Add branching primitives

1 files changed, 24 insertions, 0 deletions

diff --git a/src/com/craftinginterpreters/lox/Interpreter.java b/src/com/craftinginterpreters/lox/Interpreter.java
index e03ca37..6c32233 100644
--- a/src/com/craftinginterpreters/lox/Interpreter.java
+++ b/src/com/craftinginterpreters/lox/Interpreter.java
@@ -11,6 +11,19 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
     }
 
     @Override
+    public Object visitLogicalExpr(Expr.Logical expr) {
+        Object left = evaluate(expr.left);
+
+        if (expr.operator.type == TokenType.OR) {
+            if (isTruthy(left)) return left;
+        } else {
+            if (!isTruthy(left)) return left;
+        }
+
+        return evaluate(expr.right);
+    }
+
+    @Override
     public Object visitUnaryExpr(Expr.Unary expr) {
         Object right = evaluate(expr.right);
 
@@ -116,6 +129,17 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
     }
 
     @Override
+    public Void visitIfStmt(Stmt.If stmt) {
+        if (isTruthy(evaluate(stmt.condition))) {
+            execute(stmt.thenBranch);
+        } else if (stmt.elseBranch != null) {
+            execute(stmt.elseBranch);
+        }
+
+        return null;
+    }
+
+    @Override
     public Void visitPrintStmt(Stmt.Print stmt) {
         Object value = evaluate(stmt.expression);
         System.out.println(stringify(value));