The SML programming language is a modern descendant of the ML programming language used in the LCF theorem-proving project. It is unique among widely used languages in that it has a formal specification, given as an operational semantics in The definition of Standard ML (Revised), by Milner, Tofte, Harper and MacQueen (ISBN 0262631814).


Some SML implementations include:

All of the implementations above are open-source and freely available. There are no commercial SML implementations.