DEFINITION MODULE FileNames;

	(********************************************************)
	(*							*)
	(*		File name parsing			*)
	(*							*)
	(*  Programmer:		P. Moylan			*)
	(*  Last edited:	19 January 1993			*)
	(*  Status:		Just started			*)
	(*							*)
	(*	This module, which is part of the file system	*)
	(*	and is not intended for end-user use, looks	*)
	(*	after translating file name strings into a	*)
	(*	more convenient internal form.			*)
	(*							*)
	(********************************************************)

FROM Windows IMPORT
    (* type *)	Window;

FROM Devices IMPORT
    (* type *)	Device;

(************************************************************************)

TYPE

    (* File names (and directory names) are at most eight characters	*)
    (* long.  This archaic restriction is regretted, but we have no	*)
    (* choice if we want to remain compatible with the MS-DOS directory	*)
    (* formats.  Actually, longer names are accepted (see procedure	*)
    (* Scan), but all but the first eight characters are skipped.	*)
    (* FileNameExtension refers to the three characters which may	*)
    (* appear after a period in the complete file name.			*)

    EightChar = ARRAY [0..7] OF CHAR;		(* not exported *)
    FileNameString = EightChar;
    FileNameExtension = ARRAY [0..2] OF CHAR;
    FileName =	RECORD
		    fname: FileNameString;
		    fext: FileNameExtension;
		END (*RECORD*);

    (* The NameList form of a file name is a linked list where the	*)
    (* first entry gives the device name, following entries give the	*)
    (* directory names in order, and the last entry is the name of the	*)
    (* file within its own directory.					*)

    NameList = POINTER TO NameListRecord;
    NameListRecord= RECORD
			string: FileName;
			child: NameList;
		    END (*RECORD*);

(************************************************************************)

PROCEDURE WriteFileName (w: Window;  name: FileName);

    (* For testing: writes name in window w.	*)
    (* Probably won't need to export this in final version.	*)

PROCEDURE Parse (name: ARRAY OF CHAR;  VAR (*OUT*) device: Device;
		VAR (*OUT*) unit: CARDINAL;  VAR (*OUT*) result: NameList;
		VAR (*OUT*) StartAtRoot: BOOLEAN);

    (* Translates a text string "name" into NameList form.  If the	*)
    (* string includes a device specification this is returned as	*)
    (* (device, unit); otherwise we return with device = NullDevice.	*)
    (* Output parameter StartAtRoot is TRUE iff the filename string	*)
    (* started with a '\'.						*)

PROCEDURE DiscardNameList (VAR (*INOUT*) path: NameList);

    (* Disposes of the storage occupied by a NameList.  Returns NIL.	*)

END FileNames.