The MetaPRL compiler defines syntax in two modules: the Perv module, defined in the directory theories/display/perv.mli, and the Summary module, defined in theories/display/summary.mli. These modules have two different purposes: the Perv module defines terms that are commonly use to represent refiner primitives: it includes a list construction with cons and nil terms, a primitive lambda abstraction, and a sequent representation.
The Summary module provides the syntax for theories. It contains one or more term declarations for each of the syntax constructions in a MetaPRL theory module. These constructions may contain OCaml programs; the programs are defined in the file theories/ocaml/ocaml.mli.
The Nuprl_font module defines the character set used in MetaPRL for displaying terms. For more information on the character set used in MetaPRL refer to the "MetaPRL font" section of the MetaPRL User Guide