The following features are special to this version of HOPE: irrefutable patterns, operator sections, functions of more than one argument, recursive type definitions, input, read, write, private, abstype, letrec and whererec. Other versions may not support full lazy evaluation, and may have several features not provided here.
This version also supports curried type and data constructors.
The rest of this appendix describes some experimental features of this version of the language.