[update] the resolver to mark closure variables as used once discovered.

Author: vmarcella

README.md

@@ -20,8 +20,8 @@ This language is still currently experimental with many more features to come.
 * [Variables](examples/variable.ls).
 * [Conditionals](examples/conditionals.ls).
 * [Logical operators](examples/logical.ls).
-* Loops.
-* Closures.
+* [Loops](examples/loops.ls).
+* [Closures](examples/closure.ls).
 * [Recursion](examples/recursion.ls).
 * Blocks.
 * Printing.

examples/closure.ls

@@ -0,0 +1,19 @@
+// closure wraps function and keeps one variable named counter for internal
+// state.
+func Closure() {
+    var counter = 0;
+
+    func Increment() {
+        counter = counter + 1;
+        return counter;
+    }
+
+    return Increment;
+}
+
+// Gets a function from the closure back.
+var counter = Closure();
+
+// Calling counter() increments the counter.
+print counter();
+print counter();

examples/loops.ls

@@ -0,0 +1,12 @@
+var x = 0;
+
+// your typical while loop.
+while (x < 10) {
+    print x;
+    x = x + 1;
+}
+
+// Your typical for loop that does the same thing as the while.
+for (var y = 0; y < 10; y = y + 1) {
+    print y;
+}

src/Lamscript/parsing/Resolver.cpp

@@ -330,6 +330,7 @@ void Resolver::ResolveLocalVariable(
   for (int pos = scope_stack_.size() - 1; pos >= 0; pos--) {
     if (scope_stack_[pos].contains(variable_name.Lexeme)) {
       interpreter_->Resolve(expression, scope_stack_.size() - 1 - pos);
+      scope_stack_[pos][variable_name.Lexeme].Used = true;
       return;
     }
   }