Begin using Positioned type

src/abstract_tree/assignment.rs

@@ -3,14 +3,14 @@ use crate::{
     Context,
 };
 
-use super::{AbstractTree, Action, Identifier, Statement, Type};
+use super::{AbstractTree, Action, Identifier, Positioned, Statement, Type};
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct Assignment {
     identifier: Identifier,
-    r#type: Option<Type>,
+    r#type: Option<Positioned<Type>>,
     operator: AssignmentOperator,
-    statement: Box<Statement>,
+    statement: Box<Positioned<Statement>>,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
@@ -23,9 +23,9 @@ pub enum AssignmentOperator {
 impl Assignment {
     pub fn new(
         identifier: Identifier,
-        r#type: Option<Type>,
+        r#type: Option<Positioned<Type>>,
         operator: AssignmentOperator,
-        statement: Statement,
+        statement: Positioned<Statement>,
     ) -> Self {
         Self {
             identifier,
@@ -42,24 +42,34 @@ impl AbstractTree for Assignment {
     }
 
     fn validate(&self, context: &Context) -> Result<(), ValidationError> {
-        let statement_type = self.statement.expected_type(context)?;
+        let statement_type = self.statement.node.expected_type(context)?;
 
-        if let Some(expected) = &self.r#type {
+        if let Some(Positioned {
-            expected.check(&statement_type)?;
+            node: expected_type,
+            position: expected_position,
+        }) = &self.r#type
+        {
+            expected_type.check(&statement_type).map_err(|conflict| {
+                ValidationError::TypeCheck {
+                    conflict,
+                    actual_position: self.statement.position,
+                    expected_position: expected_position.clone(),
+                }
+            })?;
 
-            context.set_type(self.identifier.clone(), expected.clone())?;
+            context.set_type(self.identifier.clone(), expected_type.clone())?;
         } else {
             context.set_type(self.identifier.clone(), statement_type)?;
         }
 
         self.identifier.validate(context)?;
-        self.statement.validate(context)?;
+        self.statement.node.validate(context)?;
 
         Ok(())
     }
 
     fn run(self, context: &Context) -> Result<Action, RuntimeError> {
-        let action = self.statement.run(context)?;
+        let action = self.statement.node.run(context)?;
         let value = match action {
             Action::Return(value) => value,
             r#break => return Ok(r#break),
@@ -101,7 +111,7 @@ impl AbstractTree for Assignment {
 mod tests {
     use crate::{
         abstract_tree::{Expression, ValueNode},
-        error::TypeCheckError,
+        error::TypeConflict,
         Value,
     };
 
@@ -115,7 +125,10 @@ mod tests {
             Identifier::new("foobar"),
             None,
             AssignmentOperator::Assign,
-            Statement::expression(Expression::Value(ValueNode::Integer(42)), (0..0).into()),
+            Positioned {
+                node: Statement::Expression(Expression::Value(ValueNode::Integer(42))),
+                position: (0, 0),
+            },
         )
         .run(&context)
         .unwrap();
@@ -138,7 +151,10 @@ mod tests {
             Identifier::new("foobar"),
             None,
             AssignmentOperator::AddAssign,
-            Statement::expression(Expression::Value(ValueNode::Integer(41)), (0..0).into()),
+            Positioned {
+                node: Statement::Expression(Expression::Value(ValueNode::Integer(41))),
+                position: (0, 0),
+            },
         )
         .run(&context)
         .unwrap();
@@ -161,7 +177,10 @@ mod tests {
             Identifier::new("foobar"),
             None,
             AssignmentOperator::SubAssign,
-            Statement::expression(Expression::Value(ValueNode::Integer(1)), (0..0).into()),
+            Positioned {
+                node: Statement::Expression(Expression::Value(ValueNode::Integer(1))),
+                position: (0, 0),
+            },
         )
         .run(&context)
         .unwrap();
@@ -176,18 +195,28 @@ mod tests {
     fn type_check() {
         let validation = Assignment::new(
             Identifier::new("foobar"),
-            Some(Type::Boolean),
+            Some(Positioned {
+                node: Type::Boolean,
+                position: (0, 0),
+            }),
             AssignmentOperator::Assign,
-            Statement::expression(Expression::Value(ValueNode::Integer(42)), (0..0).into()),
+            Positioned {
+                node: Statement::Expression(Expression::Value(ValueNode::Integer(42))),
+                position: (0, 0),
+            },
         )
         .validate(&Context::new());
 
         assert_eq!(
             validation,
-            Err(ValidationError::TypeCheck(TypeCheckError {
+            Err(ValidationError::TypeCheck {
-                actual: Type::Integer,
+                conflict: TypeConflict {
-                expected: Type::Boolean
+                    actual: Type::Integer,
-            }))
+                    expected: Type::Boolean
+                },
+                actual_position: (0, 0),
+                expected_position: (0, 0),
+            })
         )
     }
 }

src/abstract_tree/block.rs

@@ -61,9 +61,9 @@ mod tests {
     #[test]
     fn run_returns_value_of_final_statement() {
         let block = Block::new(vec![
-            Statement::expression(Expression::Value(ValueNode::Integer(1)), (0..0).into()),
+            Statement::Expression(Expression::Value(ValueNode::Integer(1))),
-            Statement::expression(Expression::Value(ValueNode::Integer(2)), (0..0).into()),
+            Statement::Expression(Expression::Value(ValueNode::Integer(2))),
-            Statement::expression(Expression::Value(ValueNode::Integer(42)), (0..0).into()),
+            Statement::Expression(Expression::Value(ValueNode::Integer(42))),
         ]);
 
         assert_eq!(
@@ -75,11 +75,8 @@ mod tests {
     #[test]
     fn expected_type_returns_type_of_final_statement() {
         let block = Block::new(vec![
-            Statement::expression(
+            Statement::Expression(Expression::Value(ValueNode::String("42".to_string()))),
-                Expression::Value(ValueNode::String("42".to_string())),
+            Statement::Expression(Expression::Value(ValueNode::Integer(42))),
-                (0..0).into(),
-            ),
-            Statement::expression(Expression::Value(ValueNode::Integer(42)), (0..0).into()),
         ]);
 
         assert_eq!(block.expected_type(&Context::new()), Ok(Type::Integer))

src/abstract_tree/if_else.rs

@@ -3,17 +3,21 @@ use crate::{
     error::{RuntimeError, ValidationError},
 };
 
-use super::{AbstractTree, Action, Block, Expression, Type};
+use super::{AbstractTree, Action, Block, Expression, Positioned, Type};
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct IfElse {
-    if_expression: Expression,
+    if_expression: Positioned<Expression>,
-    if_block: Block,
+    if_block: Positioned<Block>,
-    else_block: Option<Block>,
+    else_block: Option<Positioned<Block>>,
 }
 
 impl IfElse {
-    pub fn new(if_expression: Expression, if_block: Block, else_block: Option<Block>) -> Self {
+    pub fn new(
+        if_expression: Positioned<Expression>,
+        if_block: Positioned<Block>,
+        else_block: Option<Positioned<Block>>,
+    ) -> Self {
         Self {
             if_expression,
             if_block,
@@ -24,16 +28,22 @@ impl IfElse {
 
 impl AbstractTree for IfElse {
     fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
-        self.if_block.expected_type(_context)
+        self.if_block.node.expected_type(_context)
     }
 
     fn validate(&self, context: &Context) -> Result<(), ValidationError> {
-        if let Type::Boolean = self.if_expression.expected_type(context)? {
+        if let Type::Boolean = self.if_expression.node.expected_type(context)? {
             if let Some(else_block) = &self.else_block {
-                let expected = self.if_block.expected_type(context)?;
+                let expected = self.if_block.node.expected_type(context)?;
-                let actual = else_block.expected_type(context)?;
+                let actual = else_block.node.expected_type(context)?;
 
-                expected.check(&actual)?;
+                expected
+                    .check(&actual)
+                    .map_err(|conflict| ValidationError::TypeCheck {
+                        conflict,
+                        actual_position: self.if_block.position,
+                        expected_position: self.if_expression.position,
+                    })?;
             }
 
             Ok(())
@@ -45,14 +55,15 @@ impl AbstractTree for IfElse {
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
         let if_boolean = self
             .if_expression
+            .node
             .run(_context)?
             .as_return_value()?
             .as_boolean()?;
 
         if if_boolean {
-            self.if_block.run(_context)
+            self.if_block.node.run(_context)
         } else if let Some(else_statement) = self.else_block {
-            else_statement.run(_context)
+            else_statement.node.run(_context)
         } else {
             Ok(Action::None)
         }
@@ -72,11 +83,11 @@ mod tests {
     fn simple_if() {
         assert_eq!(
             IfElse::new(
-                Expression::Value(ValueNode::Boolean(true)),
+                Expression::Value(ValueNode::Boolean(true)).positioned((0, 0)),
-                Block::new(vec![Statement::expression(
+                Block::new(vec![Statement::Expression(Expression::Value(
-                    Expression::Value(ValueNode::String("foo".to_string())),
+                    ValueNode::String("foo".to_string())
-                    (0..0).into()
+                ),)])
-                )]),
+                .positioned((0, 0)),
                 None
             )
             .run(&Context::new()),
@@ -88,15 +99,17 @@ mod tests {
     fn simple_if_else() {
         assert_eq!(
             IfElse::new(
-                Expression::Value(ValueNode::Boolean(false)),
+                Expression::Value(ValueNode::Boolean(false)).positioned((0, 0)),
-                Block::new(vec![Statement::expression(
+                Block::new(vec![Statement::Expression(Expression::Value(
-                    Expression::Value(ValueNode::String("foo".to_string())),
+                    ValueNode::String("foo".to_string())
-                    (0..0).into()
+                ))])
-                ),]),
+                .positioned((0, 0)),
-                Some(Block::new(vec![Statement::expression(
+                Some(
-                    Expression::Value(ValueNode::String("bar".to_string())),
+                    Block::new(vec![Statement::Expression(Expression::Value(
-                    (0..0).into()
+                        ValueNode::String("bar".to_string())
-                )]))
+                    ))])
+                    .positioned((0, 0))
+                )
             )
             .run(&Context::new()),
             Ok(Action::Return(Value::string("bar".to_string())))

src/abstract_tree/item.rs

@@ -0,0 +1,39 @@
+use super::{AbstractTree, Expression, Positioned, Statement};
+
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+pub enum Item {
+    Expression(Positioned<Expression>),
+    Statement(Positioned<Statement>),
+}
+
+impl Item {
+    pub fn position(&self) -> &(usize, usize) {
+        match self {
+            Item::Expression((_, position)) => position,
+            Item::Statement((_, position)) => position,
+        }
+    }
+}
+
+impl AbstractTree for Item {
+    fn expected_type(
+        &self,
+        context: &crate::context::Context,
+    ) -> Result<super::Type, crate::error::ValidationError> {
+        todo!()
+    }
+
+    fn validate(
+        &self,
+        context: &crate::context::Context,
+    ) -> Result<(), crate::error::ValidationError> {
+        todo!()
+    }
+
+    fn run(
+        self,
+        context: &crate::context::Context,
+    ) -> Result<super::Action, crate::error::RuntimeError> {
+        todo!()
+    }
+}

src/abstract_tree/mod.rs

@@ -36,10 +36,23 @@ use crate::{
     Value,
 };
 
-pub trait AbstractTree {
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
+pub struct Positioned<T> {
+    pub node: T,
+    pub position: (usize, usize),
+}
+
+pub trait AbstractTree: Sized {
     fn expected_type(&self, context: &Context) -> Result<Type, ValidationError>;
     fn validate(&self, context: &Context) -> Result<(), ValidationError>;
     fn run(self, context: &Context) -> Result<Action, RuntimeError>;
+
+    fn positioned(self, position: (usize, usize)) -> Positioned<Self> {
+        Positioned {
+            node: self,
+            position,
+        }
+    }
 }
 
 #[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord)]

src/abstract_tree/statement.rs

@@ -8,72 +8,7 @@ use crate::{
 use super::{AbstractTree, Action, Assignment, Block, Expression, IfElse, Loop, Type, While};
 
 #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
-pub struct Statement {
+pub enum Statement {
-    pub inner: StatementInner,
-    pub span: (usize, usize),
-}
-
-impl Statement {
-    pub fn assignment(assignment: Assignment, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::Assignment(assignment),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn block(block: Block, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::Block(block),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn r#break(span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::Break,
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn expression(expression: Expression, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::Expression(expression),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn if_else(if_else: IfElse, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::IfElse(if_else),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn r#loop(r#loop: Loop, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::Loop(r#loop),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn r#while(r#while: While, span: SimpleSpan) -> Self {
-        Statement {
-            inner: StatementInner::While(r#while),
-            span: (span.start(), span.end()),
-        }
-    }
-
-    pub fn span(&self) -> (usize, usize) {
-        self.span
-    }
-
-    pub fn inner(&self) -> &StatementInner {
-        &self.inner
-    }
-}
-
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
-pub enum StatementInner {
     Assignment(Assignment),
     Block(Block),
     Break,
@@ -85,7 +20,7 @@ pub enum StatementInner {
 
 impl AbstractTree for Statement {
     fn expected_type(&self, _context: &Context) -> Result<Type, ValidationError> {
-        match &self.inner {
+        match self {
             StatementInner::Assignment(assignment) => assignment.expected_type(_context),
             StatementInner::Block(block) => block.expected_type(_context),
             StatementInner::Break => Ok(Type::None),
@@ -97,7 +32,7 @@ impl AbstractTree for Statement {
     }
 
     fn validate(&self, _context: &Context) -> Result<(), ValidationError> {
-        match &self.inner {
+        match self {
             StatementInner::Assignment(assignment) => assignment.validate(_context),
             StatementInner::Block(block) => block.validate(_context),
             StatementInner::Break => Ok(()),
@@ -109,7 +44,7 @@ impl AbstractTree for Statement {
     }
 
     fn run(self, _context: &Context) -> Result<Action, RuntimeError> {
-        match self.inner {
+        match self {
             StatementInner::Assignment(assignment) => assignment.run(_context),
             StatementInner::Block(block) => block.run(_context),
             StatementInner::Break => Ok(Action::Break),

src/abstract_tree/type.rs

@@ -3,7 +3,7 @@ use std::fmt::{self, Display, Formatter};
 use crate::{
     abstract_tree::Identifier,
     context::Context,
-    error::{RuntimeError, TypeCheckError, ValidationError},
+    error::{RuntimeError, TypeConflict, ValidationError},
 };
 
 use super::{AbstractTree, Action};
@@ -29,7 +29,7 @@ pub enum Type {
 }
 
 impl Type {
-    pub fn check(&self, other: &Type) -> Result<(), TypeCheckError> {
+    pub fn check(&self, other: &Type) -> Result<(), TypeConflict> {
         match (self, other) {
             (Type::Any, _)
             | (_, Type::Any)
@@ -49,7 +49,7 @@ impl Type {
                 if left == right {
                     Ok(())
                 } else {
-                    Err(TypeCheckError {
+                    Err(TypeConflict {
                         actual: other.clone(),
                         expected: self.clone(),
                     })
@@ -59,7 +59,7 @@ impl Type {
                 if let Ok(()) = left.check(right) {
                     Ok(())
                 } else {
-                    Err(TypeCheckError {
+                    Err(TypeConflict {
                         actual: left.as_ref().clone(),
                         expected: right.as_ref().clone(),
                     })
@@ -86,7 +86,7 @@ impl Type {
 
                 Ok(())
             }
-            _ => Err(TypeCheckError {
+            _ => Err(TypeConflict {
                 actual: other.clone(),
                 expected: self.clone(),
             }),
@@ -188,14 +188,14 @@ mod tests {
 
         assert_eq!(
             foo.check(&bar),
-            Err(TypeCheckError {
+            Err(TypeConflict {
                 actual: bar.clone(),
                 expected: foo.clone()
             })
         );
         assert_eq!(
             bar.check(&foo),
-            Err(TypeCheckError {
+            Err(TypeConflict {
                 actual: foo.clone(),
                 expected: bar.clone()
             })
@@ -222,7 +222,7 @@ mod tests {
 
             assert_eq!(
                 left.check(right),
-                Err(TypeCheckError {
+                Err(TypeConflict {
                     actual: right.clone(),
                     expected: left.clone()
                 })

src/error.rs

@@ -19,10 +19,7 @@ pub enum Error {
         span: (usize, usize),
     },
     Runtime(RuntimeError),
-    Validation {
+    Validation(ValidationError),
-        error: ValidationError,
-        span: (usize, usize),
-    },
 }
 
 impl Error {
@@ -49,33 +46,38 @@ impl Error {
                     .finish()
             }
             Error::Runtime(_) => todo!(),
-            Error::Validation { error, span } => {
+            Error::Validation(validation_error) => {
-                let mut report = Report::build(
+                let mut report =
-                    ReportKind::Custom("Validation Error", Color::White),
+                    Report::build(ReportKind::Custom("Validation Error", Color::White), (), 0);
-                    (),
-                    span.0,
-                );
 
-                match error {
+                match validation_error {
                     ValidationError::ExpectedBoolean => {
-                        report = report.with_label(
+                        report =
-                            Label::new(span.0..span.1).with_message("Expected boolean."),
+                            report.with_label(Label::new(0..0).with_message("Expected boolean."));
-                        );
                     }
                     ValidationError::ExpectedIntegerOrFloat => {
                         report = report.with_label(
-                            Label::new(span.0..span.1).with_message("Expected integer or float."),
+                            Label::new(0..0).with_message("Expected integer or float."),
                         );
                     }
                     ValidationError::RwLockPoison(_) => todo!(),
-                    ValidationError::TypeCheck(TypeCheckError { actual, expected }) => {
+                    ValidationError::TypeCheck {
-                        report = report.with_label(Label::new(span.0..span.1).with_message(
+                        conflict,
-                            format!("Type error. Expected {expected} but got {actual}."),
+                        actual_position,
-                        ));
+                        expected_position: expected_postion,
+                    } => {
+                        let TypeConflict { actual, expected } = conflict;
+
+                        report = report.with_labels([
+                            Label::new(expected_postion.0..expected_postion.1)
+                                .with_message(format!("Type {expected} established here.")),
+                            Label::new(actual_position.0..actual_position.1)
+                                .with_message(format!("Got type {actual} here.")),
+                        ]);
                     }
                     ValidationError::VariableNotFound(identifier) => {
                         report = report
-                            .with_label(Label::new(span.0..span.1).with_message(format!(
+                            .with_label(Label::new(0..0).with_message(format!(
                                 "The variable {identifier} does not exist."
                             )));
                     }
@@ -144,7 +146,16 @@ pub enum ValidationError {
     ExpectedValue,
     InterpreterExpectedReturn,
     RwLockPoison(RwLockPoisonError),
-    TypeCheck(TypeCheckError),
+    TypeCheck {
+        /// The mismatch that caused the error.
+        conflict: TypeConflict,
+
+        /// The position of the item that gave the "actual" type.
+        actual_position: (usize, usize),
+
+        /// The position of the item that gave the "expected" type.
+        expected_position: (usize, usize),
+    },
     VariableNotFound(Identifier),
 }
 
@@ -154,12 +165,6 @@ impl From<RwLockPoisonError> for ValidationError {
     }
 }
 
-impl From<TypeCheckError> for ValidationError {
-    fn from(error: TypeCheckError) -> Self {
-        ValidationError::TypeCheck(error)
-    }
-}
-
 #[derive(Debug, PartialEq)]
 pub struct RwLockPoisonError;
 
@@ -170,7 +175,7 @@ impl<T> From<PoisonError<T>> for RwLockPoisonError {
 }
 
 #[derive(Debug, PartialEq)]
-pub struct TypeCheckError {
+pub struct TypeConflict {
     pub actual: Type,
     pub expected: Type,
 }

src/lib.rs

@@ -36,11 +36,8 @@ impl Interpreter {
             .filter_map(|statement| {
                 statement
                     .validate(&self.context)
-                    .map_err(|validation_error| Error::Validation {
-                        error: validation_error,
-                        span: statement.span(),
-                    })
                     .err()
+                    .map(|validation_error| Error::Validation(validation_error))
             })
             .collect::<Vec<Error>>();
 

tests/values.rs

@@ -2,7 +2,7 @@ use std::collections::BTreeMap;
 
 use dust_lang::{
     abstract_tree::{Identifier, Type},
-    error::{Error, TypeCheckError, ValidationError},
+    error::{Error, TypeConflict, ValidationError},
     *,
 };
 
@@ -136,7 +136,7 @@ fn map_type_errors() {
     assert_eq!(
         interpret("{ foo : bool = 'bar' }"),
         Err(vec![Error::Validation {
-            error: ValidationError::TypeCheck(TypeCheckError {
+            error: ValidationError::TypeCheck(TypeConflict {
                 actual: Type::String,
                 expected: Type::Boolean
             }),

tests/variables.rs

@@ -1,6 +1,6 @@
 use dust_lang::{
     abstract_tree::{Block, Expression, Identifier, Statement, Type},
-    error::{Error, TypeCheckError, ValidationError},
+    error::{Error, TypeConflict, ValidationError},
     *,
 };
 
@@ -25,7 +25,7 @@ fn set_variable_with_type_error() {
     assert_eq!(
         interpret("foobar: str = true"),
         Err(vec![Error::Validation {
-            error: ValidationError::TypeCheck(TypeCheckError {
+            error: ValidationError::TypeCheck(TypeConflict {
                 actual: Type::Boolean,
                 expected: Type::String
             }),