code: function (list) {
              var comps = list.split(rlist),
              i = 0, l = comps.length,
              comp;
  
              //loop over the list of components and add if needed
              for (; i < l; ++i) {
                  comp = comps[i];
                  if (!this.has(comp)) this.addComponent(comp);
              }
  
              return this;
          }
docs: @
  #.requires
  @comp Crafty Core
  @sign public this .requires(String componentList)
  @param componentList - List of components that must be added
  
  Makes sure the entity has the components listed. If the entity does not
  have the component, it will add it.
  
  @see .addComponent