gistfile1.txt

It's hard to answer these in a tweet :)

You can't pass arguments to computed properties unless you are creating custom setters, but that's a whole different topic!

What you probably want to do here is use an itemController for each row you are displaying (with the button.)

{{#each thing in things itemController="thing"}}
  <button {{bindAttr disabled=thing.disabled}}>button</button>
{{/each}}

// Here I am assuming you have a property, currentRange in the IndexController. The thing
// controller compares the `range` of the 'thing' with the `currentRange` of the index controller.

App.ThingController = Ember.ObjectController.extend({
  needs: ['index'],

  currentRange: Em.computed.alias('controllers.index.currentRange'),

  disabled: function() {
    return (this.get('range') === this.get('currentRange'));
  }.property('range', 'currentRange')
});