Fix function contexts and recursion

src/abstract_tree/function_call.rs

@@ -13,9 +13,6 @@ pub struct FunctionCall {
     function_expression: FunctionExpression,
     arguments: Vec<Expression>,
     syntax_position: SourcePosition,
-
-    #[serde(skip)]
-    context: Context,
 }
 
 impl FunctionCall {
@@ -24,13 +21,11 @@ impl FunctionCall {
         function_expression: FunctionExpression,
         arguments: Vec<Expression>,
         syntax_position: SourcePosition,
-        context: Context,
     ) -> Self {
         Self {
             function_expression,
             arguments,
             syntax_position,
-            context,
         }
     }
 }
@@ -58,7 +53,6 @@ impl AbstractTree for FunctionCall {
             function_expression,
             arguments,
             syntax_position: node.range().into(),
-            context: Context::new(),
         })
     }
 
@@ -143,7 +137,6 @@ impl AbstractTree for FunctionCall {
         let value = match &self.function_expression {
             FunctionExpression::Identifier(identifier) => {
                 if let Some(value) = context.get_value(identifier)? {
-                    self.context.set_value(identifier.clone(), value.clone())?;
                     value.clone()
                 } else {
                     return Err(RuntimeError::VariableIdentifierNotFound(identifier.clone()));
@@ -167,19 +160,25 @@ impl AbstractTree for FunctionCall {
                     arguments.push(value);
                 }
 
-                built_in_function.call(&arguments, source, &self.context)
+                built_in_function.call(&arguments, source, context)
             }
             Function::ContextDefined(function_node) => {
+                let call_context = Context::with_variables_from(function_node.context())?;
+
+                call_context.inherit_from(context)?;
+
                 let parameter_expression_pairs =
                     function_node.parameters().iter().zip(self.arguments.iter());
 
                 for (identifier, expression) in parameter_expression_pairs {
                     let value = expression.run(source, context)?;
 
-                    self.context.set_value(identifier.clone(), value)?;
+                    call_context.set_value(identifier.clone(), value)?;
                 }
 
-                function_node.call(source, &self.context)
+                println!("{}", call_context);
+
+                function_node.body().run(source, &call_context)
             }
         }
     }

src/abstract_tree/function_node.rs

@@ -14,23 +14,12 @@ pub struct FunctionNode {
     body: Block,
     r#type: Type,
     syntax_position: SourcePosition,
+
+    #[serde(skip)]
+    context: Context,
 }
 
 impl FunctionNode {
-    pub fn new(
-        parameters: Vec<Identifier>,
-        body: Block,
-        r#type: Type,
-        syntax_position: SourcePosition,
-    ) -> Self {
-        FunctionNode {
-            parameters,
-            body,
-            r#type,
-            syntax_position,
-        }
-    }
-
     pub fn parameters(&self) -> &Vec<Identifier> {
         &self.parameters
     }
@@ -47,6 +36,10 @@ impl FunctionNode {
         &self.syntax_position
     }
 
+    pub fn context(&self) -> &Context {
+        &self.context
+    }
+
     pub fn return_type(&self) -> &Type {
         match &self.r#type {
             Type::Function {
@@ -56,12 +49,6 @@ impl FunctionNode {
             _ => &Type::None,
         }
     }
-
-    pub fn call(&self, source: &str, context: &Context) -> Result<Value, RuntimeError> {
-        let return_value = self.body.run(source, context)?;
-
-        Ok(return_value)
-    }
 }
 
 impl AbstractTree for FunctionNode {
@@ -91,8 +78,10 @@ impl AbstractTree for FunctionNode {
         let return_type_node = node.child(child_count - 2).unwrap();
         let return_type = TypeSpecification::from_syntax(return_type_node, source, context)?;
 
+        let function_context = Context::with_variables_from(context)?;
+
         let body_node = node.child(child_count - 1).unwrap();
-        let body = Block::from_syntax(body_node, source, &context)?;
+        let body = Block::from_syntax(body_node, source, &function_context)?;
 
         let r#type = Type::function(parameter_types, return_type.take_inner());
         let syntax_position = node.range().into();
@@ -102,6 +91,7 @@ impl AbstractTree for FunctionNode {
             body,
             r#type,
             syntax_position,
+            context: function_context,
         })
     }
 
@@ -109,19 +99,19 @@ impl AbstractTree for FunctionNode {
         Ok(self.r#type().clone())
     }
 
-    fn validate(&self, source: &str, _context: &Context) -> Result<(), ValidationError> {
+    fn validate(&self, source: &str, context: &Context) -> Result<(), ValidationError> {
         if let Type::Function {
             parameter_types,
             return_type,
         } = &self.r#type
         {
-            let validation_context = Context::new();
+            self.context.inherit_from(context)?;
 
             for (parameter, r#type) in self.parameters.iter().zip(parameter_types.iter()) {
-                validation_context.set_type(parameter.clone(), r#type.clone())?;
+                self.context.set_type(parameter.clone(), r#type.clone())?;
             }
 
-            let actual = self.body.expected_type(&validation_context)?;
+            let actual = self.body.expected_type(&self.context)?;
 
             if !return_type.accepts(&actual) {
                 return Err(ValidationError::TypeCheck {
@@ -131,7 +121,7 @@ impl AbstractTree for FunctionNode {
                 });
             }
 
-            self.body.validate(source, &validation_context)?;
+            self.body.validate(source, &self.context)?;
 
             Ok(())
         } else {
@@ -142,7 +132,9 @@ impl AbstractTree for FunctionNode {
         }
     }
 
-    fn run(&self, _source: &str, _context: &Context) -> Result<Value, RuntimeError> {
+    fn run(&self, _source: &str, context: &Context) -> Result<Value, RuntimeError> {
+        self.context.inherit_from(context)?;
+
         let self_as_value = Value::Function(Function::ContextDefined(self.clone()));
 
         Ok(self_as_value)

src/abstract_tree/identifier.rs

@@ -59,8 +59,12 @@ impl AbstractTree for Identifier {
         Ok(Identifier::new(text))
     }
 
-    fn validate(&self, _source: &str, _context: &Context) -> Result<(), ValidationError> {
+    fn validate(&self, _source: &str, context: &Context) -> Result<(), ValidationError> {
-        Ok(())
+        if let Some(_) = context.get_type(self)? {
+            Ok(())
+        } else {
+            Err(ValidationError::VariableIdentifierNotFound(self.clone()))
+        }
     }
 
     fn expected_type(&self, context: &Context) -> Result<Type, ValidationError> {

src/context.rs

@@ -30,6 +30,7 @@
 use std::{
     cmp::Ordering,
     collections::BTreeMap,
+    fmt::Display,
     sync::{Arc, RwLock, RwLockReadGuard},
 };
 
@@ -73,7 +74,7 @@ impl Context {
         })
     }
 
-    /// Modify a context to take on all of the key-value pairs of another.
+    /// Modify a context to take the functions and type definitions of another.
     ///
     /// In the case of the conflict, the inherited value will override the previous
     /// value.
@@ -96,11 +97,19 @@ impl Context {
         let mut self_variables = self.inner.write()?;
 
         for (identifier, value_data) in other.inner.read()?.iter() {
-            let existing_data = self_variables.get(identifier);
+            if let ValueData::Value { inner, .. } = value_data {
+                if inner.is_function() {
+                    self_variables.insert(identifier.clone(), value_data.clone());
+                }
+            }
 
-            if let Some(ValueData::Value { .. }) = existing_data {
+            if let ValueData::TypeHint { inner } = value_data {
-                continue;
+                if inner.is_function() {
-            } else {
+                    self_variables.insert(identifier.clone(), value_data.clone());
+                }
+            }
+
+            if let ValueData::TypeDefinition(_) = value_data {
                 self_variables.insert(identifier.clone(), value_data.clone());
             }
         }
@@ -120,7 +129,6 @@ impl Context {
         }
 
         for built_in_value in all_built_in_values() {
-            println!("{} {}", built_in_value.name(), identifier.inner());
             if built_in_value.name() == identifier.inner().as_ref() {
                 return Ok(Some(built_in_value.get().clone()));
             }
@@ -176,6 +184,8 @@ impl Context {
 
     /// Set a value to a key.
     pub fn set_value(&self, key: Identifier, value: Value) -> Result<(), RwLockError> {
+        log::info!("Setting value: {key} = {value}");
+
         self.inner.write()?.insert(
             key,
             ValueData::Value {
@@ -192,6 +202,8 @@ impl Context {
     /// This allows the interpreter to check a value's type before the value
     /// actually exists by predicting what the abstract tree will produce.
     pub fn set_type(&self, key: Identifier, r#type: Type) -> Result<(), RwLockError> {
+        log::info!("Setting type: {key} <{}>", r#type);
+
         self.inner
             .write()?
             .insert(key, ValueData::TypeHint { inner: r#type });
@@ -339,3 +351,15 @@ impl Ord for ValueData {
         }
     }
 }
+
+impl Display for Context {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        writeln!(f, "{{")?;
+
+        for (identifier, value_data) in self.inner.read().unwrap().iter() {
+            writeln!(f, "{identifier} {value_data:?}")?;
+        }
+
+        writeln!(f, "}}")
+    }
+}

tests/functions.rs

@@ -5,9 +5,9 @@ fn function_call() {
     assert_eq!(
         interpret(
             "
-                foobar = (message <str>) <str> { message }
+            foobar = (message <str>) <str> { message }
-                foobar('Hiya')
+            foobar('Hiya')
-                ",
+            ",
         ),
         Ok(Value::string("Hiya".to_string()))
     );
@@ -18,9 +18,9 @@ fn call_empty_function() {
     assert_eq!(
         interpret(
             "
-                foobar = (message <str>) <none> {}
+            foobar = (message <str>) <none> {}
-                foobar('Hiya')
+            foobar('Hiya')
-                ",
+            ",
         ),
         Ok(Value::none())
     );
@@ -96,7 +96,7 @@ fn function_context_captures_structure_definitions() {
     assert_eq!(
         interpret(
             "
-            User = struct {
+            struct User {
                 name <str>
             }