Add plumbing

src/lib.rs

@@ -1,24 +1,168 @@
-use std::{collections::BTreeMap, ops::Range};
+use std::{
+    collections::BTreeMap,
+    ops::Range,
+    sync::{Arc, OnceLock, PoisonError, RwLock},
+};
 
 use chumsky::{prelude::*, Parser};
 
+pub static NONE: OnceLock<Value> = OnceLock::new();
+
+pub enum BuiltInValue {
+    None,
+}
+
+impl BuiltInValue {
+    pub fn get(&self) -> Value {
+        match self {
+            BuiltInValue::None => NONE.get_or_init(|| {
+                Value::r#enum(EnumInstance {
+                    type_name: Identifier("Option".to_string()),
+                    variant: Identifier("None".to_string()),
+                })
+            }),
+        }
+        .clone()
+    }
+}
+
+pub enum Error<'src> {
+    Parse(Vec<Rich<'src, char>>),
+    Runtime(RuntimeError),
+}
+
+impl<'src> From<Vec<Rich<'src, char>>> for Error<'src> {
+    fn from(errors: Vec<Rich<'src, char>>) -> Self {
+        Error::Parse(errors)
+    }
+}
+
+impl<'src> From<RuntimeError> for Error<'src> {
+    fn from(error: RuntimeError) -> Self {
+        Error::Runtime(error)
+    }
+}
+
+pub enum RuntimeError {
+    RwLockPoison(RwLockPoisonError),
+}
+
+impl From<RwLockPoisonError> for RuntimeError {
+    fn from(error: RwLockPoisonError) -> Self {
+        RuntimeError::RwLockPoison(error)
+    }
+}
+
+pub struct RwLockPoisonError;
+
+impl<T> From<PoisonError<T>> for RwLockPoisonError {
+    fn from(_: PoisonError<T>) -> Self {
+        RwLockPoisonError
+    }
+}
+
+pub struct Context {
+    inner: Arc<RwLock<BTreeMap<Identifier, Value>>>,
+}
+
+impl Context {
+    pub fn get(&self, identifier: &Identifier) -> Result<Option<Value>, RwLockPoisonError> {
+        let value = self.inner.read()?.get(&identifier).cloned();
+
+        Ok(value)
+    }
+
+    pub fn set(&self, identifier: Identifier, value: Value) -> Result<(), RwLockPoisonError> {
+        self.inner.write()?.insert(identifier, value);
+
+        Ok(())
+    }
+}
+
+pub trait AbstractTree {
+    fn run(self, context: &Context) -> Result<Value, RuntimeError>;
+}
+
+pub struct Interpreter<P> {
+    parser: P,
+    context: Context,
+}
+
+impl<'src, P> Interpreter<P>
+where
+    P: Parser<'src, &'src str, Statement, extra::Err<Rich<'src, char>>>,
+{
+    pub fn run(&self, source: &'src str) -> Result<Value, Error<'src>> {
+        let final_value = self
+            .parser
+            .parse(source)
+            .into_result()?
+            .run(&self.context)?;
+
+        Ok(final_value)
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum Statement {
     Assignment(Assignment),
+    Expression(Expression),
+}
+
+impl AbstractTree for Statement {
+    fn run(self, context: &Context) -> Result<Value, RuntimeError> {
+        match self {
+            Statement::Assignment(assignment) => assignment.run(context),
+            Statement::Expression(expression) => expression.run(context),
+        }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Expression {
     Identifier(Identifier),
     Logic(Logic),
     Value(Value),
 }
 
-#[derive(Clone, Debug, PartialEq)]
+impl AbstractTree for Expression {
+    fn run(self, context: &Context) -> Result<Value, RuntimeError> {
+        match self {
+            Expression::Identifier(identifier) => identifier.run(context),
+            Expression::Logic(logic) => logic.run(context),
+            Expression::Value(value) => value.run(context),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Identifier(String);
 
+impl AbstractTree for Identifier {
+    fn run(self, context: &Context) -> Result<Value, RuntimeError> {
+        let value = context
+            .get(&self)?
+            .unwrap_or_else(|| BuiltInValue::None.get())
+            .clone();
+
+        Ok(value)
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub struct Assignment {
     identifier: Identifier,
     value: Value,
 }
 
+impl AbstractTree for Assignment {
+    fn run(self, context: &Context) -> Result<Value, RuntimeError> {
+        context.set(self.identifier, self.value)?;
+
+        Ok(BuiltInValue::None.get().clone())
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub struct Logic {
     left: LogicExpression,
@@ -26,9 +170,22 @@ pub struct Logic {
     right: LogicExpression,
 }
 
+impl AbstractTree for Logic {
+    fn run(self, _: &Context) -> Result<Value, RuntimeError> {
+        todo!()
+    }
+}
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum LogicOperator {
     Equal,
+    NotEqual,
+    Greater,
+    Less,
+    GreaterOrEqual,
+    LessOrEqual,
+    And,
+    Or,
 }
 
 #[derive(Clone, Debug, PartialEq)]
@@ -39,14 +196,64 @@ pub enum LogicExpression {
 }
 
 #[derive(Clone, Debug, PartialEq)]
-pub enum Value {
+pub struct Value(Arc<ValueInner>);
+
+impl Value {
+    pub fn boolean(boolean: bool) -> Self {
+        Value(Arc::new(ValueInner::Boolean(boolean)))
+    }
+
+    pub fn float(float: f64) -> Self {
+        Value(Arc::new(ValueInner::Float(float)))
+    }
+
+    pub fn integer(integer: i64) -> Self {
+        Value(Arc::new(ValueInner::Integer(integer)))
+    }
+
+    pub fn list(list: Vec<Value>) -> Self {
+        Value(Arc::new(ValueInner::List(list)))
+    }
+
+    pub fn map(map: BTreeMap<Identifier, Value>) -> Self {
+        Value(Arc::new(ValueInner::Map(map)))
+    }
+
+    pub fn range(range: Range<i64>) -> Self {
+        Value(Arc::new(ValueInner::Range(range)))
+    }
+
+    pub fn string(string: String) -> Self {
+        Value(Arc::new(ValueInner::String(string)))
+    }
+
+    pub fn r#enum(r#enum: EnumInstance) -> Self {
+        Value(Arc::new(ValueInner::Enum(r#enum)))
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum ValueInner {
     Boolean(bool),
     Float(f64),
     Integer(i64),
     List(Vec<Value>),
-    Map(BTreeMap<String, Value>),
+    Map(BTreeMap<Identifier, Value>),
     Range(Range<i64>),
     String(String),
+    Enum(EnumInstance),
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct EnumInstance {
+    type_name: Identifier,
+    variant: Identifier,
+}
+
+impl AbstractTree for Value {
+    fn run(self, _: &Context) -> Result<Value, RuntimeError> {
+        Ok(self)
+    }
 }
 
 pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich<'src, char>>> {
@@ -55,17 +262,17 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
     let value = recursive(|value| {
         let boolean = just("true")
             .or(just("false"))
-            .map(|s: &str| Value::Boolean(s.parse().unwrap()));
+            .map(|s: &str| Value::boolean(s.parse().unwrap()));
 
         let float_numeric = just('-')
             .or_not()
             .then(text::int(10))
             .then(just('.').then(text::digits(10)))
             .to_slice()
-            .map(|text: &str| Value::Float(text.parse().unwrap()));
+            .map(|text: &str| Value::float(text.parse().unwrap()));
 
         let float_other = choice((just("Infinity"), just("-Infinity"), just("NaN")))
-            .map(|text| Value::Float(text.parse().unwrap()));
+            .map(|text| Value::float(text.parse().unwrap()));
 
         let float = choice((float_numeric, float_other));
 
@@ -76,7 +283,7 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
             .map(|text: &str| {
                 let integer = text.parse::<i64>().unwrap();
 
-                Value::Integer(integer)
+                Value::integer(integer)
             });
 
         let delimited_string = |delimiter| {
@@ -84,7 +291,7 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
                 .ignore_then(none_of(delimiter).repeated())
                 .then_ignore(just(delimiter))
                 .to_slice()
-                .map(|text: &str| Value::String(text[1..text.len() - 1].to_string()))
+                .map(|text: &str| Value::string(text[1..text.len() - 1].to_string()))
         };
 
         let string = choice((
@@ -100,7 +307,7 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
             .collect()
             .padded()
             .delimited_by(just('['), just(']'))
-            .map(|values| Value::List(values));
+            .map(|values| Value::list(values));
 
         choice((boolean, float, integer, string, list))
     });
@@ -120,7 +327,16 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
                 .clone()
                 .map(|logic| LogicExpression::Logic(Box::new(logic))),
         ))
-        .then(operator("==").map(|_| LogicOperator::Equal))
+        .then(choice((
+            operator("==").map(|_| LogicOperator::Equal),
+            operator("!=").map(|_| LogicOperator::NotEqual),
+            operator(">").map(|_| LogicOperator::Greater),
+            operator("<").map(|_| LogicOperator::Less),
+            operator(">=").map(|_| LogicOperator::GreaterOrEqual),
+            operator("<=").map(|_| LogicOperator::LessOrEqual),
+            operator("&&").map(|_| LogicOperator::And),
+            operator("||").map(|_| LogicOperator::Or),
+        )))
         .then(choice((
             value.clone().map(|value| LogicExpression::Value(value)),
             identifier.map(|identifier| LogicExpression::Identifier(identifier)),
@@ -133,12 +349,18 @@ pub fn parser<'src>() -> impl Parser<'src, &'src str, Statement, extra::Err<Rich
         })
     });
 
-    choice((
-        logic.map(|logic| Statement::Logic(logic)),
+    let expression = choice((
+        logic.map(|logic| Expression::Logic(logic)),
+        value.map(|value| Expression::Value(value)),
+        identifier.map(|identifier| Expression::Identifier(identifier)),
+    ));
+
+    let statement = choice((
         assignment.map(|assignment| Statement::Assignment(assignment)),
-        value.map(|value| Statement::Value(value)),
-        identifier.map(|identifier| Statement::Identifier(identifier)),
-    ))
+        expression.map(|expression| Statement::Expression(expression)),
+    ));
+
+    statement
 }
 
 #[cfg(test)]
@@ -149,25 +371,25 @@ mod tests {
     fn parse_identifier() {
         assert_eq!(
             parser().parse("x").unwrap(),
-            Statement::Identifier(Identifier("x".to_string()))
+            Statement::Expression(Expression::Identifier(Identifier("x".to_string())))
         );
         assert_eq!(
             parser().parse("foobar").unwrap(),
-            Statement::Identifier(Identifier("foobar".to_string())),
+            Statement::Expression(Expression::Identifier(Identifier("foobar".to_string())))
         );
         assert_eq!(
             parser().parse("HELLO").unwrap(),
-            Statement::Identifier(Identifier("HELLO".to_string())),
+            Statement::Expression(Expression::Identifier(Identifier("HELLO".to_string())))
         );
     }
 
     #[test]
     fn parse_assignment() {
         assert_eq!(
-            parser().parse("foobar=1").unwrap(),
+            parser().parse("foobar = 1").unwrap(),
             Statement::Assignment(Assignment {
                 identifier: Identifier("foobar".to_string()),
-                value: Value::Integer(1)
+                value: Value::integer(1)
             })
         );
     }
@@ -176,11 +398,11 @@ mod tests {
     fn parse_logic() {
         assert_eq!(
             parser().parse("x == 1").unwrap(),
-            Statement::Logic(Logic {
+            Statement::Expression(Expression::Logic(Logic {
                 left: LogicExpression::Identifier(Identifier("x".to_string())),
                 operator: LogicOperator::Equal,
-                right: LogicExpression::Value(Value::Integer(1))
-            })
+                right: LogicExpression::Value(Value::integer(1))
+            }))
         );
     }
 
@@ -188,24 +410,24 @@ mod tests {
     fn parse_list() {
         assert_eq!(
             parser().parse("[]").unwrap(),
-            Statement::Value(Value::List(vec![]))
+            Statement::Expression(Expression::Value(Value::list(vec![])))
         );
         assert_eq!(
             parser().parse("[42]").unwrap(),
-            Statement::Value(Value::List(vec![Value::Integer(42)]))
+            Statement::Expression(Expression::Value(Value::list(vec![Value::integer(42)])))
         );
         assert_eq!(
             parser().parse("[42, 'foo', \"bar\", [1, 2, 3,]]").unwrap(),
-            Statement::Value(Value::List(vec![
-                Value::Integer(42),
-                Value::String("foo".to_string()),
-                Value::String("bar".to_string()),
-                Value::List(vec![
-                    Value::Integer(1),
-                    Value::Integer(2),
-                    Value::Integer(3),
+            Statement::Expression(Expression::Value(Value::list(vec![
+                Value::integer(42),
+                Value::string("foo".to_string()),
+                Value::string("bar".to_string()),
+                Value::list(vec![
+                    Value::integer(1),
+                    Value::integer(2),
+                    Value::integer(3),
                 ])
-            ]))
+            ])))
         );
     }
 
@@ -213,7 +435,7 @@ mod tests {
     fn parse_true() {
         assert_eq!(
             parser().parse("true").unwrap(),
-            Statement::Value(Value::Boolean(true))
+            Statement::Expression(Expression::Value(Value::boolean(true)))
         );
     }
 
@@ -221,7 +443,7 @@ mod tests {
     fn parse_false() {
         assert_eq!(
             parser().parse("false").unwrap(),
-            Statement::Value(Value::Boolean(false))
+            Statement::Expression(Expression::Value(Value::boolean(false)))
         );
     }
 
@@ -229,25 +451,25 @@ mod tests {
     fn parse_positive_float() {
         assert_eq!(
             parser().parse("0.0").unwrap(),
-            Statement::Value(Value::Float(0.0))
+            Statement::Expression(Expression::Value(Value::float(0.0)))
         );
         assert_eq!(
             parser().parse("42.0").unwrap(),
-            Statement::Value(Value::Float(42.0))
+            Statement::Expression(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))
+            Statement::Expression(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))
+            Statement::Expression(Expression::Value(Value::float(f64::MIN_POSITIVE)))
         );
     }
 
@@ -255,25 +477,25 @@ mod tests {
     fn parse_negative_float() {
         assert_eq!(
             parser().parse("-0.0").unwrap(),
-            Statement::Value(Value::Float(-0.0))
+            Statement::Expression(Expression::Value(Value::float(-0.0)))
         );
         assert_eq!(
             parser().parse("-42.0").unwrap(),
-            Statement::Value(Value::Float(-42.0))
+            Statement::Expression(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))
+            Statement::Expression(Expression::Value(Value::float(f64::MIN)))
         );
 
         let max_negative_float = format!("-{}", f64::MIN_POSITIVE);
 
         assert_eq!(
             parser().parse(&max_negative_float).unwrap(),
-            Statement::Value(Value::Float(-f64::MIN_POSITIVE))
+            Statement::Expression(Expression::Value(Value::float(-f64::MIN_POSITIVE)))
         );
     }
 
@@ -281,127 +503,71 @@ mod tests {
     fn parse_other_float() {
         assert_eq!(
             parser().parse("Infinity").unwrap(),
-            Statement::Value(Value::Float(f64::INFINITY))
+            Statement::Expression(Expression::Value(Value::float(f64::INFINITY)))
         );
         assert_eq!(
             parser().parse("-Infinity").unwrap(),
-            Statement::Value(Value::Float(f64::NEG_INFINITY))
+            Statement::Expression(Expression::Value(Value::float(f64::NEG_INFINITY)))
         );
 
-        if let Statement::Value(Value::Float(float)) = parser().parse("NaN").unwrap() {
-            assert!(float.is_nan())
-        } else {
-            panic!("Expected a float.")
+        if let Statement::Expression(Expression::Value(Value(value_inner))) =
+            parser().parse("NaN").unwrap()
+        {
+            if let ValueInner::Float(float) = value_inner.as_ref() {
+                return assert!(float.is_nan());
             }
         }
 
+        panic!("Expected a float.")
+    }
+
     #[test]
     fn parse_positive_integer() {
+        for i in 0..10 {
+            let source = i.to_string();
+            let result = parser().parse(&source);
+
             assert_eq!(
-            parser().parse("0").unwrap(),
-            Statement::Value(Value::Integer(0))
-        );
-        assert_eq!(
-            parser().parse("1").unwrap(),
-            Statement::Value(Value::Integer(1))
-        );
-        assert_eq!(
-            parser().parse("2").unwrap(),
-            Statement::Value(Value::Integer(2))
-        );
-        assert_eq!(
-            parser().parse("3").unwrap(),
-            Statement::Value(Value::Integer(3))
-        );
-        assert_eq!(
-            parser().parse("4").unwrap(),
-            Statement::Value(Value::Integer(4))
-        );
-        assert_eq!(
-            parser().parse("5").unwrap(),
-            Statement::Value(Value::Integer(5))
-        );
-        assert_eq!(
-            parser().parse("6").unwrap(),
-            Statement::Value(Value::Integer(6))
-        );
-        assert_eq!(
-            parser().parse("7").unwrap(),
-            Statement::Value(Value::Integer(7))
-        );
-        assert_eq!(
-            parser().parse("8").unwrap(),
-            Statement::Value(Value::Integer(8))
-        );
-        assert_eq!(
-            parser().parse("9").unwrap(),
-            Statement::Value(Value::Integer(9))
-        );
+                result.unwrap(),
+                Statement::Expression(Expression::Value(Value::integer(i)))
+            )
+        }
+
         assert_eq!(
             parser().parse("42").unwrap(),
-            Statement::Value(Value::Integer(42))
+            Statement::Expression(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))
+            Statement::Expression(Expression::Value(Value::integer(i64::MAX)))
         );
     }
 
     #[test]
     fn parse_negative_integer() {
+        for i in -9..1 {
+            let source = i.to_string();
+            let result = parser().parse(&source);
+
             assert_eq!(
-            parser().parse("-0").unwrap(),
-            Statement::Value(Value::Integer(-0))
-        );
-        assert_eq!(
-            parser().parse("-1").unwrap(),
-            Statement::Value(Value::Integer(-1))
-        );
-        assert_eq!(
-            parser().parse("-2").unwrap(),
-            Statement::Value(Value::Integer(-2))
-        );
-        assert_eq!(
-            parser().parse("-3").unwrap(),
-            Statement::Value(Value::Integer(-3))
-        );
-        assert_eq!(
-            parser().parse("-4").unwrap(),
-            Statement::Value(Value::Integer(-4))
-        );
-        assert_eq!(
-            parser().parse("-5").unwrap(),
-            Statement::Value(Value::Integer(-5))
-        );
-        assert_eq!(
-            parser().parse("-6").unwrap(),
-            Statement::Value(Value::Integer(-6))
-        );
-        assert_eq!(
-            parser().parse("-7").unwrap(),
-            Statement::Value(Value::Integer(-7))
-        );
-        assert_eq!(
-            parser().parse("-8").unwrap(),
-            Statement::Value(Value::Integer(-8))
-        );
-        assert_eq!(
-            parser().parse("-9").unwrap(),
-            Statement::Value(Value::Integer(-9))
-        );
+                result.unwrap(),
+                Statement::Expression(Expression::Value(Value::integer(i)))
+            )
+        }
+
         assert_eq!(
             parser().parse("-42").unwrap(),
-            Statement::Value(Value::Integer(-42))
+            Statement::Expression(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))
+            Statement::Expression(Expression::Value(Value::integer(i64::MIN)))
         );
     }
 
@@ -409,19 +575,15 @@ mod tests {
     fn double_quoted_string() {
         assert_eq!(
             parser().parse("\"\"").unwrap(),
-            Statement::Value(Value::String("".to_string()))
-        );
-        assert_eq!(
-            parser().parse("\"1\"").unwrap(),
-            Statement::Value(Value::String("1".to_string()))
+            Statement::Expression(Expression::Value(Value::string("".to_string())))
         );
         assert_eq!(
             parser().parse("\"42\"").unwrap(),
-            Statement::Value(Value::String("42".to_string()))
+            Statement::Expression(Expression::Value(Value::string("42".to_string())))
         );
         assert_eq!(
             parser().parse("\"foobar\"").unwrap(),
-            Statement::Value(Value::String("foobar".to_string()))
+            Statement::Expression(Expression::Value(Value::string("foobar".to_string())))
         );
     }
 
@@ -429,19 +591,15 @@ mod tests {
     fn single_quoted_string() {
         assert_eq!(
             parser().parse("''").unwrap(),
-            Statement::Value(Value::String("".to_string()))
-        );
-        assert_eq!(
-            parser().parse("'1'").unwrap(),
-            Statement::Value(Value::String("1".to_string()))
+            Statement::Expression(Expression::Value(Value::string("".to_string())))
         );
         assert_eq!(
             parser().parse("'42'").unwrap(),
-            Statement::Value(Value::String("42".to_string()))
+            Statement::Expression(Expression::Value(Value::string("42".to_string())))
         );
         assert_eq!(
             parser().parse("'foobar'").unwrap(),
-            Statement::Value(Value::String("foobar".to_string()))
+            Statement::Expression(Expression::Value(Value::string("foobar".to_string())))
         );
     }
 
@@ -449,19 +607,15 @@ mod tests {
     fn grave_quoted_string() {
         assert_eq!(
             parser().parse("``").unwrap(),
-            Statement::Value(Value::String("".to_string()))
-        );
-        assert_eq!(
-            parser().parse("`1`").unwrap(),
-            Statement::Value(Value::String("1".to_string()))
+            Statement::Expression(Expression::Value(Value::string("".to_string())))
         );
         assert_eq!(
             parser().parse("`42`").unwrap(),
-            Statement::Value(Value::String("42".to_string()))
+            Statement::Expression(Expression::Value(Value::string("42".to_string())))
         );
         assert_eq!(
             parser().parse("`foobar`").unwrap(),
-            Statement::Value(Value::String("foobar".to_string()))
+            Statement::Expression(Expression::Value(Value::string("foobar".to_string())))
         );
     }
 }