(* Copyright (C) 1990, Digital Equipment Corporation.         *)
(* All rights reserved.                                       *)
(* See the file COPYRIGHT for a full description.             *)

(* Last modified on Wed Jun 13 02:48:46 1990 by muller        *)
(*      modified on Thu Apr 19 13:13:55 PDT 1990 by swart     *)
(*      modified on Fri Jan 20 15:27:49 PST 1989 by glassman  *)
(*      modified on Wed Apr 22 17:34:04 1987 by roberts       *)
(*      modified on Tue Nov 25 11:48:02 1986 by brooks        *)

INTERFACE POSPath;

IMPORT Text, Rd, POS;

PROCEDURE Root(path: TEXT) : TEXT RAISES {};
    (* Returns the root part of the path and is equivalent *)
    (* to the :r substitution in the C shell.                  *)

PROCEDURE Extension(path: TEXT) : TEXT RAISES {};
    (* Returns the extension part of the path and is       *)
    (* equivalent to the :e substitution in the C shell.       *)

PROCEDURE Head(path: TEXT) : TEXT RAISES {};
    (* Returns the head part of the path and is equivalent *)
    (* to the :h substitution in the C shell.                  *)

PROCEDURE Tail(path: TEXT) : TEXT RAISES {};
    (* Returns the tail part of the path and is equivalent *)
    (* to the :t substitution in the C shell.                  *)

PROCEDURE DefaultExtension(path, ext: TEXT) : TEXT RAISES {};
    (* Adds an extension to a path if none already         *)
    (* exists.  Alternatively, if the extension field begins   *)
    (* with a *, any old extension in the first path is    *)
    (* replaced with the given extension.                      *)

PROCEDURE ExpandTilde(path: TEXT) : TEXT RAISES {POS.Error};
    (* Expands the ~ character at the beginning of a file      *)
    (* name to be the appropriate directory path.  For ~/      *)
    (* this is taken from the HOME environment variable;       *)
    (* ~user/ is converted by looking up the users home directory. *)

TYPE
  FilePredicate = PROCEDURE(name: TEXT) : BOOLEAN RAISES {};

PROCEDURE SearchPath(
    searchPath, path: TEXT;
    pred: FilePredicate := NIL) : TEXT RAISES {POS.Error};
    (* Most clients will not specify a filepred argument       *)
    (* and will use this simply to find the first file         *)
    (* that exists along a given search path.  More            *)
    (* generally, SearchPath returns a path to the         *)
    (* first instance of path in the list of               *)
    (* directories specified by the search path for which the         *)
    (* filepred returns TRUE.  If none exist, SearchPath       *)
    (* returns NIL.                                            *)

END POSPath.