Chapter 8: Add variable declarations

1 files changed, 20 insertions, 0 deletions

diff --git a/src/com/craftinginterpreters/lox/Environment.java b/src/com/craftinginterpreters/lox/Environment.java
new file mode 100644
index 0000000..634659b
--- /dev/null
+++ b/src/com/craftinginterpreters/lox/Environment.java
@@ -0,0 +1,20 @@
+package com.craftinginterpreters.lox;
+
+import java.util.HashMap;
+import java.util.Map;
+
+class Environment {
+    private final Map<String, Object> values = new HashMap<>();
+
+    Object get(Token name) {
+        if (values.containsKey(name.lexeme)) {
+            return values.get(name.lexeme);
+        }
+
+        throw new RuntimeError(name, "Undefined variable '" + name.lexeme + "'.");
+    }
+
+    void define(String name, Object value) {
+        values.put(name, value);
+    }
+}