 argument plugins arguments create a context from external input which is assumed to be a string as though it came from a url element title title description description keyword default keyword for the context context callback to create the context params arg null conf null empty false default either an array of default settings or a string which is a callback or null to not use settings form params form formstate conf gets the whole form should put anything it wants to keep automatically in form settings settings form validate params form formstate settings form submit params form formstate criteria form params form formstate conf argument id gets the whole argument it should only put form widgets in form id conf may not be properly initialized so always guard against this due to arguments being changed and handlers not being updated to match submit validate criteria select returns true if the selected criteria matches the context params context conf  