperator::Add, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Semicolon, (_, right_end)) => {
-                    return Ok(Node::new(
-                        Statement::Nil(Box::new(left_node)),
-                        (left_start, *right_end),
-                    ))
-                }
-                (Token::Star, _) => {
-                    let operator = Node::new(BinaryOperator::Multiply, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Slash, _) => {
-                    let operator = Node::new(BinaryOperator::Divide, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                (Token::Percent, _) => {
-                    let operator = Node::new(BinaryOperator::Modulo, self.current.1);
-
-                    self.next_token()?;
-
-                    let right_node = self.parse_node(self.current_precedence())?;
-                    let right_end = right_node.position.1;
-
-                    return Ok(Node::new(
-                        Statement::BinaryOperation {
-                            left: Box::new(left_node),
-                            operator,
-                            right: Box::new(right_node),
-                        },
-                        (left_start, right_end),
-                    ));
-                }
-                _ => {}
-            }
         }
-
-        Ok(left_node)
     }
 
     fn parse_primary(&mut self) -> Result<Node<Statement>, ParseError> {
         match self.current {
-            (Token::Boolean(boolean), span) => {
+            (Token::Boolean(text), position) => {
                 self.next_token()?;
 
+                let boolean = text
+                    .parse()
+                    .map_err(|error| ParseError::BooleanError { error, position })?;
+
                 Ok(Node::new(
                     Statement::Constant(Value::boolean(boolean)),
-                    span,
+                    position,
                 ))
             }
-            (Token::Float(float), span) => {
+            (Token::Float(text), position) => {
                 self.next_token()?;
 
-                Ok(Node::new(Statement::Constant(Value::float(float)), span))
+                let float = text
+                    .parse()
+                    .map_err(|error| ParseError::FloatError { error, position })?;
+
+                Ok(Node::new(
+                    Statement::Constant(Value::float(float)),
+                    position,
+                ))
             }
-            (Token::Integer(int), span) => {
+            (Token::Integer(text), position) => {
                 self.next_token()?;
 
-                Ok(Node::new(Statement::Constant(Value::integer(int)), span))
+                let integer = text
+                    .parse()
+                    .map_err(|error| ParseError::IntegerError { error, position })?;
+
+                Ok(Node::new(
+                    Statement::Constant(Value::integer(integer)),
+                    position,
+                ))
             }
-            (Token::Identifier(text), span) => {
+            (Token::Identifier(text), position) => {
                 self.next_token()?;
 
                 if let (Token::Equal, _) = self.current {
@@ -397,33 +210,36 @@ impl<'src> Parser<'src> {
 
                     Ok(Node::new(
                         Statement::Assignment {
-                            identifier: Node::new(Identifier::new(text), span),
+                            identifier: Node::new(Identifier::new(text), position),
                             value_node: Box::new(value_node),
                         },
-                        (span.0, right_end),
+                        (position.0, right_end),
                     ))
                 } else {
                     Ok(Node::new(
                         Statement::Identifier(Identifier::new(text)),
-                        span,
+                        position,
                     ))
                 }
             }
-            (Token::String(string), span) => {
+            (Token::String(string), position) => {
                 self.next_token()?;
 
-                Ok(Node::new(Statement::Constant(Value::string(string)), span))
+                Ok(Node::new(
+                    Statement::Constant(Value::string(string)),
+                    position,
+                ))
             }
-            (Token::LeftCurlyBrace, left_span) => {
+            (Token::LeftCurlyBrace, left_position) => {
                 self.next_token()?;
 
                 // If the next token is a right curly brace, this is an empty map
-                if let (Token::RightCurlyBrace, right_span) = self.current {
+                if let (Token::RightCurlyBrace, right_position) = self.current {
                     self.next_token()?;
 
                     return Ok(Node::new(
                         Statement::Map(Vec::new()),
-                        (left_span.0, right_span.1),
+                        (left_position.0, right_position.1),
                     ));
                 }
 
@@ -431,10 +247,13 @@ impl<'src> Parser<'src> {
 
                 loop {
                     // If a closing brace is found, return the new statement
-                    if let (Token::RightCurlyBrace, right_span) = self.current {
+                    if let (Token::RightCurlyBrace, right_position) = self.current {
                         self.next_token()?;
 
-                        return Ok(Node::new(statement.unwrap(), (left_span.0, right_span.1)));
+                        return Ok(Node::new(
+                            statement.unwrap(),
+                            (left_position.0, right_position.1),
+                        ));
                     }
 
                     let next_node = self.parse_node(0)?;
@@ -503,15 +322,15 @@ impl<'src> Parser<'src> {
                     }
                 }
             }
-            (Token::LeftParenthesis, left_span) => {
+            (Token::LeftParenthesis, left_position) => {
                 self.next_token()?;
 
                 let node = self.parse_node(0)?;
 
-                if let (Token::RightParenthesis, right_span) = self.current {
+                if let (Token::RightParenthesis, right_position) = self.current {
                     self.next_token()?;
 
-                    Ok(Node::new(node.inner, (left_span.0, right_span.1)))
+                    Ok(Node::new(node.inner, (left_position.0, right_position.1)))
                 } else {
                     Err(ParseError::ExpectedToken {
                         expected: TokenOwned::RightParenthesis,
@@ -520,18 +339,18 @@ impl<'src> Parser<'src> {
                     })
                 }
             }
-            (Token::LeftSquareBrace, left_span) => {
+            (Token::LeftSquareBrace, left_position) => {
                 self.next_token()?;
 
                 let mut nodes = Vec::new();
 
                 loop {
-                    if let (Token::RightSquareBrace, right_span) = self.current {
+                    if let (Token::RightSquareBrace, right_position) = self.current {
                         self.next_token()?;
 
                         return Ok(Node::new(
                             Statement::List(nodes),
-                            (left_span.0, right_span.1),
+                            (left_position.0, right_position.1),
                         ));
                     }
 
@@ -554,7 +373,7 @@ impl<'src> Parser<'src> {
             }
             (
                 Token::IsEven | Token::IsOdd | Token::Length | Token::ReadLine | Token::WriteLine,
-                left_span,
+                left_position,
             ) => {
                 let function = match self.current.0 {
                     Token::IsEven => BuiltInFunction::IsEven,
@@ -611,7 +430,7 @@ impl<'src> Parser<'src> {
                         type_arguments: None,
                         value_arguments,
                     },
-                    left_span,
+                    left_position,
                 ))
             }
             _ => Err(ParseError::UnexpectedToken {
@@ -621,10 +440,62 @@ impl<'src> Parser<'src> {
         }
     }
 
+    fn parse_infix(&mut self, left: Node<Statement>) -> Result<Node<Statement>, ParseError> {
+        let left_start = left.position.0;
+
+        let binary_operator = match &self.current {
+            (Token::Dot, _) => {
+                self.next_token()?;
+
+                let right_node = self.parse_node(0)?;
+                let right_end = right_node.position.1;
+
+                return Ok(Node::new(
+                    Statement::PropertyAccess(Box::new(left), Box::new(right_node)),
+                    (left_start, right_end),
+                ));
+            }
+            (Token::DoubleAmpersand, _) => Node::new(BinaryOperator::And, self.current.1),
+            (Token::DoubleEqual, _) => Node::new(BinaryOperator::Equal, self.current.1),
+            (Token::DoublePipe, _) => Node::new(BinaryOperator::Or, self.current.1),
+            (Token::Greater, _) => Node::new(BinaryOperator::Greater, self.current.1),
+            (Token::GreaterEqual, _) => Node::new(BinaryOperator::GreaterOrEqual, self.current.1),
+            (Token::Less, _) => Node::new(BinaryOperator::Less, self.current.1),
+            (Token::LessEqual, _) => Node::new(BinaryOperator::LessOrEqual, self.current.1),
+            (Token::Minus, _) => Node::new(BinaryOperator::Subtract, self.current.1),
+            (Token::Plus, _) => Node::new(BinaryOperator::Add, self.current.1),
+            (Token::Star, _) => Node::new(BinaryOperator::Multiply, self.current.1),
+            (Token::Slash, _) => Node::new(BinaryOperator::Divide, self.current.1),
+            (Token::Percent, _) => Node::new(BinaryOperator::Modulo, self.current.1),
+            _ => {
+                self.next_token()?;
+
+                return Err(ParseError::UnexpectedToken {
+                    actual: self.current.0.to_owned(),
+                    position: self.current.1,
+                });
+            }
+        };
+
+        self.next_token()?;
+
+        let right = self.parse_node(0)?;
+        let right_end = right.position.1;
+
+        Ok(Node::new(
+            Statement::BinaryOperation {
+                left: Box::new(left),
+                operator: binary_operator,
+                right: Box::new(right),
+            },
+            (left_start, right_end),
+        ))
+    }
+
     fn current_precedence(&self) -> u8 {
         match self.current.0 {
             Token::DoubleEqual => 7,
-            Token::DoubleAmpersand => 6,
+            Token::DoubleAmpersand | Token::DoublePipe => 6,
             Token::Greater | Token::GreaterEqual | Token::Less | Token::LessEqual => 5,
             Token::Dot => 4,
             Token::Percent => 3,
@@ -639,6 +510,10 @@ impl<'src> Parser<'src> {
 
 #[derive(Debug, PartialEq, Clone)]
 pub enum ParseError {
+    BooleanError {
+        error: ParseBoolError,
+        position: Span,
+    },
     LexError {
         error: LexError,
         position: Span,
@@ -656,15 +531,26 @@ pub enum ParseError {
         actual: TokenOwned,
         position: Span,
     },
+    FloatError {
+        error: ParseFloatError,
+        position: Span,
+    },
+    IntegerError {
+        error: ParseIntError,
+        position: Span,
+    },
 }
 
 impl ParseError {
     pub fn position(&self) -> Span {
         match self {
-            Self::LexError { position, .. } => *position,
+            ParseError::BooleanError { position, .. } => *position,
-            Self::ExpectedIdentifier { position, .. } => *position,
+            ParseError::ExpectedIdentifier { position, .. } => *position,
-            Self::ExpectedToken { position, .. } => *position,
+            ParseError::ExpectedToken { position, .. } => *position,
-            Self::UnexpectedToken { position, .. } => *position,
+            ParseError::FloatError { position, .. } => *position,
+            ParseError::IntegerError { position, .. } => *position,
+            ParseError::LexError { position, .. } => *position,
+            ParseError::UnexpectedToken { position, .. } => *position,
         }
     }
 }
@@ -681,13 +567,16 @@ impl Error for ParseError {
 impl Display for ParseError {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
-            Self::LexError { error, .. } => write!(f, "{}", error),
+            Self::BooleanError { error, .. } => write!(f, "{}", error),
             Self::ExpectedIdentifier { actual, .. } => {
                 write!(f, "Expected identifier, found {actual}")
             }
             Self::ExpectedToken {
                 expected, actual, ..
             } => write!(f, "Expected token {expected}, found {actual}"),
+            Self::FloatError { error, .. } => write!(f, "{}", error),
+            Self::IntegerError { error, .. } => write!(f, "{}", error),
+            Self::LexError { error, .. } => write!(f, "{}", error),
             Self::UnexpectedToken { actual, .. } => write!(f, "Unexpected token {actual}"),
         }
     }
@@ -699,6 +588,32 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn or() {
+        let input = "true || false";
+
+        assert_eq!(
+            parse(input),
+            Ok(AbstractSyntaxTree {
+                nodes: [Node::new(
+                    Statement::BinaryOperation {
+                        left: Box::new(Node::new(
+                            Statement::Constant(Value::boolean(true)),
+                            (0, 4)
+                        )),
+                        operator: Node::new(BinaryOperator::Or, (5, 7)),
+                        right: Box::new(Node::new(
+                            Statement::Constant(Value::boolean(false)),
+                            (8, 13)
+                        )),
+                    },
+                    (0, 13)
+                )]
+                .into()
+            })
+        );
+    }
+
     #[test]
     fn misplaced_semicolon() {
         let input = ";";

dust-lang/src/token.rs

@@ -11,9 +11,9 @@ pub enum Token<'src> {
     Identifier(&'src str),
 
     // Hard-coded values
-    Boolean(bool),
+    Boolean(&'src str),
-    Float(f64),
+    Float(&'src str),
-    Integer(i64),
+    Integer(&'src str),
     String(&'src str),
 
     // Keywords
@@ -51,7 +51,7 @@ pub enum Token<'src> {
 impl<'src> Token<'src> {
     pub fn to_owned(&self) -> TokenOwned {
         match self {
-            Token::Boolean(boolean) => TokenOwned::Boolean(*boolean),
+            Token::Boolean(boolean) => TokenOwned::Boolean(boolean.to_string()),
             Token::Comma => TokenOwned::Comma,
             Token::Dot => TokenOwned::Dot,
             Token::DoubleAmpersand => TokenOwned::DoubleAmpersand,
@@ -59,11 +59,11 @@ impl<'src> Token<'src> {
             Token::DoublePipe => TokenOwned::DoublePipe,
             Token::Eof => TokenOwned::Eof,
             Token::Equal => TokenOwned::Equal,
-            Token::Float(float) => TokenOwned::Float(*float),
+            Token::Float(float) => TokenOwned::Float(float.to_string()),
             Token::Greater => TokenOwned::Greater,
             Token::GreaterEqual => TokenOwned::GreaterOrEqual,
             Token::Identifier(text) => TokenOwned::Identifier(text.to_string()),
-            Token::Integer(integer) => TokenOwned::Integer(*integer),
+            Token::Integer(integer) => TokenOwned::Integer(integer.to_string()),
             Token::IsEven => TokenOwned::IsEven,
             Token::IsOdd => TokenOwned::IsOdd,
             Token::LeftCurlyBrace => TokenOwned::LeftCurlyBrace,
@@ -87,9 +87,11 @@ impl<'src> Token<'src> {
         }
     }
 
-    pub fn as_str(&self) -> &'static str {
+    pub fn as_str(&self) -> &str {
         match self {
-            Token::Boolean(_) => "boolean",
+            Token::Boolean(boolean_text) => boolean_text,
+            Token::Identifier(text) => text,
+            Token::Integer(integer_text) => integer_text,
             Token::Comma => ",",
             Token::Dot => ".",
             Token::DoubleAmpersand => "&&",
@@ -100,8 +102,6 @@ impl<'src> Token<'src> {
             Token::Float(_) => "float",
             Token::Greater => ">",
             Token::GreaterEqual => ">=",
-            Token::Identifier(_) => "identifier",
-            Token::Integer(_) => "integer",
             Token::IsEven => "is_even",
             Token::IsOdd => "is_odd",
             Token::LeftCurlyBrace => "{",
@@ -128,17 +128,13 @@ impl<'src> Token<'src> {
 
 impl<'src> Display for Token<'src> {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.write_str(self.as_str())
+        write!(f, "{}", self.as_str())
     }
 }
 
 impl<'src> PartialEq for Token<'src> {
     fn eq(&self, other: &Self) -> bool {
         match (self, other) {
-            // Floats are compared by their bit representation.
-            (Token::Float(left), Token::Float(right)) => left.to_bits() == right.to_bits(),
-
-            // Compare all other variants normally.
             (Token::Boolean(left), Token::Boolean(right)) => left == right,
             (Token::Comma, Token::Comma) => true,
             (Token::Dot, Token::Dot) => true,
@@ -147,6 +143,7 @@ impl<'src> PartialEq for Token<'src> {
             (Token::DoublePipe, Token::DoublePipe) => true,
             (Token::Eof, Token::Eof) => true,
             (Token::Equal, Token::Equal) => true,
+            (Token::Float(left), Token::Float(right)) => left == right,
             (Token::Greater, Token::Greater) => true,
             (Token::GreaterEqual, Token::GreaterEqual) => true,
             (Token::Identifier(left), Token::Identifier(right)) => left == right,
@@ -186,9 +183,9 @@ pub enum TokenOwned {
     Identifier(String),
 
     // Hard-coded values
-    Boolean(bool),
+    Boolean(String),
-    Float(f64),
+    Float(String),
-    Integer(i64),
+    Integer(String),
     String(String),
 
     // Keywords

dust-lang/src/vm.rs

@@ -448,6 +448,16 @@ impl Display for VmError {
 mod tests {
     use super::*;
 
+    #[test]
+    fn or() {
+        let input = "true || false";
+
+        assert_eq!(
+            run(input, &mut HashMap::new()),
+            Ok(Some(Value::boolean(true)))
+        );
+    }
+
     #[test]
     fn map_equal() {
         let input = "{ y = 'foo', } == { y = 'foo', }";