Resolve reports variable redeclaration errors

Hamled · Oct 9, 2019 · 8466bd2 · 8466bd2
1 parent 1f30d2f
commit 8466bd2
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diff --git a/jlox/src/dev/hamled/craftinginterpreters/lox/Lox.java b/jlox/src/dev/hamled/craftinginterpreters/lox/Lox.java
@@ -64,6 +64,9 @@ private static void run(String source) {
         Resolver resolver = new Resolver(interpeter);
         resolver.resolve(statements);
 
+        // Stop if there was a resolution error.
+        if(hadError) return;
+
         interpeter.interpret(statements);
     }
 

diff --git a/jlox/src/dev/hamled/craftinginterpreters/lox/Resolver.java b/jlox/src/dev/hamled/craftinginterpreters/lox/Resolver.java
@@ -175,6 +175,10 @@ private void declare(Token name) {
         if(scopes.isEmpty()) return;
 
         Map<String, Boolean> scope = scopes.peek();
+        if(scope.containsKey(name.lexeme)) {
+            Lox.error(name,
+                    "Variable with this name already declared in this scope.");
+        }
         scope.put(name.lexeme, false);
     }