Parse expressions

Cargo.toml

@@ -14,4 +14,4 @@ opt-level = 3
 
 [dependencies]
 ariadne = "0.4.0"
-chumsky = "1.0.0-alpha.6"
+chumsky = { version = "1.0.0-alpha.6", features = ["pratt"] }

src/lib.rs

@@ -4,7 +4,7 @@ use std::{
     ops::Range,
 };
 
-use chumsky::{prelude::*, Parser};
+use chumsky::{pratt::*, prelude::*, Parser};
 
 #[derive(Clone, Debug, PartialEq)]
 pub enum Statement {
@@ -32,22 +32,15 @@ pub enum Expression {
 }
 
 #[derive(Clone, Debug, PartialEq)]
-pub struct Logic {
+pub enum Logic {
-    left: Expression,
+    Equal(Expression, Expression),
-    operator: LogicOperator,
+    NotEqual(Expression, Expression),
-    right: Expression,
+    Greater(Expression, Expression),
-}
+    Less(Expression, Expression),
-
+    GreaterOrEqual(Expression, Expression),
-#[derive(Clone, Debug, PartialEq)]
+    LessOrEqual(Expression, Expression),
-pub enum LogicOperator {
+    And(Expression, Expression),
-    Equal,
+    Or(Expression, Expression),
-    NotEqual,
-    Greater,
-    Less,
-    GreaterOrEqual,
-    LessOrEqual,
-    And,
-    Or,
 }
 
 #[derive(Clone, Debug, PartialEq)]
@@ -84,7 +77,9 @@ impl Display for Value {
     }
 }
 
-pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement> {
+pub fn parser<'src>() -> impl Parser<'src, &'src str, Expression> {
+    let operator = |text| just(text).padded();
+
     let value = recursive(|value| {
         let boolean = just("true")
             .or(just("false"))
@@ -102,24 +97,22 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement> {
 
         let float = choice((float_numeric, float_other));
 
-        let integer = just('-').or_not().then(text::int(10).padded()).map(
+        let integer = just('-')
-            |(negative, integer_text): (Option<char>, &str)| {
+            .or_not()
-                let integer = integer_text.parse::<i64>().unwrap();
+            .then(text::int(10).padded())
+            .to_slice()
+            .map(|text: &str| {
+                let integer = text.parse::<i64>().unwrap();
 
-                if negative.is_some() {
+                Value::Integer(integer)
-                    Value::Integer(-integer)
+            });
-                } else {
-                    Value::Integer(integer)
-                }
-            },
-        );
 
         let delimited_string = |delimiter| {
             just(delimiter)
                 .ignore_then(none_of(delimiter).repeated())
                 .then_ignore(just(delimiter))
                 .to_slice()
-                .map(|text: &str| Value::String(text.to_string()))
+                .map(|text: &str| Value::String(text[1..text.len() - 1].to_string()))
         };
 
         let string = choice((
@@ -140,52 +133,36 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement> {
         choice((boolean, float, integer, string, list))
     });
 
-    let expression = recursive(|expression| {
+    let value_expression = value.map(|value| Expression::Value(value));
-        let logic = expression
-            .clone()
-            .then(choice((
-                just("==").to(LogicOperator::Equal),
-                just("!=").to(LogicOperator::NotEqual),
-                just(">").to(LogicOperator::Greater),
-                just("<").to(LogicOperator::Less),
-                just(">=").to(LogicOperator::GreaterOrEqual),
-                just("<=").to(LogicOperator::LessOrEqual),
-                just("&&").to(LogicOperator::And),
-                just("||").to(LogicOperator::Or),
-            )))
-            .padded()
-            .then(expression)
-            .map(|((left, operator), right)| {
-                Expression::Logic(Box::new(Logic {
-                    left,
-                    operator,
-                    right,
-                }))
-            });
 
-        let value = value.map(|value| Expression::Value(value));
+    let logic_expression = value_expression.pratt((
+        infix(left(1), operator("=="), |left, right| {
+            Expression::Logic(Box::new(Logic::Equal(left, right)))
+        }),
+        infix(left(1), operator("!="), |left, right| {
+            Expression::Logic(Box::new(Logic::NotEqual(left, right)))
+        }),
+        infix(left(1), operator(">"), |left, right| {
+            Expression::Logic(Box::new(Logic::Greater(left, right)))
+        }),
+        infix(left(1), operator("<"), |left, right| {
+            Expression::Logic(Box::new(Logic::Less(left, right)))
+        }),
+        infix(left(1), operator(">="), |left, right| {
+            Expression::Logic(Box::new(Logic::GreaterOrEqual(left, right)))
+        }),
+        infix(left(1), operator("<="), |left, right| {
+            Expression::Logic(Box::new(Logic::LessOrEqual(left, right)))
+        }),
+        infix(left(1), operator("&&"), |left, right| {
+            Expression::Logic(Box::new(Logic::And(left, right)))
+        }),
+        infix(left(1), operator("||"), |left, right| {
+            Expression::Logic(Box::new(Logic::Or(left, right)))
+        }),
+    ));
 
-        choice((logic, value))
+    logic_expression.then_ignore(end())
-    });
-
-    let statement = recursive(|statement| {
-        let assignment = text::ident()
-            .map(|text| Identifier::new(text))
-            .then(just("=").padded())
-            .then(statement)
-            .map(|((identifier, _), statement)| {
-                Statement::Assignment(Box::new(Assignment {
-                    identifier,
-                    statement,
-                }))
-            });
-
-        let expression = expression.map(|expression| Statement::Expression(expression));
-
-        choice((assignment, expression))
-    });
-
-    statement.then_ignore(end())
 }
 
 #[cfg(test)]
@@ -196,15 +173,15 @@ mod tests {
     fn parse_list() {
         assert_eq!(
             parser().parse("[]").unwrap(),
-            Statement::value(Value::List(vec![]))
+            Expression::Value(Value::List(vec![]))
         );
         assert_eq!(
             parser().parse("[42]").unwrap(),
-            Statement::value(Value::List(vec![Value::Integer(42)]))
+            Expression::Value(Value::List(vec![Value::Integer(42)]))
         );
         assert_eq!(
             parser().parse("[42, 'foo', \"bar\", [1, 2, 3,]]").unwrap(),
-            Statement::value(Value::List(vec![
+            Expression::Value(Value::List(vec![
                 Value::Integer(42),
                 Value::String("foo".to_string()),
                 Value::String("bar".to_string()),
@@ -221,7 +198,7 @@ mod tests {
     fn parse_true() {
         assert_eq!(
             parser().parse("true").unwrap(),
-            Statement::value(Value::Boolean(true))
+            Expression::Value(Value::Boolean(true))
         );
     }
 
@@ -229,7 +206,7 @@ mod tests {
     fn parse_false() {
         assert_eq!(
             parser().parse("false").unwrap(),
-            Statement::value(Value::Boolean(false))
+            Expression::Value(Value::Boolean(false))
         );
     }
 
@@ -237,25 +214,25 @@ mod tests {
     fn parse_positive_float() {
         assert_eq!(
             parser().parse("0.0").unwrap(),
-            Statement::value(Value::Float(0.0))
+            Expression::Value(Value::Float(0.0))
         );
         assert_eq!(
             parser().parse("42.0").unwrap(),
-            Statement::value(Value::Float(42.0))
+            Expression::Value(Value::Float(42.0))
         );
 
         let max_float = f64::MAX.to_string() + ".0";
 
         assert_eq!(
             parser().parse(&max_float).unwrap(),
-            Statement::value(Value::Float(f64::MAX))
+            Expression::Value(Value::Float(f64::MAX))
         );
 
         let min_positive_float = f64::MIN_POSITIVE.to_string();
 
         assert_eq!(
             parser().parse(&min_positive_float).unwrap(),
-            Statement::value(Value::Float(f64::MIN_POSITIVE))
+            Expression::Value(Value::Float(f64::MIN_POSITIVE))
         );
     }
 
@@ -263,25 +240,25 @@ mod tests {
     fn parse_negative_float() {
         assert_eq!(
             parser().parse("-0.0").unwrap(),
-            Statement::value(Value::Float(-0.0))
+            Expression::Value(Value::Float(-0.0))
         );
         assert_eq!(
             parser().parse("-42.0").unwrap(),
-            Statement::value(Value::Float(-42.0))
+            Expression::Value(Value::Float(-42.0))
         );
 
         let min_float = f64::MIN.to_string() + ".0";
 
         assert_eq!(
             parser().parse(&min_float).unwrap(),
-            Statement::value(Value::Float(f64::MIN))
+            Expression::Value(Value::Float(f64::MIN))
         );
 
-        let max_negative_float = f64::MIN_POSITIVE.to_string();
+        let max_negative_float = format!("-{}", f64::MIN_POSITIVE);
 
         assert_eq!(
             parser().parse(&max_negative_float).unwrap(),
-            Statement::value(Value::Float(-f64::MIN_POSITIVE))
+            Expression::Value(Value::Float(-f64::MIN_POSITIVE))
         );
     }
 
@@ -289,16 +266,14 @@ mod tests {
     fn parse_other_float() {
         assert_eq!(
             parser().parse("Infinity").unwrap(),
-            Statement::value(Value::Float(f64::INFINITY))
+            Expression::Value(Value::Float(f64::INFINITY))
         );
         assert_eq!(
             parser().parse("-Infinity").unwrap(),
-            Statement::value(Value::Float(f64::NEG_INFINITY))
+            Expression::Value(Value::Float(f64::NEG_INFINITY))
         );
 
-        if let Statement::Expression(Expression::Value(Value::Float(float))) =
+        if let Expression::Value(Value::Float(float)) = parser().parse("NaN").unwrap() {
-            parser().parse("NaN").unwrap()
-        {
             assert!(float.is_nan())
         } else {
             panic!("Expected a float.")
@@ -309,54 +284,54 @@ mod tests {
     fn parse_positive_integer() {
         assert_eq!(
             parser().parse("0").unwrap(),
-            Statement::value(Value::Integer(0))
+            Expression::Value(Value::Integer(0))
         );
         assert_eq!(
             parser().parse("1").unwrap(),
-            Statement::value(Value::Integer(1))
+            Expression::Value(Value::Integer(1))
         );
         assert_eq!(
             parser().parse("2").unwrap(),
-            Statement::value(Value::Integer(2))
+            Expression::Value(Value::Integer(2))
         );
         assert_eq!(
             parser().parse("3").unwrap(),
-            Statement::value(Value::Integer(3))
+            Expression::Value(Value::Integer(3))
         );
         assert_eq!(
             parser().parse("4").unwrap(),
-            Statement::value(Value::Integer(4))
+            Expression::Value(Value::Integer(4))
         );
         assert_eq!(
             parser().parse("5").unwrap(),
-            Statement::value(Value::Integer(5))
+            Expression::Value(Value::Integer(5))
         );
         assert_eq!(
             parser().parse("6").unwrap(),
-            Statement::value(Value::Integer(6))
+            Expression::Value(Value::Integer(6))
         );
         assert_eq!(
             parser().parse("7").unwrap(),
-            Statement::value(Value::Integer(7))
+            Expression::Value(Value::Integer(7))
         );
         assert_eq!(
             parser().parse("8").unwrap(),
-            Statement::value(Value::Integer(8))
+            Expression::Value(Value::Integer(8))
         );
         assert_eq!(
             parser().parse("9").unwrap(),
-            Statement::value(Value::Integer(9))
+            Expression::Value(Value::Integer(9))
         );
         assert_eq!(
             parser().parse("42").unwrap(),
-            Statement::value(Value::Integer(42))
+            Expression::Value(Value::Integer(42))
         );
 
         let maximum_integer = i64::MAX.to_string();
 
         assert_eq!(
             parser().parse(&maximum_integer).unwrap(),
-            Statement::value(Value::Integer(i64::MAX))
+            Expression::Value(Value::Integer(i64::MAX))
         );
     }
 
@@ -364,54 +339,54 @@ mod tests {
     fn parse_negative_integer() {
         assert_eq!(
             parser().parse("-0").unwrap(),
-            Statement::value(Value::Integer(-0))
+            Expression::Value(Value::Integer(-0))
         );
         assert_eq!(
             parser().parse("-1").unwrap(),
-            Statement::value(Value::Integer(-1))
+            Expression::Value(Value::Integer(-1))
         );
         assert_eq!(
             parser().parse("-2").unwrap(),
-            Statement::value(Value::Integer(-2))
+            Expression::Value(Value::Integer(-2))
         );
         assert_eq!(
             parser().parse("-3").unwrap(),
-            Statement::value(Value::Integer(-3))
+            Expression::Value(Value::Integer(-3))
         );
         assert_eq!(
             parser().parse("-4").unwrap(),
-            Statement::value(Value::Integer(-4))
+            Expression::Value(Value::Integer(-4))
         );
         assert_eq!(
             parser().parse("-5").unwrap(),
-            Statement::value(Value::Integer(-5))
+            Expression::Value(Value::Integer(-5))
         );
         assert_eq!(
             parser().parse("-6").unwrap(),
-            Statement::value(Value::Integer(-6))
+            Expression::Value(Value::Integer(-6))
         );
         assert_eq!(
             parser().parse("-7").unwrap(),
-            Statement::value(Value::Integer(-7))
+            Expression::Value(Value::Integer(-7))
         );
         assert_eq!(
             parser().parse("-8").unwrap(),
-            Statement::value(Value::Integer(-8))
+            Expression::Value(Value::Integer(-8))
         );
         assert_eq!(
             parser().parse("-9").unwrap(),
-            Statement::value(Value::Integer(-9))
+            Expression::Value(Value::Integer(-9))
         );
         assert_eq!(
             parser().parse("-42").unwrap(),
-            Statement::value(Value::Integer(-42))
+            Expression::Value(Value::Integer(-42))
         );
 
         let minimum_integer = i64::MIN.to_string();
 
         assert_eq!(
             parser().parse(&minimum_integer).unwrap(),
-            Statement::value(Value::Integer(i64::MIN))
+            Expression::Value(Value::Integer(i64::MIN))
         );
     }
 
@@ -419,19 +394,19 @@ mod tests {
     fn double_quoted_string() {
         assert_eq!(
             parser().parse("\"\"").unwrap(),
-            Statement::value(Value::String("".to_string()))
+            Expression::Value(Value::String("".to_string()))
         );
         assert_eq!(
             parser().parse("\"1\"").unwrap(),
-            Statement::value(Value::String("1".to_string()))
+            Expression::Value(Value::String("1".to_string()))
         );
         assert_eq!(
             parser().parse("\"42\"").unwrap(),
-            Statement::value(Value::String("42".to_string()))
+            Expression::Value(Value::String("42".to_string()))
         );
         assert_eq!(
             parser().parse("\"foobar\"").unwrap(),
-            Statement::value(Value::String("foobar".to_string()))
+            Expression::Value(Value::String("foobar".to_string()))
         );
     }
 
@@ -439,19 +414,19 @@ mod tests {
     fn single_quoted_string() {
         assert_eq!(
             parser().parse("''").unwrap(),
-            Statement::value(Value::String("".to_string()))
+            Expression::Value(Value::String("".to_string()))
         );
         assert_eq!(
             parser().parse("'1'").unwrap(),
-            Statement::value(Value::String("1".to_string()))
+            Expression::Value(Value::String("1".to_string()))
         );
         assert_eq!(
             parser().parse("'42'").unwrap(),
-            Statement::value(Value::String("42".to_string()))
+            Expression::Value(Value::String("42".to_string()))
         );
         assert_eq!(
             parser().parse("'foobar'").unwrap(),
-            Statement::value(Value::String("foobar".to_string()))
+            Expression::Value(Value::String("foobar".to_string()))
         );
     }
 
@@ -459,19 +434,19 @@ mod tests {
     fn grave_quoted_string() {
         assert_eq!(
             parser().parse("``").unwrap(),
-            Statement::value(Value::String("".to_string()))
+            Expression::Value(Value::String("".to_string()))
         );
         assert_eq!(
             parser().parse("`1`").unwrap(),
-            Statement::value(Value::String("1".to_string()))
+            Expression::Value(Value::String("1".to_string()))
         );
         assert_eq!(
             parser().parse("`42`").unwrap(),
-            Statement::value(Value::String("42".to_string()))
+            Expression::Value(Value::String("42".to_string()))
         );
         assert_eq!(
             parser().parse("`foobar`").unwrap(),
-            Statement::value(Value::String("foobar".to_string()))
+            Expression::Value(Value::String("foobar".to_string()))
         );
     }
 }