src/Pure/ProofGeneral/pgip.ML

authentic syntax for classes and type constructors;
read/intern formal entities just after raw parsing, extern just before final pretty printing;
discontinued _class token translation;
moved Local_Syntax.extern_term to Syntax/printer.ML;
misc tuning;

(*  Title:      Pure/ProofGeneral/pgip.ML
    Author:     David Aspinall

Prover-side PGIP abstraction.  
Not too closely tied to Isabelle, to help with reuse/porting.
*)

signature PGIP =
sig
    include PGIPTYPES
    include PGIPMARKUP
    include PGIPINPUT
    include PGIPOUTPUT
end

structure Pgip : PGIP = 
struct
   open PgipTypes
   open PgipMarkup
   open PgipInput
   open PgipOutput
end