HaMLet-S and Successor ML

Andreas Rossberg has updated HaMLet, a reference implementation of SML in SML, to support many of the suggestions for Successor ML (sML). The nice thing about implementing a PL in a high level PL (especially a metacircular implementation) is that it makes it easier to try out new language features.

HaMLet-S is a spin-off devoted to Successor ML (www.successor-ml.org). It incorporates a number of preliminary proposals and is a testbed and sort of a personal vision of where SML could go. Version 1.3/S4 features the following:
  • Extensible records.
  • More expressive pattern matching.
  • Views (a la Wadler and Okasaki).
  • Higher-order modules and nested signatures.
  • Local and first-class modules.
  • Miscellaneous fixes to known issues with SML.
For the intrepid who want just a quick REPL to tinker with, #sml on the freenode irc has the smlbot set to use HaMLet-S.