Add seperate interpreter step for type checking

src/abstract_tree/assignment.rs

@@ -26,7 +26,6 @@ impl AbstractTree for Assignment {
 
         let identifier_node = node.child(0).unwrap();
         let identifier = Identifier::from_syntax_node(source, identifier_node, context)?;
-        let identifier_type = identifier.expected_type(context)?;
 
         let type_node = node.child(1).unwrap();
         let type_definition = if type_node.kind() == "type_definition" {
@@ -54,43 +53,6 @@ impl AbstractTree for Assignment {
 
         let statement_node = node.child(child_count - 1).unwrap();
         let statement = Statement::from_syntax_node(source, statement_node, context)?;
-        let statement_type = statement.expected_type(context)?;
-
-        if let Some(type_definition) = &type_definition {
-            match operator {
-                AssignmentOperator::Equal => {
-                    type_definition
-                        .inner()
-                        .check(&statement_type)
-                        .map_err(|error| error.at_node(statement_node, source))?;
-                }
-                AssignmentOperator::PlusEqual => {
-                    if let Type::List(item_type) = type_definition.inner() {
-                        item_type
-                            .check(&statement_type)
-                            .map_err(|error| error.at_node(statement_node, source))?;
-                    } else {
-                        type_definition
-                            .inner()
-                            .check(&identifier_type)
-                            .map_err(|error| error.at_node(identifier_node, source))?;
-                    }
-                }
-                AssignmentOperator::MinusEqual => todo!(),
-            }
-        } else {
-            match operator {
-                AssignmentOperator::Equal => {}
-                AssignmentOperator::PlusEqual => {
-                    if let Type::List(item_type) = identifier_type {
-                        item_type
-                            .check(&statement_type)
-                            .map_err(|error| error.at_node(statement_node, source))?;
-                    }
-                }
-                AssignmentOperator::MinusEqual => todo!(),
-            }
-        }
 
         let variable_key = identifier.inner().clone();
         let variable_type = if let Some(definition) = &type_definition {
@@ -98,7 +60,7 @@ impl AbstractTree for Assignment {
         } else if let Some((_, r#type)) = context.variables()?.get(identifier.inner()) {
             r#type.clone()
         } else {
-            statement_type
+            statement.expected_type(context)?
         };
 
         context.set(variable_key, Value::none(), Some(variable_type))?;
@@ -111,6 +73,40 @@ impl AbstractTree for Assignment {
         })
     }
 
+    fn check_type(&self, _source: &str, context: &Map) -> Result<()> {
+        let statement_type = self.statement.expected_type(context)?;
+
+        if let Some(type_definition) = &self.type_definition {
+            match self.operator {
+                AssignmentOperator::Equal => {
+                    type_definition.inner().check(&statement_type)?;
+                }
+                AssignmentOperator::PlusEqual => {
+                    if let Type::List(item_type) = type_definition.inner() {
+                        item_type.check(&statement_type)?;
+                    } else {
+                        type_definition
+                            .inner()
+                            .check(&self.identifier.expected_type(context)?)?;
+                    }
+                }
+                AssignmentOperator::MinusEqual => todo!(),
+            }
+        } else {
+            match self.operator {
+                AssignmentOperator::Equal => {}
+                AssignmentOperator::PlusEqual => {
+                    if let Type::List(item_type) = self.identifier.expected_type(context)? {
+                        item_type.check(&statement_type)?;
+                    }
+                }
+                AssignmentOperator::MinusEqual => todo!(),
+            }
+        }
+
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         let key = self.identifier.inner();
         let value = self.statement.run(source, context)?;

src/abstract_tree/block.rs

@@ -50,6 +50,18 @@ impl AbstractTree for Block {
         })
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        for statement in &self.statements {
+            if let Statement::Return(inner_statement) = statement {
+                return inner_statement.check_type(_source, _context);
+            } else {
+                statement.check_type(_source, _context)?;
+            }
+        }
+
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         if self.is_async {
             let statements = &self.statements;

src/abstract_tree/built_in_value.rs

@@ -140,6 +140,10 @@ impl AbstractTree for BuiltInValue {
         Ok(built_in_value)
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
         Ok(self.get().clone())
     }

src/abstract_tree/expression.rs

@@ -65,27 +65,39 @@ impl AbstractTree for Expression {
         Ok(expression)
     }
 
-    fn run(&self, source: &str, context: &Map) -> Result<Value> {
+    fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
         match self {
-            Expression::Value(value_node) => value_node.run(source, context),
-            Expression::Identifier(identifier) => identifier.run(source, context),
-            Expression::Math(math) => math.run(source, context),
-            Expression::Logic(logic) => logic.run(source, context),
-            Expression::FunctionCall(function_call) => function_call.run(source, context),
-            Expression::Index(index) => index.run(source, context),
-            Expression::Yield(r#yield) => r#yield.run(source, context),
+            Expression::Value(value_node) => value_node.run(_source, _context),
+            Expression::Identifier(identifier) => identifier.run(_source, _context),
+            Expression::Math(math) => math.run(_source, _context),
+            Expression::Logic(logic) => logic.run(_source, _context),
+            Expression::FunctionCall(function_call) => function_call.run(_source, _context),
+            Expression::Index(index) => index.run(_source, _context),
+            Expression::Yield(r#yield) => r#yield.run(_source, _context),
         }
     }
 
-    fn expected_type(&self, context: &Map) -> Result<Type> {
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
         match self {
-            Expression::Value(value_node) => value_node.expected_type(context),
-            Expression::Identifier(identifier) => identifier.expected_type(context),
-            Expression::Math(math) => math.expected_type(context),
-            Expression::Logic(logic) => logic.expected_type(context),
-            Expression::FunctionCall(function_call) => function_call.expected_type(context),
-            Expression::Index(index) => index.expected_type(context),
-            Expression::Yield(r#yield) => r#yield.expected_type(context),
+            Expression::Value(value_node) => value_node.check_type(_source, _context),
+            Expression::Identifier(identifier) => identifier.check_type(_source, _context),
+            Expression::Math(math) => math.check_type(_source, _context),
+            Expression::Logic(logic) => logic.check_type(_source, _context),
+            Expression::FunctionCall(function_call) => function_call.check_type(_source, _context),
+            Expression::Index(index) => index.check_type(_source, _context),
+            Expression::Yield(r#yield) => r#yield.check_type(_source, _context),
+        }
+    }
+
+    fn expected_type(&self, _context: &Map) -> Result<Type> {
+        match self {
+            Expression::Value(value_node) => value_node.expected_type(_context),
+            Expression::Identifier(identifier) => identifier.expected_type(_context),
+            Expression::Math(math) => math.expected_type(_context),
+            Expression::Logic(logic) => logic.expected_type(_context),
+            Expression::FunctionCall(function_call) => function_call.expected_type(_context),
+            Expression::Index(index) => index.expected_type(_context),
+            Expression::Yield(r#yield) => r#yield.expected_type(_context),
         }
     }
 }

src/abstract_tree/for.rs

@@ -74,6 +74,10 @@ impl AbstractTree for For {
         Ok(Value::none())
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, _context: &Map) -> Result<Type> {
         Ok(Type::None)
     }

src/abstract_tree/function_call.rs

@@ -25,9 +25,7 @@ impl AbstractTree for FunctionCall {
         let function_node = node.child(0).unwrap();
         let function_expression =
             FunctionExpression::from_syntax_node(source, function_node, context)?;
-        let function_type = function_expression.expected_type(context)?;
 
-        let mut minimum_parameter_count = 0;
         let mut arguments = Vec::new();
 
         for index in 2..node.child_count() - 1 {
@@ -35,48 +33,53 @@ impl AbstractTree for FunctionCall {
 
             if child.is_named() {
                 let expression = Expression::from_syntax_node(source, child, context)?;
-                let expression_type = expression.expected_type(context)?;
-                let argument_index = arguments.len();
-
-                if let Type::Function {
-                    parameter_types, ..
-                } = &function_type
-                {
-                    if let Some(r#type) = parameter_types.get(argument_index) {
-                        if let Type::Option(_) = r#type {
-                        } else {
-                            minimum_parameter_count += 1;
-                        }
-
-                        r#type
-                            .check(&expression_type)
-                            .map_err(|error| error.at_node(child, source))?;
-                    }
-                }
 
                 arguments.push(expression);
             }
         }
 
-        if let Type::Function {
-            parameter_types: _, ..
-        } = &function_type
-        {
-            if arguments.len() < minimum_parameter_count {
-                return Err(Error::ExpectedFunctionArgumentMinimum {
-                    source: source[function_node.byte_range()].to_string(),
-                    minumum_expected: minimum_parameter_count,
-                    actual: arguments.len(),
-                });
-            }
-        }
-
         Ok(FunctionCall {
             function_expression,
             arguments,
         })
     }
 
+    fn check_type(&self, _source: &str, context: &Map) -> Result<()> {
+        let function_type = self.function_expression.expected_type(context)?;
+        let mut minimum_parameter_count = 0;
+
+        for (index, expression) in self.arguments.iter().enumerate() {
+            if let Type::Function {
+                parameter_types, ..
+            } = &function_type
+            {
+                if let Some(r#type) = parameter_types.get(index) {
+                    if let Type::Option(_) = r#type {
+                    } else {
+                        minimum_parameter_count += 1;
+                    }
+
+                    r#type.check(&expression.expected_type(context)?)?;
+                }
+            }
+        }
+
+        if let Type::Function {
+            parameter_types: _, ..
+        } = &function_type
+        {
+            if self.arguments.len() < minimum_parameter_count {
+                return Err(Error::ExpectedFunctionArgumentMinimum {
+                    source: "TODO".to_string(),
+                    minumum_expected: minimum_parameter_count,
+                    actual: self.arguments.len(),
+                });
+            }
+        }
+
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         let (name, value) = match &self.function_expression {
             FunctionExpression::Identifier(identifier) => {

src/abstract_tree/function_expression.rs

@@ -64,6 +64,10 @@ impl AbstractTree for FunctionExpression {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         match self {
             FunctionExpression::Identifier(identifier) => identifier.expected_type(context),

src/abstract_tree/identifier.rs

@@ -43,6 +43,10 @@ impl AbstractTree for Identifier {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         if let Some((_value, r#type)) = context.variables()?.get(&self.0) {
             Ok(r#type.clone())

src/abstract_tree/if_else.rs

@@ -81,6 +81,10 @@ impl AbstractTree for IfElse {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         self.if_block.expected_type(context)
     }

src/abstract_tree/index.rs

@@ -89,6 +89,10 @@ impl AbstractTree for Index {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         match self.collection.expected_type(context)? {
             Type::List(item_type) => Ok(*item_type.clone()),

src/abstract_tree/index_assignment.rs

@@ -91,6 +91,10 @@ impl AbstractTree for IndexAssignment {
         Ok(Value::none())
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, _context: &Map) -> Result<Type> {
         Ok(Type::None)
     }

src/abstract_tree/index_expression.rs

@@ -48,6 +48,10 @@ impl AbstractTree for IndexExpression {
         Ok(abstract_node)
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         match self {
             IndexExpression::Value(value_node) => value_node.run(source, context),

src/abstract_tree/logic.rs

@@ -88,6 +88,10 @@ impl AbstractTree for Logic {
         Ok(Value::Boolean(result))
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, _context: &Map) -> Result<Type> {
         Ok(Type::Boolean)
     }

src/abstract_tree/match.rs

@@ -76,6 +76,10 @@ impl AbstractTree for Match {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         let (_, first_statement) = self.options.first().unwrap();
 

src/abstract_tree/math.rs

@@ -62,6 +62,10 @@ impl AbstractTree for Math {
         Ok(value)
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         self.left.expected_type(context)
     }

src/abstract_tree/mod.rs

@@ -59,6 +59,18 @@ impl AbstractTree for Root {
         Ok(Root { statements })
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        for statement in &self.statements {
+            if let Statement::Return(inner_statement) = statement {
+                return inner_statement.check_type(_source, _context);
+            } else {
+                statement.check_type(_source, _context)?;
+            }
+        }
+
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         let mut value = Value::none();
 
@@ -95,5 +107,8 @@ pub trait AbstractTree: Sized {
     /// Execute dust code by traversing the tree.
     fn run(&self, source: &str, context: &Map) -> Result<Value>;
 
+    /// Verify the type compatibility of this node.
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()>;
+
     fn expected_type(&self, context: &Map) -> Result<Type>;
 }

src/abstract_tree/statement.rs

@@ -80,6 +80,22 @@ impl AbstractTree for Statement {
         }
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        match self {
+            Statement::Assignment(assignment) => assignment.check_type(_source, _context),
+            Statement::Expression(expression) => expression.check_type(_source, _context),
+            Statement::IfElse(if_else) => if_else.check_type(_source, _context),
+            Statement::Match(r#match) => r#match.check_type(_source, _context),
+            Statement::While(r#while) => r#while.check_type(_source, _context),
+            Statement::Block(block) => block.check_type(_source, _context),
+            Statement::For(r#for) => r#for.check_type(_source, _context),
+            Statement::IndexAssignment(index_assignment) => {
+                index_assignment.check_type(_source, _context)
+            }
+            Statement::Return(statement) => statement.check_type(_source, _context),
+        }
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         match self {
             Statement::Assignment(assignment) => assignment.expected_type(context),

src/abstract_tree/type_definition.rs

@@ -38,6 +38,10 @@ impl AbstractTree for TypeDefinition {
         self.r#type.run(source, context)
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        self.r#type.check_type(_source, _context)
+    }
+
     fn expected_type(&self, context: &Map) -> Result<Type> {
         self.r#type.expected_type(context)
     }
@@ -239,6 +243,10 @@ impl AbstractTree for Type {
         Ok(r#type)
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        Ok(())
+    }
+
     fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
         Ok(Value::none())
     }

src/abstract_tree/value_node.rs

@@ -77,10 +77,6 @@ impl AbstractTree for ValueNode {
                         let statement =
                             Statement::from_syntax_node(source, child_syntax_node, context)?;
 
-                        if let Some(type_definition) = &current_type {
-                            type_definition.check(&statement.expected_type(context)?)?;
-                        }
-
                         child_nodes.insert(current_key.clone(), (statement, current_type.clone()));
                     }
                 }
@@ -122,6 +118,38 @@ impl AbstractTree for ValueNode {
         Ok(value_node)
     }
 
+    fn check_type(&self, _source: &str, context: &Map) -> Result<()> {
+        match self {
+            ValueNode::Function(function) => function.check_type(_source, context)?,
+            ValueNode::List(expression_list) => {
+                for expression in expression_list {
+                    expression.check_type(_source, context)?;
+                }
+            }
+            ValueNode::BuiltInValue(built_in_value) => {
+                built_in_value.check_type(_source, context)?
+            }
+            ValueNode::Map(map) => {
+                for (_, (statement, r#type)) in map {
+                    statement.check_type(_source, context)?;
+
+                    if let Some(r#type) = r#type {
+                        r#type.check_type(_source, context)?;
+                        r#type.check(&statement.expected_type(context)?)?;
+                    }
+                }
+            }
+            ValueNode::Option(option) => {
+                if let Some(expression) = option {
+                    expression.check_type(_source, context)?;
+                }
+            }
+            _ => {}
+        }
+
+        Ok(())
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         let value = match self {
             ValueNode::Boolean(value_source) => Value::Boolean(value_source.parse().unwrap()),

src/abstract_tree/while.rs

@@ -25,6 +25,11 @@ impl AbstractTree for While {
         Ok(While { expression, block })
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        self.expression.check_type(_source, _context)?;
+        self.block.check_type(_source, _context)
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         while self.expression.run(source, context)?.as_boolean()? {
             self.block.run(source, context)?;

src/abstract_tree/yield.rs

@@ -44,6 +44,10 @@ impl AbstractTree for Yield {
         Ok(Yield { call })
     }
 
+    fn check_type(&self, _source: &str, _context: &Map) -> Result<()> {
+        self.call.check_type(_source, _context)
+    }
+
     fn run(&self, source: &str, context: &Map) -> Result<Value> {
         self.call.run(source, context)
     }

src/interpret.rs

@@ -115,6 +115,7 @@ impl Interpreter {
         };
 
         if let Some(abstract_tree) = &self.abstract_tree {
+            abstract_tree.check_type(source, &self.context)?;
             abstract_tree.run(source, &self.context)
         } else {
             Ok(Value::none())

src/value/function.rs

@@ -93,11 +93,6 @@ impl AbstractTree for Function {
         let body_node = node.child(child_count - 1).unwrap();
         let body = Block::from_syntax_node(source, body_node, &function_context)?;
 
-        return_type
-            .inner()
-            .check(&body.expected_type(&function_context)?)
-            .map_err(|error| error.at_node(body_node, source))?;
-
         let r#type = Type::function(parameter_types, return_type.take_inner());
 
         Ok(Self::ContextDefined(ContextDefinedFunction::new(
@@ -105,6 +100,19 @@ impl AbstractTree for Function {
         )))
     }
 
+    fn check_type(&self, _source: &str, context: &Map) -> Result<()> {
+        match self {
+            Function::BuiltIn(_built_in_function) => {}
+            Function::ContextDefined(function) => {
+                function
+                    .return_type()
+                    .check(&function.body.expected_type(&context)?)?;
+            }
+        }
+
+        Ok(())
+    }
+
     fn run(&self, _source: &str, _context: &Map) -> Result<Value> {
         Ok(Value::Function(self.clone()))
     }