minimize scope for chain binding

src/bindx/BindxExt.hx

@@ -1,13 +1,12 @@
 package bindx;
-import haxe.macro.Context;
-import haxe.macro.Printer;
 
 #if macro
 
-
 import bindx.Error;
 import haxe.macro.Expr;
 import haxe.macro.Type;
+import haxe.macro.Context;
+import haxe.macro.Printer;
 
 using Lambda;
 using haxe.macro.Tools;
@@ -70,25 +69,22 @@ class BindExt {
         var fields = checkFields(expr);
         if (fields.length == 0)
             Context.fatalError("can't bind empty expression", expr.pos);
-        var flag = false;
         var i = fields.length;
         var first = null;
         while (i-- > 0) {
             var f = fields[i];
-            if (flag) f.bindable = false;
-            else if (!f.bindable) {
-                flag = true;
-                if (first == null) first = f;
-            }
+            if (first != null) f.bindable = false;
+            else if (!f.bindable && first == null) first = f;
         }
-        if (flag) {
+        if (first != null)
             Context.warning('expr in not full bindable. Can bind only "${first.e.toString()}"', expr.pos);
-        }
         
-        var chain = prepareBindChain(fields, listener, expr.pos);
+        var listenerExpr = macro listener;
+        var chain = prepareBindChain(fields, listenerExpr, expr.pos);
         
-        var res = macro
-            $b { chain.bind.concat(chain.init).concat([macro function __unbind__():Void $b { chain.unbind } ]) };
+        var res = macro (function (listener):Void->Void
+            $b { chain.bind.concat(chain.init).concat([macro return function ():Void $b { chain.unbind }]) }
+        )($listener);
         //trace(new Printer().printExpr(res));
         return res;
     }

test/ChainBindTest.hx

@@ -27,10 +27,11 @@ class ChainBindTest extends BuddySuite {
             it("BindExt.chain should bind chain changes (unset links)", {
                 b.c.c.d = val;
                 
-                var unbind = BindExt.chain(b.c.c.d, function (_, t:String) {
+                var listener = function (_, t:String) {
                     callNum++;
                     t.should.be(val);
-                });
+                };
+                var unbind = BindExt.chain(b.c.c.d, listener);
                 
                 callNum.should.be(1);
                 
@@ -88,9 +89,12 @@ class ChainBindTest extends BuddySuite {
                 b.c.c = b2.c.c;
                 callNum.should.be(3);
                 
+                Bind.notify(b.c.c.f);
+                callNum.should.be(4);
+                
                 unbind();
                 b.c.c.f("tada").d = "c";
-                callNum.should.be(3);
+                callNum.should.be(4);
             });
             
             it("BindExt.chain should bind chain changes (1 gap)", {
@@ -108,22 +112,22 @@ class ChainBindTest extends BuddySuite {
                 var b2 = new BindableChain(4);
                 b2.c.nc.c.f("tada").d = val = "c";
                 var t = b.c;
-                b.c = b2.c;
+                b.c = b2.c; // bind works
                 
                 callNum.should.be(2);
                 
                 val = t.nc.c.f("tada").d;
-                b.c = t;
+                b.c = t; // bind works
                 
                 callNum.should.be(3);
                 
                 b2.c.nc.c.f("tada").d = val = "d";
                 
-                b.c.nc.c = b2.c.nc.c;
-                callNum.should.be(3); // nc gap
+                b.c.nc.c = b2.c.nc.c; // nc gap
+                callNum.should.be(3);
                 
                 unbind();
-                b.c.nc.c.f("tada").d = "c";
+                b.c.nc.c.f("tada").d = "c"; // nc gap
                 callNum.should.be(3);
             });
             
@@ -195,11 +199,11 @@ class BindableChain implements bindx.IBindable {
     
     @:bindable
     public function f(s:String):BindableChain {
-        return c;
+        return s == "tada" ? c : null;
     }
     
     public function nf(s:String):BindableChain {
-        return nc;
+        return s == "tada" ? nc : null;
     }
     
     public function new(depth:Int) {