sealing-box: Add a doc comment (currently rather more hope than reality)

diff --git a/sealing-box.scad.m4 b/sealing-box.scad.m4
index 26697d182fcc64638de9bd1d6cbb2799699146d6..21d54ec9873d36887b98fc5f731b6ec3e7170d38 100644 (file)
--- a/sealing-box.scad.m4
+++ b/sealing-box.scad.m4
@@ -1,5 +1,23 @@
 // -*- C -*-
 
+// This file can be used in two ways:
+//
+// A. Rectangular boxes
+//      1. include <sealing-box.scad>
+//      2. assign() values to (xxx these should be $ variables)
+//           ts_xbox (outer dimensions)
+//           ts_ybox (outer dimension)
+//           ts_zbox (??? xxx)
+//           ts_cnrrad (outer radius of corners, leave at default normall)
+//                 xxx default should be in this file
+//      3. use the modules
+//           SealingBox_RectBox
+//           SealingBox_RectLid
+//
+// B. Complicated shapes, but harder work
+//      1. Be a .m4 file and m4_include sealing-box.scad.m4
+//      2. Maybe define your own BoxDoShapeRect xxx tbd
+
 m4_dnl Box_Part($1=transl_x,$2=transl_y, $3=rot_z,$4=mirror_xy)
 m4_dnl          $5=kind, $6=kindargs, $7=profile(profileargsargs))
 m4_define(`Box_Part',`