Solution to ES 96 Homework 5


Frame Hierarchy.
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The unindented word or phrase is the frame name, the indented text
is the slot name. Slot values are only shown for ako and isa slots.

Property
 Owner
 Manager

Business Property
 ako Property

Personal Property
 ako Property

Physical Object
 location

Manufactured Object
 ako Physical Object
 data of manufacture

Furniture
 ako Manufactured Object
 
Electrical Device
 ako Manufactured Object
 cord length
 power requirements

Typewriter
 ako Electrical Device
 print element
 changeable fonts

Personal Typewriter
 ako Typewriter
 ako Personal Object

Personal Typewriter 1


Table
 ako Furniture
 legs

Pedestal Table
 ako Table



When Constructed Demons
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 Typewriter power requirements { 120 VAC Two Phase}
   /* Assume in USA. */

 Pedestal Table legs { return 1; }
   /* That's what a pedestal table is. */


When Requested Demons
"""""""""""""""""""""

 Personal Property manager { return owner }
   /* Owner will not be known when constructed. */


 Typewriter changeable fonts {
    if Typewriter."print element" = "golf ball"
      or 
      Typewriter."print element" = "daisy wheel"
    then return true }

 Table legs { if undefined(legs) return 4}
   /* This would not be appropriate for a when-constructed demon since there
      are many tables with other than four legs. Only return 4 if no value
      written. */

 Typewriter print element {
  if undefined( object."print element" ) and 
     (
       object.ako="Business Property"
       and
       object."date of manufacture" < 1955 
     ) or (
       object.ako="Personal Property"
       and
       object."date of manufacture" < 1985
     )
  then return "piano key"
  
  if undefined( object."print element" ) and 
     (
       object.ako="Business Property"
       and
       object."date of manufacture" > 1955 
       and
       object."date of manufacture" < 1990 
     )
  then return "golf ball"
  
  if undefined( object."print element" ) and 
     (
       object.ako="Business Property"
       and
       object."date of manufacture" > 1990
     ) or (
       object.ako="Personal Property"
       and
       object."date of manufacture" >= 1985
     )
  then return "daisy wheel"
 }
 /* The type of print element guessed from date of manufacture. "Piano
    keys" are used on old-fashion typewriters and most (all?) mechanical
    typewriters (which aren't represented in the frame hierarchy.) "Golf
    balls" were mostly used in IBM Selectric typewriters and were rarely
    used in home typewriters. */

Rules
"""""

 if 
  PrintStock.hasCarbon
  and
  (
   Typewriter."print element" = "ink jet"
   or
   Typewriter."print element" = "thermal"
  )
  then adequate(Typewriter,PrintStock):=False
 /* A "Carbon" is sheet of material coated with pressure-sensitive ink.
    It's put between two pieces of paper to make an extra copy, the
    extra copy is called a carbon copy. Since ink jet and thermal
    print elements don't exert much pressure they can't make carbons. */


 if distance( Object.location, Outlet.location ) 
    < Object."cord length"
    then powerAvailable(Object,Outlet)

 /* The rule above can be used with a typewriter instance but uses
    slots in the "Electrical Device" and "Physical Object" superclasses. */