🌟 completed classes

aym-n · Jan 10, 2024 · e7cfc79 · e7cfc79
1 parent 1d47f8d
commit e7cfc79
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Showing 6 changed files with 63 additions and 12 deletions.
diff --git a/main.arc b/main.arc
@@ -1,7 +1,9 @@
-class Bacon {
-  eat() {
-    print "Crunch crunch crunch!";
+class Foo {
+  init() {
+    print this;
+    return 10;
   }
 }
 
-Bacon().eat();
+var foo = Foo();
+print foo.init();
diff --git a/src/errors.rs b/src/errors.rs
@@ -1,5 +1,6 @@
 use crate::tokens::*;
 
+#[derive(Debug, PartialEq, Clone)]
 pub enum Error {
     ParseError { token: Token, message: String },
     RuntimeError { token: Token, message: String },

diff --git a/src/functions.rs b/src/functions.rs
@@ -12,6 +12,7 @@ use crate::interpreter::Interpreter;
 pub struct Function {
     name : Token,
     params : Rc<Vec<Token>>,
+    is_initializer: bool,
     body : Rc<Vec<Rc<Stmt>>>,
     closure: Rc<RefCell<Environment>>,
 }
@@ -26,6 +27,7 @@ impl Clone for Function {
     fn clone(&self) -> Self {
         Self {
             name: self.name.clone(),
+            is_initializer: self.is_initializer,
             params: Rc::clone(&self.params),
             body: Rc::clone(&self.body),
             closure: Rc::clone(&self.closure),
@@ -40,12 +42,13 @@ impl PartialEq for Function {
 }
 
 impl Function {
-    pub fn new(declaration: &FunctionStmt, closure: &Rc<RefCell<Environment>>) -> Self {
+    pub fn new(declaration: &FunctionStmt, closure: &Rc<RefCell<Environment>>, is_initializer: bool) -> Self {
         Self {
             name: declaration.name.clone(),
             params: Rc::clone(&declaration.params),
             body: Rc::clone(&declaration.body),
             closure: Rc::clone(&closure),
+            is_initializer: is_initializer,
         }
     }
 
@@ -54,6 +57,7 @@ impl Function {
         e.borrow_mut().define("this".to_string(), instance.clone());
         Object::Function(Rc::new(Self {
             name: self.name.clone(),
+            is_initializer: self.is_initializer,
             params: Rc::clone(&self.params),
             body: Rc::clone(&self.body),
             closure: Rc::new(e),
@@ -71,10 +75,19 @@ impl CallableTrait for Function {
         }
 
         match interpreter.execute_block(&self.body, e) {
-            Ok(_) => Ok(Object::Nil),
+            Ok(_) => {
+                if self.is_initializer {
+                    return Ok(self.closure.borrow().get_at(0, "this").unwrap());
+                }
+                Ok(Object::Nil)
+            }
             Err(e) => {
                 match e {
-                    Error::Return { value } => Ok(value),
+                    Error::Return { value } => if self.is_initializer {
+                        Ok(self.closure.borrow().get_at(0, "this").unwrap())
+                    } else {
+                        Ok(value)
+                    }
                     _ => Err(e),
                 }
             }

diff --git a/src/interpreter.rs b/src/interpreter.rs
@@ -28,8 +28,9 @@ impl StmtVisitor<()> for Interpreter {
         let mut methods = HashMap::new();
         for method in stmt.methods.deref() {
             if let Stmt::Function(func) = method.deref() {
+                let is_initializer = func.name.lexeme == "init";
                 let function = Object::Function(Rc::new(
-                    Function::new(func, self.environment.borrow().deref()),
+                    Function::new(func, self.environment.borrow().deref(), is_initializer),
                 ));
                 methods.insert(func.name.lexeme.clone(), function);
             } else {
@@ -58,7 +59,7 @@ impl StmtVisitor<()> for Interpreter {
         }
     }
     fn visit_function_stmt(&self, _: Rc<Stmt>, stmt: &FunctionStmt) -> Result<(), Error> {
-        let function = Function::new(stmt, self.environment.borrow().deref());
+        let function = Function::new(stmt, self.environment.borrow().deref(), false);
         self.environment.borrow().borrow_mut().define(
             stmt.name.lexeme.clone(),
             Object::Function(Rc::new(function)),

diff --git a/src/resolver.rs b/src/resolver.rs
@@ -14,33 +14,50 @@ pub struct Resolver<'a>{
     scopes: RefCell<Vec<RefCell<HashMap<String, bool>>>>,
     had_error: RefCell<bool>,
     current_function: RefCell<FunctionType>,
+    current_class: RefCell<ClassType>,
 }
 
 #[derive(PartialEq)]
 enum FunctionType {
     None,
     Function,
+    Initializer,
     Method,
 }
 
+#[derive(PartialEq)]
+enum ClassType {
+    None,
+    Class,
+}
+
+
 impl<'a> StmtVisitor<()> for Resolver<'a>{
     fn visit_class_stmt(&self , _: Rc<Stmt>, stmt: &ClassStmt) -> Result<(), Error> {
+
+        let enclosing_class = self.current_class.replace(ClassType::Class);
+
         self.declare(&stmt.name);
         self.define(&stmt.name);
 
         self.begin_scope();
         self.scopes.borrow().last().unwrap().borrow_mut().insert("this".to_string(), true);
 
         for method in stmt.methods.deref() {
-            let declaration = FunctionType::Method;
             if let Stmt::Function(method) = method.deref() {
+                let declaration = if method.name.lexeme == "init" {
+                    FunctionType::Initializer
+                }else{
+                    FunctionType::Method
+                };
                 self.resolve_function(method, declaration);
             }else{
                 return Err(Error::runtime_error(&stmt.name, "Class method did not resolve to a function."));
             }
         }
 
         self.end_scope();
+        self.current_class.replace(enclosing_class);
 
         Ok(())
     }
@@ -51,6 +68,9 @@ impl<'a> StmtVisitor<()> for Resolver<'a>{
         }
 
         if let Some(value) = stmt.value.clone() {
+            if *self.current_function.borrow() == FunctionType::Initializer {
+                return Err(Error::runtime_error(&stmt.keyword, "Cannot return a value from an initializer."));
+            }
             self.resolve_expr(value);
         }
 
@@ -104,6 +124,10 @@ impl<'a> StmtVisitor<()> for Resolver<'a>{
 
 impl<'a> ExprVisitor<()> for Resolver<'a>{
     fn visit_this_expr(&self, wrapper: Rc<Expr>, expr: &ThisExpr) -> Result<(), Error> {
+        if *self.current_class.borrow() == ClassType::None {
+            self.error(&expr.keyword, "Cannot use 'this' outside of a class.");
+            return Ok(());   
+        }
         self.resolve_local(wrapper, &expr.keyword);
         Ok(())
     }
@@ -173,6 +197,7 @@ impl<'a> Resolver<'a> {
             scopes: RefCell::new(Vec::new()),
             had_error: RefCell::new(false),
             current_function: RefCell::new(FunctionType::None),
+            current_class: RefCell::new(ClassType::None),
         }
     }
     pub fn resolve(&self, statement: &Rc<Vec<Rc<Stmt>>>){

diff --git a/src/tokens.rs b/src/tokens.rs
@@ -113,8 +113,14 @@ impl ClassStruct {
         }
     }
 
-    pub fn instantiate(&self, _interpreter: &Interpreter, _arguments: Vec<Object>, cls: Rc<ClassStruct>) -> Result<Object, Error> {
-        Ok(Object::Instance(Rc::new(InstanceStruct::new(cls))))
+    pub fn instantiate(&self, interpreter: &Interpreter, arguments: Vec<Object>, cls: Rc<ClassStruct>) -> Result<Object, Error> {
+        let instance = Object::Instance(Rc::new(InstanceStruct::new(cls)));
+        if let Some(Object::Function(initializer)) = self.find_method("init".to_string()){
+            if let Object::Function(initializer) = initializer.bind(&instance) {
+                initializer.call(interpreter, &arguments)?;
+            }
+        }
+        Ok(instance)
     }
 
     pub fn find_method(&self, name: String) -> Option<Object> {
@@ -128,6 +134,9 @@ impl CallableTrait for ClassStruct {
     }
 
     fn arity(&self) -> usize {
+        if let Some(Object::Function(initializer)) = self.find_method("init".to_string()){
+            return initializer.arity();
+        }
         0
     }