Set and retrieve attributes on instances.

vm/src/bytecode.rs

@@ -38,6 +38,7 @@ pub enum Instruction {
     LoadName { name: String },
     StoreName { name: String },
     StoreSubscript,
+    StoreAttr { name: String },
     LoadConst { value: Constant },
     UnaryOperation { op: UnaryOperator },
     BinaryOperation { op: BinaryOperator },

vm/src/compile.rs

@@ -351,8 +351,14 @@ impl Compiler {
                 self.compile_expression(b);
                 self.emit(Instruction::StoreSubscript);
             }
+            ast::Expression::Attribute { value, name } => {
+                self.compile_expression(value);
+                self.emit(Instruction::StoreAttr {
+                    name: name.to_string()
+                });
+            }
             _ => {
-                panic!("WTF");
+                panic!("WTF: {:?}", target);
             }
         }
     }

vm/src/pyobject.rs

@@ -210,6 +210,7 @@ impl ParentProtocol for PyObjectRef {
 
 pub trait AttributeProtocol {
     fn get_attr(&self, attr_name: &String) -> PyObjectRef;
+    fn set_attr(&self, attr_name: &String, value: PyObjectRef);
 }
 
 impl AttributeProtocol for PyObjectRef {
@@ -221,6 +222,14 @@ impl AttributeProtocol for PyObjectRef {
             ref kind => unimplemented!("load_attr unimplemented for: {:?}", kind),
         }
     }
+
+    fn set_attr(&self, attr_name: &String, value: PyObjectRef) {
+        match self.borrow_mut().kind {
+            PyObjectKind::Instance { ref mut dict } =>
+                dict.set_item(attr_name, value),
+            ref kind => unimplemented!("load_attr unimplemented for: {:?}", kind),
+        };
+    }
 }
 
 pub trait DictProtocol {

vm/src/vm.rs

@@ -483,7 +483,7 @@ impl VirtualMachine {
         let init = type_ref.get_attr(&String::from("__init__"));
         let mut self_args = PyFuncArgs { args: args.args };
         self_args.args.insert(0, obj.clone());
-        self.invoke(init, self_args);
+        self.invoke(init, self_args).unwrap();
         Ok(obj)
     }
 
@@ -527,6 +527,13 @@ impl VirtualMachine {
         None
     }
 
+    fn store_attr(&mut self, attr_name: &String) -> Option<PyResult> {
+        let parent = self.pop_value();
+        let value = self.pop_value();
+        parent.set_attr(attr_name, value);
+        None
+    }
+
     // Execute a single instruction:
     fn execute_instruction(&mut self) -> Option<PyResult> {
         let instruction = self.current_frame().fetch_instruction();
@@ -629,6 +636,7 @@ impl VirtualMachine {
             }
             bytecode::Instruction::BinaryOperation { ref op } => self.execute_binop(op),
             bytecode::Instruction::LoadAttr { ref name } => self.load_attr(name),
+            bytecode::Instruction::StoreAttr { ref name } => self.store_attr(name),
             bytecode::Instruction::UnaryOperation { ref op } => self.execute_unop(op),
             bytecode::Instruction::CompareOperation { ref op } => self.execute_compare(op),
             bytecode::Instruction::ReturnValue => {