More on Patchable Systems

[Mike McMahon <MMcM at MIT-AI>]

    Date: 17 December 1981 16:16-EST
    From: Gerald R. Barber <JerryB at MIT-AI>
    In System 78.18, ZMail 38.2, Local-File 30.3, Experimental MEGA 2.0, microcode 836, on Lisp Machine Eighteen:
    Is it really true that two patchable systems and their associated patch
    directories cannot live on the same filecomputer directory as shown
    below.  This seems unduly restrictive.  Isn't there a way to force the
    use of the patch file naming convention that is used when the patch
    directory is different from the system default pathname.
Yes, the atom "PATCH" is under system control, as the second argument to the :PATCHABLE
macro.  This is a recent feature, so i could not guarantee that it is documented in the
manual.  So, do

    (DEFSYSTEM foo1
      (:PATHNAME-DEFAULT "ai:jerryb;")
      (:PATCHABLE)
      (:PACKAGE "TV")
      (:MODULE MAIN "besc")
      (:COMPILE-LOAD MAIN))

("AI: JERRYB; PAT10 (PDIR)").  But

    (DEFSYSTEM foo2
      (:PATHNAME-DEFAULT "ai:jerryb;")
      (:PATCHABLE NIL "QATCH")
      (:PACKAGE "si")
      (:MODULE MAIN "maks")
      (:COMPILE-LOAD MAIN))

("AI: JERRYB; QAT10 (PDIR)").  Etc.  Note that on ITS the first letter
of the atom has to be unique, Q69.12 is all there's room for in six
characters.