Priority Search Queues implemented using Ralf Hinze's priority search pennants, see R. Hinze, A Simple Implementation Technique for Priority Search Queues.
Priority Search Queues (PSQ) are sorted maps that recognize an independent ordering on their entries' values – in this context known as priorities – in addition to the ordering on keys. It's mean, PSQ are the data type of choice when an efficient access to the smallest element of a varying collection of elements is required. It's common used by application such as discrete event simulation and job scheduling.
Currently this library implements PSQ which uses the Ord k instance for ordering their elements.