INTERFACE M3FindFile;

(***************************************************************************)
(*                      Copyright (C) Olivetti 1989                        *)
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(***************************************************************************)

IMPORT Text;
IMPORT M3Extension;


EXCEPTION
  Failed;

TYPE
  T = OBJECT
  METHODS
    exts(): M3Extension.TSet;
    find(name: Text.T; ext: M3Extension.T): Text.T RAISES {Failed};
  END;

(* objects of this type are used to find a file name given a module or
interface name and an extension.
  The 'exts' method returns the set of extensions for which the file finder
provides this lookup service. Trying to look up a file with an extension not
in the set returned by 'exts' will typically cause a checked runtime error.
  The 'find' method does the work; it constructs the name of the file
corresponding to 'name' and 'ext' and returns it. If there is no such file it
raises 'Failed'. For example a simple file 'find' method might just use
'M3Extension.Extend' to construct a file name and then check if the name
corresponds to an existing file. More complex 'find' methods might look for
the corresponding file in some list of locations.
  Note that on some systems a file may exist but it is impossible to tell that
it exists because it is totally inaccessible. If the file corresponding to
'name' and 'ext' is totally inaccessible in this way the 'find' method will
raise 'Failed' *)

END M3FindFile.