From 57e87978ef416ce2898a65a9b67e37be91263e67 Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Wed, 25 Nov 2020 22:06:42 -0800
Subject: Chapter 8: Add assignment

---
 src/com/craftinginterpreters/lox/Parser.java | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

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

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();
 
-- 
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