Theory loader primitives.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/Thy/thy_load.ML	Sat Jan 30 10:42:40 1999 +0100
@@ -0,0 +1,93 @@
+(*  Title:      Pure/Thy/thy_load.ML
+    ID:         $Id$
+    Author:     Markus Wenzel, TU Muenchen
+
+Theory loader primitives.
+*)
+
+signature BASIC_THY_LOAD =
+sig
+  val show_path: unit -> string list
+  val add_path: string -> unit
+  val del_path: string -> unit
+end;
+
+signature THY_LOAD =
+sig
+  include BASIC_THY_LOAD
+  val thy_ext: string
+  val find_file: Path.T -> (Path.T * File.info) option
+  val check_file: Path.T -> File.info option
+  val load_file: Path.T -> File.info
+  val check_thy: string -> File.info
+  val deps_thy: string -> File.info * (string list * Path.T list)
+  val load_thy: string -> File.info * theory
+end;
+
+signature PRIVATE_THY_LOAD =
+sig
+  include THY_LOAD
+  val deps_thy_fn: (Path.T -> string list * Path.T list) ref
+  val load_thy_fn: (Path.T -> theory) ref
+end;
+
+structure ThyLoad: PRIVATE_THY_LOAD =
+struct
+
+
+(* load path *)
+
+val load_path = ref [Path.current];
+fun change_path f = load_path := f (! load_path);
+
+fun show_path () = map Path.pack (! load_path);
+fun add_path s = change_path (fn path => path @ [Path.unpack s]);
+fun del_path s = change_path (filter_out (equal (Path.unpack s)));
+
+
+(* find / check file *)
+
+fun find_file file_src =
+  let
+    val file = Path.expand file_src;
+    fun find dir =
+      let val full_path = Path.append dir file
+      in apsome (pair full_path) (File.info full_path) end;
+  in get_first find (if Path.is_basic file then ! load_path else [Path.current]) end;
+
+
+(* process ML files *)
+
+val check_file = apsome #2 o find_file;
+
+fun load_file raw_path =
+  (case find_file raw_path of
+    Some (path, info) => (Use.use_path path; info)
+  | None => error ("Could not find ML file " ^ quote (Path.pack raw_path)));
+
+
+(* process theory files *)
+
+val thy_ext = "thy";
+
+fun process_thy f name =
+  let val path = Path.ext thy_ext (Path.basic name) in
+    (case find_file path of
+      Some (path, info) => (info, f path)
+    | None => error ("Could not find theory file " ^ quote (Path.pack path)))
+  end;
+
+(*hooks for theory syntax dependent operations*)
+fun undefined _ = raise Match;
+val deps_thy_fn = ref (undefined: Path.T -> string list * Path.T list);
+val load_thy_fn = ref (undefined: Path.T -> theory);
+
+val check_thy = #1 o process_thy (K ());
+val deps_thy = process_thy (fn path => ! deps_thy_fn path);
+val load_thy = process_thy (fn path => ! load_thy_fn path);
+
+
+end;
+
+structure BasicThyLoad: BASIC_THY_LOAD = ThyLoad;
+open BasicThyLoad;