Improve errors

src/abstract_tree/assignment.rs

@@ -1,6 +1,7 @@
 use crate::{
     error::{RuntimeError, ValidationError},
-    Context,
+    value::ValueInner,
+    Context, Value,
 };
 
 use super::{AbstractTree, Action, Identifier, Statement, Type, WithPosition};
@@ -70,40 +71,94 @@ impl AbstractTree for Assignment {
 
     fn run(self, context: &Context) -> Result<Action, RuntimeError> {
         let action = self.statement.node.run(context)?;
-        let value = match action {
+        let right = match action {
             Action::Return(value) => value,
             r#break => return Ok(r#break),
         };
 
         match self.operator {
             AssignmentOperator::Assign => {
-                context.set_value(self.identifier.node, value)?;
+                context.set_value(self.identifier.node, right)?;
             }
             AssignmentOperator::AddAssign => {
-                if let Some(previous_value) = context.get_value(&self.identifier.node)? {
+                if let Some(left) = context.get_value(&self.identifier.node)? {
-                    let new_value = previous_value.add(&value)?;
+                    let new_value = match (left.inner().as_ref(), right.inner().as_ref()) {
+                        (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                            let sum = left.saturating_add(*right);
 
+                            Value::integer(sum)
+                        }
+                        (ValueInner::Float(left), ValueInner::Float(right)) => {
+                            let sum = left + right;
+
+                            Value::float(sum)
+                        }
+                        (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                            let sum = left + *right as f64;
+
+                            Value::float(sum)
+                        }
+                        (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                            let sum = *left as f64 + right;
+
+                            Value::float(sum)
+                        }
+                        (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                            return Err(RuntimeError::ValidationFailure(
+                                ValidationError::ExpectedIntegerOrFloat(self.statement.position),
+                            ))
+                        }
+                        _ => {
+                            return Err(RuntimeError::ValidationFailure(
+                                ValidationError::ExpectedIntegerOrFloat(self.identifier.position),
+                            ))
+                        }
+                    };
                     context.set_value(self.identifier.node, new_value)?;
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::VariableNotFound {
+                        ValidationError::VariableNotFound(self.identifier.node),
-                            identifier: self.identifier.node,
-                            position: self.identifier.position,
-                        },
                     ));
                 }
             }
             AssignmentOperator::SubAssign => {
-                if let Some(previous_value) = context.get_value(&self.identifier.node)? {
+                if let Some(left) = context.get_value(&self.identifier.node)? {
-                    let new_value = previous_value.subtract(&value)?;
+                    let new_value = match (left.inner().as_ref(), right.inner().as_ref()) {
+                        (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                            let difference = left.saturating_sub(*right);
 
+                            Value::integer(difference)
+                        }
+                        (ValueInner::Float(left), ValueInner::Float(right)) => {
+                            let difference = left - right;
+
+                            Value::float(difference)
+                        }
+                        (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                            let difference = left - *right as f64;
+
+                            Value::float(difference)
+                        }
+                        (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                            let difference = *left as f64 - right;
+
+                            Value::float(difference)
+                        }
+                        (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                            return Err(RuntimeError::ValidationFailure(
+                                ValidationError::ExpectedIntegerOrFloat(self.statement.position),
+                            ))
+                        }
+                        _ => {
+                            return Err(RuntimeError::ValidationFailure(
+                                ValidationError::ExpectedIntegerOrFloat(self.identifier.position),
+                            ))
+                        }
+                    };
                     context.set_value(self.identifier.node, new_value)?;
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::VariableNotFound {
+                        ValidationError::VariableNotFound(self.identifier.node),
-                            identifier: self.identifier.node,
-                            position: self.identifier.position,
-                        },
                     ));
                 }
             }
@@ -118,7 +173,6 @@ mod tests {
     use crate::{
         abstract_tree::{Expression, ValueNode},
         error::TypeConflict,
-        Value,
     };
 
     use super::*;

src/abstract_tree/identifier.rs

@@ -28,10 +28,7 @@ impl AbstractTree for Identifier {
         if let Some(r#type) = context.get_type(self)? {
             Ok(r#type)
         } else {
-            Err(ValidationError::VariableNotFound {
+            Err(ValidationError::VariableNotFound(self.clone()))
-                identifier: todo!(),
-                position: todo!(),
-            })
         }
     }
 
@@ -39,10 +36,7 @@ impl AbstractTree for Identifier {
         if context.contains(self)? {
             Ok(())
         } else {
-            Err(ValidationError::VariableNotFound {
+            Err(ValidationError::VariableNotFound(self.clone()))
-                identifier: todo!(),
-                position: todo!(),
-            })
         }
     }
 
@@ -53,10 +47,7 @@ impl AbstractTree for Identifier {
             Ok(action)
         } else {
             Err(RuntimeError::ValidationFailure(
-                ValidationError::VariableNotFound {
+                ValidationError::VariableNotFound(self.clone()),
-                    identifier: todo!(),
-                    position: todo!(),
-                },
             ))
         }
     }

src/abstract_tree/if_else.rs

@@ -64,7 +64,14 @@ impl AbstractTree for IfElse {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let value = self.if_expression.node.run(_context)?.as_return_value()?;
+        let action = self.if_expression.node.run(_context)?;
+        let value = if let Action::Return(value) = action {
+            value
+        } else {
+            return Err(RuntimeError::ValidationFailure(
+                ValidationError::InterpreterExpectedReturn(self.if_expression.position),
+            ));
+        };
 
         if let ValueInner::Boolean(if_boolean) = value.inner().as_ref() {
             if *if_boolean {

src/abstract_tree/list_index.rs

@@ -69,8 +69,22 @@ impl AbstractTree for ListIndex {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let left_value = self.left.node.run(_context)?.as_return_value()?;
+        let left_action = self.left.node.run(_context)?;
-        let right_value = self.right.node.run(_context)?.as_return_value()?;
+        let left_value = if let Action::Return(value) = left_action {
+            value
+        } else {
+            return Err(RuntimeError::ValidationFailure(
+                ValidationError::InterpreterExpectedReturn(self.left.position),
+            ));
+        };
+        let right_action = self.right.node.run(_context)?;
+        let right_value = if let Action::Return(value) = right_action {
+            value
+        } else {
+            return Err(RuntimeError::ValidationFailure(
+                ValidationError::InterpreterExpectedReturn(self.left.position),
+            ));
+        };
 
         if let (Some(list), Some(index)) = (left_value.as_list(), right_value.as_integer()) {
             let found_item = list.get(index as usize);

src/abstract_tree/logic.rs

@@ -84,110 +84,100 @@ impl AbstractTree for Logic {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let boolean = match self {
+        let run_and_expect_value =
-            Logic::Equal(left, right) => {
+            |expression: WithPosition<Expression>| -> Result<Value, RuntimeError> {
-                let left = left.node.run(_context)?.as_return_value()?;
+                let action = expression.node.run(_context)?;
-                let right = right.node.run(_context)?.as_return_value()?;
+                let value = if let Action::Return(value) = action {
-
+                    value
-                left == right
-            }
-            Logic::NotEqual(left, right) => {
-                let left = left.node.run(_context)?.as_return_value()?;
-                let right = right.node.run(_context)?.as_return_value()?;
-
-                left != right
-            }
-            Logic::Greater(left, right) => {
-                let left = left.node.run(_context)?.as_return_value()?;
-                let right = right.node.run(_context)?.as_return_value()?;
-
-                left > right
-            }
-            Logic::Less(left, right) => {
-                let left = left.node.run(_context)?.as_return_value()?;
-                let right = right.node.run(_context)?.as_return_value()?;
-
-                left < right
-            }
-            Logic::GreaterOrEqual(left, right) => {
-                let left = left.node.run(_context)?.as_return_value()?;
-                let right = right.node.run(_context)?.as_return_value()?;
-
-                left >= right
-            }
-            Logic::LessOrEqual(left, right) => {
-                let left = left.node.run(_context)?.as_return_value()?;
-                let right = right.node.run(_context)?.as_return_value()?;
-
-                left <= right
-            }
-            Logic::And(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
-
-                let left = if let ValueInner::Boolean(boolean) = left_value.inner().as_ref() {
-                    boolean
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedBoolean {
+                        ValidationError::InterpreterExpectedReturn(expression.position),
-                            actual: left_value.r#type(),
-                            position: left.position,
-                        },
-                    ));
-                };
-                let right = if let ValueInner::Boolean(boolean) = right_value.inner().as_ref() {
-                    boolean
-                } else {
-                    return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedBoolean {
-                            actual: right_value.r#type(),
-                            position: right.position,
-                        },
                     ));
                 };
 
-                *left && *right
+                Ok(value)
-            }
+            };
-            Logic::Or(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
 
-                let left = if let ValueInner::Boolean(boolean) = left_value.inner().as_ref() {
+        let run_and_expect_boolean =
-                    boolean
+            |expression: WithPosition<Expression>| -> Result<bool, RuntimeError> {
+                let action = expression.node.run(_context)?;
+                let value = if let Action::Return(value) = action {
+                    value
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedBoolean {
+                        ValidationError::InterpreterExpectedReturn(expression.position),
-                            actual: left_value.r#type(),
-                            position: left.position,
-                        },
                     ));
                 };
-                let right = if let ValueInner::Boolean(boolean) = right_value.inner().as_ref() {
-                    boolean
-                } else {
-                    return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedBoolean {
-                            actual: right_value.r#type(),
-                            position: right.position,
-                        },
-                    ));
-                };
-
-                *left || *right
-            }
-            Logic::Not(statement) => {
-                let value = statement.node.run(_context)?.as_return_value()?;
 
                 if let ValueInner::Boolean(boolean) = value.inner().as_ref() {
-                    !boolean
+                    Ok(*boolean)
                 } else {
                     return Err(RuntimeError::ValidationFailure(
                         ValidationError::ExpectedBoolean {
                             actual: value.r#type(),
-                            position: statement.position,
+                            position: expression.position,
                         },
                     ));
                 }
+            };
+
+        let boolean = match self {
+            Logic::Equal(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value == right_value
+            }
+            Logic::NotEqual(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value != right_value
+            }
+            Logic::Greater(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value > right_value
+            }
+            Logic::Less(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value < right_value
+            }
+            Logic::GreaterOrEqual(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value >= right_value
+            }
+            Logic::LessOrEqual(left, right) => {
+                let (left_value, right_value) =
+                    (run_and_expect_value(left)?, run_and_expect_value(right)?);
+
+                left_value <= right_value
+            }
+            Logic::And(left, right) => {
+                let (left_boolean, right_boolean) = (
+                    run_and_expect_boolean(left)?,
+                    run_and_expect_boolean(right)?,
+                );
+
+                left_boolean && right_boolean
+            }
+            Logic::Or(left, right) => {
+                let (left_boolean, right_boolean) = (
+                    run_and_expect_boolean(left)?,
+                    run_and_expect_boolean(right)?,
+                );
+
+                left_boolean || right_boolean
+            }
+            Logic::Not(statement) => {
+                let boolean = run_and_expect_boolean(statement)?;
+
+                !boolean
             }
         };
 
@@ -203,148 +193,124 @@ mod tests {
 
     #[test]
     fn equal() {
-        assert!(Logic::Equal(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::Equal(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn not_equal() {
-        assert!(Logic::NotEqual(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::NotEqual(
-            Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn greater() {
-        assert!(Logic::Greater(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+            Logic::Greater(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn less() {
-        assert!(Logic::Less(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::Less(
-            Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn greater_or_equal() {
-        assert!(Logic::GreaterOrEqual(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::GreaterOrEqual(
-            Expression::Value(ValueNode::Integer(41)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        )
+                Expression::Value(ValueNode::Integer(41)).with_position((0, 0)),
-        .run(&Context::new())
+            )
-        .unwrap()
+            .run(&Context::new()),
-        .as_return_value()
+            Ok(Action::Return(Value::boolean(true)))
-        .unwrap()
+        );
-        .as_boolean()
-        .unwrap());
 
-        assert!(Logic::GreaterOrEqual(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::GreaterOrEqual(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        )
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        .run(&Context::new())
+            )
-        .unwrap()
+            .run(&Context::new()),
-        .as_return_value()
+            Ok(Action::Return(Value::boolean(true)))
-        .unwrap()
+        );
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn less_or_equal() {
-        assert!(Logic::LessOrEqual(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::LessOrEqual(
-            Expression::Value(ValueNode::Integer(43)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(41)).with_position((0, 0)),
-        )
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        .run(&Context::new())
+            )
-        .unwrap()
+            .run(&Context::new()),
-        .as_return_value()
+            Ok(Action::Return(Value::boolean(true)))
-        .unwrap()
+        );
-        .as_boolean()
-        .unwrap());
 
-        assert!(Logic::LessOrEqual(
+        assert_eq!(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+            Logic::LessOrEqual(
-            Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        )
+                Expression::Value(ValueNode::Integer(42)).with_position((0, 0)),
-        .run(&Context::new())
+            )
-        .unwrap()
+            .run(&Context::new()),
-        .as_return_value()
+            Ok(Action::Return(Value::boolean(true)))
-        .unwrap()
+        );
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn and() {
-        assert!(Logic::And(
+        assert_eq!(
-            Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+            Logic::And(
-            Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+                Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+                Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn or() {
-        assert!(Logic::Or(
+        assert_eq!(
-            Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+            Logic::Or(
-            Expression::Value(ValueNode::Boolean(false)).with_position((0, 0)),
+                Expression::Value(ValueNode::Boolean(true)).with_position((0, 0)),
+                Expression::Value(ValueNode::Boolean(false)).with_position((0, 0)),
+            )
+            .run(&Context::new()),
+            Ok(Action::Return(Value::boolean(true)))
         )
-        .run(&Context::new())
-        .unwrap()
-        .as_return_value()
-        .unwrap()
-        .as_boolean()
-        .unwrap())
     }
 
     #[test]
     fn not() {
-        assert!(
+        assert_eq!(
-            Logic::Not(Expression::Value(ValueNode::Boolean(false)).with_position((0, 0)))
+            Logic::Not(Expression::Value(ValueNode::Boolean(false)).with_position((0, 0)),)
-                .run(&Context::new())
+                .run(&Context::new()),
-                .unwrap()
+            Ok(Action::Return(Value::boolean(true)))
-                .as_return_value()
-                .unwrap()
-                .as_boolean()
-                .unwrap()
         )
     }
 }

src/abstract_tree/loop.rs

@@ -90,7 +90,7 @@ mod tests {
     fn complex_loop() {
         let action = Block::new(vec![
             Statement::Assignment(Assignment::new(
-                Identifier::new("i"),
+                Identifier::new("i").with_position((0, 0)),
                 None,
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::Integer(1)))
@@ -105,7 +105,7 @@ mod tests {
                 .with_position((10, 15)),
                 Block::new(vec![Statement::Break.with_position((18, 24))]),
                 Some(Block::new(vec![Statement::Assignment(Assignment::new(
-                    Identifier::new("i"),
+                    Identifier::new("i").with_position((0, 0)),
                     None,
                     AssignmentOperator::AddAssign,
                     Statement::Expression(Expression::Value(ValueNode::Integer(1)))

src/abstract_tree/map_index.rs

@@ -39,9 +39,10 @@ impl AbstractTree for MapIndex {
                 return if let Some(value) = map.get(index_identifier) {
                     Ok(value.r#type())
                 } else {
-                    Err(ValidationError::PropertyNotFound(
+                    Err(ValidationError::PropertyNotFound {
-                        collection_identifier.clone(),
+                        identifier: index_identifier.clone(),
-                    ))
+                        position: self.right.position,
+                    })
                 };
             };
         }
@@ -72,7 +73,7 @@ impl AbstractTree for MapIndex {
 
         Err(ValidationError::CannotIndexWith {
             collection_type: left_type,
-            collection_position: todo!(),
+            collection_position: self.left.position,
             index_type: self.right.node.expected_type(_context)?,
             index_position: self.right.position,
         })
@@ -100,7 +101,14 @@ impl AbstractTree for MapIndex {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let collection = self.left.node.run(_context)?.as_return_value()?;
+        let action = self.left.node.run(_context)?;
+        let collection = if let Action::Return(value) = action {
+            value
+        } else {
+            return Err(RuntimeError::ValidationFailure(
+                ValidationError::InterpreterExpectedReturn(self.left.position),
+            ));
+        };
 
         if let (ValueInner::Map(map), Expression::Identifier(identifier)) =
             (collection.inner().as_ref(), &self.right.node)
@@ -115,7 +123,7 @@ impl AbstractTree for MapIndex {
             Err(RuntimeError::ValidationFailure(
                 ValidationError::CannotIndexWith {
                     collection_type: collection.r#type(),
-                    collection_position: todo!(),
+                    collection_position: self.left.position,
                     index_type: self.right.node.expected_type(_context)?,
                     index_position: self.right.position,
                 },

src/abstract_tree/math.rs

@@ -5,7 +5,7 @@ use crate::{
     Value,
 };
 
-use super::{AbstractTree, Action, Expression, Type, WithPosition};
+use super::{AbstractTree, Action, Expression, SourcePosition, Type, WithPosition};
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub enum Math {
@@ -37,71 +37,218 @@ impl AbstractTree for Math {
                 let left_type = left.node.expected_type(context)?;
                 let right_type = right.node.expected_type(context)?;
 
-                match (left_type, right_type) {
+                if let Type::Integer | Type::Float = left_type {
-                    (Type::Integer, Type::Integer)
+                    if let Type::Integer | Type::Float = right_type {
-                    | (Type::Float, Type::Float)
+                        Ok(())
-                    | (Type::Integer, Type::Float)
+                    } else {
-                    | (Type::Float, Type::Integer) => Ok(()),
+                        Err(ValidationError::ExpectedIntegerOrFloat(right.position))
-                    _ => Err(ValidationError::ExpectedIntegerOrFloat),
+                    }
+                } else {
+                    Err(ValidationError::ExpectedIntegerOrFloat(left.position))
                 }
             }
         }
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        let value = match self {
+        let run_and_expect_value =
-            Math::Add(left, right) => {
+            |expression: Expression, position: SourcePosition| -> Result<Value, RuntimeError> {
-                let left_value = left.node.run(_context)?.as_return_value()?;
+                let action = expression.run(_context)?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
+                let value = if let Action::Return(value) = action {
-
+                    value
-                left_value.add(&right_value)?
-            }
-            Math::Subtract(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
-
-                left_value.subtract(&right_value)?
-            }
-            Math::Multiply(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
-
-                if let (ValueInner::Integer(left), ValueInner::Integer(right)) =
-                    (left_value.inner().as_ref(), right_value.inner().as_ref())
-                {
-                    Value::integer(left * right)
                 } else {
                     return Err(RuntimeError::ValidationFailure(
-                        ValidationError::ExpectedIntegerOrFloat,
+                        ValidationError::InterpreterExpectedReturn(position),
                     ));
+                };
+
+                Ok(value)
+            };
+
+        let value = match self {
+            Math::Add(left, right) => {
+                let left_value = run_and_expect_value(left.node, left.position)?;
+                let right_value = run_and_expect_value(right.node, right.position)?;
+
+                match (left_value.inner().as_ref(), right_value.inner().as_ref()) {
+                    (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                        let sum = left.saturating_add(*right);
+
+                        Value::integer(sum)
+                    }
+                    (ValueInner::Float(left), ValueInner::Float(right)) => {
+                        let sum = left + right;
+
+                        Value::float(sum)
+                    }
+                    (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                        let sum = left + *right as f64;
+
+                        Value::float(sum)
+                    }
+                    (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                        let sum = *left as f64 + right;
+
+                        Value::float(sum)
+                    }
+                    (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(right.position),
+                        ))
+                    }
+                    _ => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(left.position),
+                        ))
+                    }
+                }
+            }
+            Math::Subtract(left, right) => {
+                let left_value = run_and_expect_value(left.node, left.position)?;
+                let right_value = run_and_expect_value(right.node, right.position)?;
+
+                match (left_value.inner().as_ref(), right_value.inner().as_ref()) {
+                    (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                        let difference = left.saturating_sub(*right);
+
+                        Value::integer(difference)
+                    }
+                    (ValueInner::Float(left), ValueInner::Float(right)) => {
+                        let difference = left - right;
+
+                        Value::float(difference)
+                    }
+                    (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                        let difference = left - *right as f64;
+
+                        Value::float(difference)
+                    }
+                    (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                        let difference = *left as f64 - right;
+
+                        Value::float(difference)
+                    }
+                    (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(right.position),
+                        ))
+                    }
+                    _ => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(left.position),
+                        ))
+                    }
+                }
+            }
+            Math::Multiply(left, right) => {
+                let left_value = run_and_expect_value(left.node, left.position)?;
+                let right_value = run_and_expect_value(right.node, right.position)?;
+
+                match (left_value.inner().as_ref(), right_value.inner().as_ref()) {
+                    (ValueInner::Integer(left), ValueInner::Integer(right)) => {
+                        let product = left.saturating_mul(*right);
+
+                        Value::integer(product)
+                    }
+                    (ValueInner::Float(left), ValueInner::Float(right)) => {
+                        let product = left * right;
+
+                        Value::float(product)
+                    }
+                    (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                        let product = left * *right as f64;
+
+                        Value::float(product)
+                    }
+                    (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                        let product = *left as f64 * right;
+
+                        Value::float(product)
+                    }
+                    (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(right.position).into(),
+                        ))
+                    }
+                    _ => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(left.position),
+                        ))
+                    }
                 }
             }
             Math::Divide(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
+                let left_value = run_and_expect_value(left.node, left.position)?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
+                let right_value = run_and_expect_value(right.node, right.position)?;
 
-                if let (ValueInner::Integer(left), ValueInner::Integer(right)) =
+                match (left_value.inner().as_ref(), right_value.inner().as_ref()) {
-                    (left_value.inner().as_ref(), right_value.inner().as_ref())
+                    (ValueInner::Integer(left), ValueInner::Integer(right)) => {
-                {
+                        let quotient = left.saturating_div(*right);
-                    Value::integer(left / right)
+
-                } else {
+                        Value::integer(quotient)
-                    return Err(RuntimeError::ValidationFailure(
+                    }
-                        ValidationError::ExpectedIntegerOrFloat,
+                    (ValueInner::Float(left), ValueInner::Float(right)) => {
-                    ));
+                        let quotient = left / right;
+
+                        Value::float(quotient)
+                    }
+                    (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                        let quotient = left / *right as f64;
+
+                        Value::float(quotient)
+                    }
+                    (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                        let quotient = *left as f64 / right;
+
+                        Value::float(quotient)
+                    }
+                    (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(right.position).into(),
+                        ))
+                    }
+                    _ => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(left.position),
+                        ))
+                    }
                 }
             }
             Math::Modulo(left, right) => {
-                let left_value = left.node.run(_context)?.as_return_value()?;
+                let left_value = run_and_expect_value(left.node, left.position)?;
-                let right_value = right.node.run(_context)?.as_return_value()?;
+                let right_value = run_and_expect_value(right.node, right.position)?;
 
-                if let (ValueInner::Integer(left), ValueInner::Integer(right)) =
+                match (left_value.inner().as_ref(), right_value.inner().as_ref()) {
-                    (left_value.inner().as_ref(), right_value.inner().as_ref())
+                    (ValueInner::Integer(left), ValueInner::Integer(right)) => {
-                {
+                        let remainder = left % right;
-                    Value::integer(left % right)
+
-                } else {
+                        Value::integer(remainder)
-                    return Err(RuntimeError::ValidationFailure(
+                    }
-                        ValidationError::ExpectedIntegerOrFloat,
+                    (ValueInner::Float(left), ValueInner::Float(right)) => {
-                    ));
+                        let remainder = left % right;
+
+                        Value::float(remainder)
+                    }
+                    (ValueInner::Float(left), ValueInner::Integer(right)) => {
+                        let remainder = left % *right as f64;
+
+                        Value::float(remainder)
+                    }
+                    (ValueInner::Integer(left), ValueInner::Float(right)) => {
+                        let remainder = *left as f64 % right;
+
+                        Value::float(remainder)
+                    }
+                    (ValueInner::Integer(_) | ValueInner::Float(_), _) => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(right.position).into(),
+                        ))
+                    }
+                    _ => {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::ExpectedIntegerOrFloat(left.position),
+                        ))
+                    }
                 }
             }
         };

src/abstract_tree/value_node.rs

@@ -121,7 +121,14 @@ impl AbstractTree for ValueNode {
                 let mut value_list = Vec::with_capacity(expression_list.len());
 
                 for expression in expression_list {
-                    let value = expression.node.run(_context)?.as_return_value()?;
+                    let action = expression.node.run(_context)?;
+                    let value = if let Action::Return(value) = action {
+                        value
+                    } else {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::InterpreterExpectedReturn(expression.position),
+                        ));
+                    };
 
                     value_list.push(value);
                 }
@@ -132,7 +139,14 @@ impl AbstractTree for ValueNode {
                 let mut property_map = BTreeMap::new();
 
                 for (identifier, _type, expression) in property_list {
-                    let value = expression.node.run(_context)?.as_return_value()?;
+                    let action = expression.node.run(_context)?;
+                    let value = if let Action::Return(value) = action {
+                        value
+                    } else {
+                        return Err(RuntimeError::ValidationFailure(
+                            ValidationError::InterpreterExpectedReturn(expression.position),
+                        ));
+                    };
 
                     property_map.insert(identifier, value);
                 }

src/abstract_tree/while.rs

@@ -42,9 +42,15 @@ impl AbstractTree for While {
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
         let get_boolean = || -> Result<Value, RuntimeError> {
-            let value = self.expression.node.run(_context)?.as_return_value()?;
+            let action = self.expression.node.run(_context)?;
 
-            Ok(value)
+            if let Action::Return(value) = action {
+                Ok(value)
+            } else {
+                Err(RuntimeError::ValidationFailure(
+                    ValidationError::InterpreterExpectedReturn(self.expression.position),
+                ))
+            }
         };
 
         if let ValueInner::Boolean(boolean) = get_boolean()?.inner().as_ref() {
@@ -77,7 +83,7 @@ mod tests {
     fn simple_while_loop() {
         let action = Statement::Block(Block::new(vec![
             Statement::Assignment(Assignment::new(
-                Identifier::new("i"),
+                Identifier::new("i").with_position((0, 0)),
                 None,
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::Integer(3)))
@@ -91,7 +97,7 @@ mod tests {
                 )))
                 .with_position((0, 0)),
                 statements: vec![Statement::Assignment(Assignment::new(
-                    Identifier::new("i"),
+                    Identifier::new("i").with_position((0, 0)),
                     None,
                     AssignmentOperator::AddAssign,
                     Statement::Expression(Expression::Value(ValueNode::Integer(1)))

src/error.rs

@@ -96,6 +96,7 @@ impl Error {
         };
 
         let type_color = Color::Green;
+        let identifier_color = Color::Blue;
 
         if let Some(validation_error) = validation_error {
             match validation_error {
@@ -133,16 +134,10 @@ impl Error {
                             .with_message(format!("Got type {} here.", actual.fg(type_color))),
                     ]);
                 }
-                ValidationError::VariableNotFound {
+                ValidationError::VariableNotFound(identifier) => builder.set_message(format!(
-                    identifier,
+                    "{} does not exist in this context.",
-                    position,
+                    identifier.fg(identifier_color)
-                } => {
+                )),
-                    builder.add_label(
-                        Label::new(("input", position.0..position.1))
-                            .with_message(format!("The variable {identifier} does not exist."))
-                            .with_priority(1),
-                    );
-                }
                 ValidationError::CannotIndex { r#type, position } => builder.add_label(
                     Label::new(("input", position.0..position.1))
                         .with_message(format!("Cannot index into a {}.", r#type.fg(type_color))),
@@ -270,11 +265,7 @@ pub enum ValidationError {
         /// The position of the item that gave the "expected" type.
         expected_position: SourcePosition,
     },
-    VariableNotFound {
+    VariableNotFound(Identifier),
-        identifier: Identifier,
-        position: SourcePosition,
-    },
-
     PropertyNotFound {
         identifier: Identifier,
         position: SourcePosition,

src/main.rs

@@ -1,13 +1,12 @@
 //! Command line interface for the dust programming language.
 
-use ariadne::{sources, Color, Label, Report, ReportKind, Source};
+use ariadne::sources;
-use chumsky::span::SimpleSpan;
 use clap::Parser;
 use colored::Colorize;
 
-use std::{fs::read_to_string, io::Write, ops::Range};
+use std::{fs::read_to_string, io::Write};
 
-use dust_lang::{context::Context, error::Error, Interpreter};
+use dust_lang::{context::Context, Interpreter};
 
 /// Command-line arguments to be parsed.
 #[derive(Parser, Debug)]
@@ -55,58 +54,8 @@ fn main() {
         }
         Err(errors) => {
             for error in errors {
-                let mut report_builder = match &error {
+                error
-                    Error::Parse { expected, span } => {
+                    .build_report()
-                        let message = if expected.is_empty() {
-                            "Invalid token.".to_string()
-                        } else {
-                            format!("Expected {expected}.")
-                        };
-
-                        Report::build(
-                            ReportKind::Custom("Parsing Error", Color::White),
-                            "input",
-                            span.1,
-                        )
-                        .with_label(
-                            Label::new(("input", span.0..span.1))
-                                .with_message(message)
-                                .with_color(Color::Red),
-                        )
-                    }
-                    Error::Lex { expected, span } => {
-                        let message = if expected.is_empty() {
-                            "Invalid token.".to_string()
-                        } else {
-                            format!("Expected {expected}.")
-                        };
-
-                        Report::build(
-                            ReportKind::Custom("Dust Error", Color::White),
-                            "input",
-                            span.1,
-                        )
-                        .with_label(
-                            Label::new(("input", span.0..span.1))
-                                .with_message(message)
-                                .with_color(Color::Red),
-                        )
-                    }
-                    Error::Runtime { error, position } => Report::build(
-                        ReportKind::Custom("Dust Error", Color::White),
-                        "input",
-                        position.1,
-                    ),
-                    Error::Validation { error, position } => Report::build(
-                        ReportKind::Custom("Dust Error", Color::White),
-                        "input",
-                        position.1,
-                    ),
-                };
-
-                report_builder = error.build_report(report_builder);
-
-                report_builder
                     .finish()
                     .eprint(sources([("input", &source)]))
                     .unwrap()

src/parser.rs

@@ -491,7 +491,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar : bool = true").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(Type::Boolean.with_position((9, 14))),
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::Boolean(true)))
@@ -505,7 +505,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar: list = []").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(Type::List.with_position((8, 13))),
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::List(vec![])))
@@ -519,7 +519,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar : list(bool) = [true]").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(Type::ListOf(Box::new(Type::Boolean)).with_position((9, 20))),
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::List(vec![Expression::Value(
@@ -536,7 +536,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar : [bool, str] = [true, '42']").unwrap()).unwrap()[0],
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(Type::ListExact(vec![Type::Boolean, Type::String]).with_position((9, 21))),
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::List(vec![
@@ -554,7 +554,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar : () -> any = some_function").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(
                     Type::Function {
                         parameter_types: vec![],
@@ -709,7 +709,7 @@ mod tests {
                 .with_position((10, 15)),
                 Block::new(vec![Statement::Break.with_position((18, 24))]),
                 Some(Block::new(vec![Statement::Assignment(Assignment::new(
-                    Identifier::new("i"),
+                    Identifier::new("i").with_position((33, 34)),
                     None,
                     AssignmentOperator::AddAssign,
                     Statement::Expression(Expression::Value(ValueNode::Integer(1)))
@@ -799,7 +799,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar = 1").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 None,
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::Integer(1)))
@@ -813,7 +813,7 @@ mod tests {
         assert_eq!(
             parse(&lex("foobar: int = 1").unwrap()).unwrap()[0].node,
             Statement::Assignment(Assignment::new(
-                Identifier::new("foobar"),
+                Identifier::new("foobar").with_position((0, 6)),
                 Some(Type::Integer.with_position((8, 12))),
                 AssignmentOperator::Assign,
                 Statement::Expression(Expression::Value(ValueNode::Integer(1)))

src/value.rs

@@ -16,7 +16,7 @@ use stanza::{
 use crate::{
     abstract_tree::{AbstractTree, Action, Block, Identifier, Type, WithPosition},
     context::Context,
-    error::{RuntimeError, ValidationError},
+    error::RuntimeError,
 };
 
 #[derive(Clone, Debug, PartialEq)]
@@ -127,58 +127,6 @@ impl Value {
             None
         }
     }
-
-    pub fn add(&self, other: &Self) -> Result<Value, ValidationError> {
-        match (self.inner().as_ref(), other.inner().as_ref()) {
-            (ValueInner::Integer(left), ValueInner::Integer(right)) => {
-                let sum = left.saturating_add(*right);
-
-                Ok(Value::integer(sum))
-            }
-            (ValueInner::Float(left), ValueInner::Float(right)) => {
-                let sum = left + right;
-
-                Ok(Value::float(sum))
-            }
-            (ValueInner::Float(left), ValueInner::Integer(right)) => {
-                let sum = left + *right as f64;
-
-                Ok(Value::float(sum))
-            }
-            (ValueInner::Integer(left), ValueInner::Float(right)) => {
-                let sum = *left as f64 + right;
-
-                Ok(Value::float(sum))
-            }
-            _ => Err(ValidationError::ExpectedIntegerOrFloat),
-        }
-    }
-
-    pub fn subtract(&self, other: &Self) -> Result<Value, ValidationError> {
-        match (self.inner().as_ref(), other.inner().as_ref()) {
-            (ValueInner::Integer(left), ValueInner::Integer(right)) => {
-                let sum = left.saturating_sub(*right);
-
-                Ok(Value::integer(sum))
-            }
-            (ValueInner::Float(left), ValueInner::Float(right)) => {
-                let sum = left - right;
-
-                Ok(Value::float(sum))
-            }
-            (ValueInner::Float(left), ValueInner::Integer(right)) => {
-                let sum = left - *right as f64;
-
-                Ok(Value::float(sum))
-            }
-            (ValueInner::Integer(left), ValueInner::Float(right)) => {
-                let sum = *left as f64 - right;
-
-                Ok(Value::float(sum))
-            }
-            _ => Err(ValidationError::ExpectedIntegerOrFloat),
-        }
-    }
 }
 
 impl Display for Value {