Chapter 8: Add assignment

1 files changed, 9 insertions, 0 deletions

diff --git a/src/com/craftinginterpreters/lox/Environment.java b/src/com/craftinginterpreters/lox/Environment.java
index 634659b..8d8a374 100644
--- a/src/com/craftinginterpreters/lox/Environment.java
+++ b/src/com/craftinginterpreters/lox/Environment.java
@@ -14,6 +14,15 @@ class Environment {
         throw new RuntimeError(name, "Undefined variable '" + name.lexeme + "'.");
     }
 
+    void assign(Token name, Object value) {
+        if (values.containsKey(name.lexeme)) {
+            values.put(name.lexeme, value);
+            return;
+        }
+
+        throw new RuntimeError(name, "Undefined variable '" + name.lexeme + "'.");
+    }
+
     void define(String name, Object value) {
         values.put(name, value);
     }