From 958ba22a570594ed2ce60d24cd082ce3b8a6b89a Mon Sep 17 00:00:00 2001
From: Tom Willemse
Date: Sat, 12 Jun 2021 12:17:43 -0700
Subject: 12.7 Constructors and Initializers

---
 src/com/craftinginterpreters/lox/Resolver.java | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

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

diff --git a/src/com/craftinginterpreters/lox/Resolver.java b/src/com/craftinginterpreters/lox/Resolver.java
index 70c5970..cda0f60 100644
--- a/src/com/craftinginterpreters/lox/Resolver.java
+++ b/src/com/craftinginterpreters/lox/Resolver.java
@@ -15,12 +15,11 @@ class Resolver implements Expr.Visitor<Void>, Stmt.Visitor<Void> {
     }
 
     private enum FunctionType {
-        NONE, FUNCTION, METHOD
+        NONE, FUNCTION, INITIALIZER, METHOD
     }
 
     private enum ClassType {
-        NONE,
-        CLASS
+        NONE, CLASS
     }
 
     private ClassType currentClass = ClassType.NONE;
@@ -52,6 +51,9 @@ class Resolver implements Expr.Visitor<Void>, Stmt.Visitor<Void> {
 
         for (Stmt.Function method : stmt.methods) {
             FunctionType declaration = FunctionType.METHOD;
+            if (method.name.lexeme.equals("init")) {
+                declaration = FunctionType.INITIALIZER;
+            }
             resolveFunction(method, declaration);
         }
 
@@ -98,6 +100,9 @@ class Resolver implements Expr.Visitor<Void>, Stmt.Visitor<Void> {
         }
 
         if (stmt.value != null) {
+            if (currentFunction == FunctionType.INITIALIZER) {
+                Lox.error(stmt.keyword, "Can't return a value from an initializer.");
+            }
             resolve(stmt.value);
         }
 
@@ -173,8 +178,7 @@ class Resolver implements Expr.Visitor<Void>, Stmt.Visitor<Void> {
     @Override
     public Void visitThisExpr(Expr.This expr) {
         if (currentClass == ClassType.NONE) {
-            Lox.error(expr.keyword,
-                      "Can't use 'this' outside of a class.");
+            Lox.error(expr.keyword, "Can't use 'this' outside of a class.");
             return null;
         }
 
-- 
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