export default function(signal, scope) {
  var op = scope.addSignal(signal.name, signal.value);
  if (signal.react === false) op.react = false;
  if (signal.bind) scope.addBinding(signal.name, signal.bind);
}

@@ -1,8 +1,42 @@
+import %7Berror%7D from 'vega-util';%0A%0A
 export d
@@ -74,16 +74,291 @@
 %7B%0A  var 
+name = signal.name;%0A%0A  if (signal.outer) %7B%0A    // signal must already be defined, raise error if not%0A    if (!scope.signals%5Bname%5D) %7B%0A      error('Missing prior signal definition for %22outer%22: ' + name);%0A    %7D%0A  %7D else %7B%0A    // define a new signal in the current scope%0A    var 
 op = sco
@@ -368,21 +368,14 @@
 addS
-ignal(s
 ignal
-.
+(
 name
@@ -391,16 +391,18 @@
 value);%0A
+  
   if (si
@@ -441,16 +441,18 @@
  false;%0A
+  
   if (si
@@ -479,23 +479,16 @@
 Binding(
-signal.
 name, si
@@ -499,10 +499,14 @@
 .bind);%0A
+  %7D%0A
 %7D%0A

Add support for signal updates to outer scope.