From ca9fd3ae3a1ef5ca1fbe33a83abb12e656a2556f Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Wed, 25 Nov 2020 23:10:58 -0800
Subject: Chapter 8: Add blocks and scopes

---
 src/com/craftinginterpreters/lox/Interpreter.java | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'src/com/craftinginterpreters/lox/Interpreter.java')

diff --git a/src/com/craftinginterpreters/lox/Interpreter.java b/src/com/craftinginterpreters/lox/Interpreter.java
index 7378164..e03ca37 100644
--- a/src/com/craftinginterpreters/lox/Interpreter.java
+++ b/src/com/craftinginterpreters/lox/Interpreter.java
@@ -89,6 +89,26 @@ class Interpreter implements Expr.Visitor<Object>, Stmt.Visitor<Void> {
         stmt.accept(this);
     }
 
+    private void executeBlock(List<Stmt> statements, Environment environment) {
+        Environment previous = this.environment;
+
+        try {
+            this.environment = environment;
+
+            for (Stmt statement : statements) {
+                execute(statement);
+            }
+        } finally {
+            this.environment = previous;
+        }
+    }
+
+    @Override
+    public Void visitBlockStmt(Stmt.Block stmt) {
+        executeBlock(stmt.statements, new Environment(environment));
+        return null;
+    }
+
     @Override
     public Void visitExpressionStmt(Stmt.Expression stmt) {
         evaluate(stmt.expression);
-- 
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