Chapter 12, Sections 1, 2, and 3

1 files changed, 31 insertions, 0 deletions

diff --git a/src/com/craftinginterpreters/lox/Interpreter.java b/src/com/craftinginterpreters/lox/Interpreter.java
index 4092191..5c1ea50 100644
--- a/src/com/craftinginterpreters/lox/Interpreter.java
+++ b/src/com/craftinginterpreters/lox/Interpreter.java
@@ -50,6 +50,19 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
     }
 
     @Override
+    public Object visitSetExpr(Expr.Set expr) {
+        Object object = evaluate(expr.object);
+
+        if (!(object instanceof LoxInstance)) {
+            throw new RuntimeError(expr.name, "Only instances have fields.");
+        }
+
+        Object value = evaluate(expr.value);
+        ((LoxInstance) object).set(expr.name, value);
+        return value;
+    }
+
+    @Override
     public Object visitUnaryExpr(Expr.Unary expr) {
         Object right = evaluate(expr.right);
 
@@ -162,6 +175,14 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
     }
 
     @Override
+    public Void visitClassStmt(Stmt.Class stmt) {
+        environment.define(stmt.name.lexeme, null);
+        LoxClass klass = new LoxClass(stmt.name.lexeme);
+        environment.assign(stmt.name, klass);
+        return null;
+    }
+
+    @Override
     public Void visitExpressionStmt(Stmt.Expression stmt) {
         evaluate(stmt.expression);
         return null;
@@ -304,6 +325,16 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
         return function.call(this, arguments);
     }
 
+    @Override
+    public Object visitGetExpr(Expr.Get expr) {
+        Object object = evaluate(expr.object);
+        if (object instanceof LoxInstance) {
+            return ((LoxInstance) object).get(expr.name);
+        }
+
+        throw new RuntimeError(expr.name, "Only instances have properties.");
+    }
+
     public void interpret(List<Stmt> statements) {
         try {
             for (Stmt statement : statements) {