Chapter 8: Add assignment

1 files changed, 19 insertions, 1 deletions

diff --git a/src/com/craftinginterpreters/lox/Parser.java b/src/com/craftinginterpreters/lox/Parser.java
index 9a9c0e6..9e76a54 100644
--- a/src/com/craftinginterpreters/lox/Parser.java
+++ b/src/com/craftinginterpreters/lox/Parser.java
@@ -27,7 +27,7 @@ class Parser {
     }
 
     private Expr expression() {
-        return equality();
+        return assignment();
     }
 
     private Stmt declaration() {
@@ -73,6 +73,24 @@ class Parser {
         return new Stmt.Expression(expr);
     }
 
+    private Expr assignment() {
+        Expr expr = equality();
+
+        if (match(EQUAL)) {
+            Token equals = previous();
+            Expr value = assignment();
+
+            if (expr instanceof Expr.Variable) {
+                Token name = ((Expr.Variable) expr).name;
+                return new Expr.Assign(name, value);
+            }
+
+            error(equals, "Invalid assignment target.");
+        }
+
+        return expr;
+    }
+
     private Expr equality() {
         Expr expr = comparison();