Edit detail for SandBoxNonZeroInteger revision 2 of 4

Algebra

SandBoxNonZeroInteger? is an attempt to define the domain of Integers without 0 as a SubDomain?.

(1) -> <spad>

)abbrev domain NZINT NonZeroInteger
NonZeroInteger: Join(OrderedAbelianSemiGroup, Monoid, CommutativeStar
                     --,CoercibleTo(Integer)
                    ) with
            gcd: (%,%) -> %
              ++ gcd(a,b) computes the greatest common divisor of two
              ++ positive integers \spad{a} and b.
            _-: % -> %
            --retract:Integer->%
            --retractIfCan:Integer->Union(%,"failed")
            --retract:NonNegativeInteger->%
            --retractIfCan:NonNegativeInteger->Union(%,"failed")
            --convert:NonNegativeInteger->%
 == SubDomain(Integer,#1 ~= 0) add
     Rep == Integer
     x:%
     y:%
     z:Integer
     nz:NonNegativeInteger
     -x == (-(x pretend Integer)) pretend %
     x+y ==
      (z:=(x pretend Integer)+(y pretend Integer)) = 0 => error "zero"
      z pretend %

     --coerce(x):Integer == x pretend Integer
     --retract(z)== z pretend %
     --convert(nz):% == retract(nz)
     --retractIfCan(z) ==
     --  zero?(z) => "failed"
     --  retract(z)
     --retract(nz)== nz pretend %
     --retractIfCan(nz) ==
     --  zero?(nz) => "failed"
     --  retract(nz)</spad>

Compiling FriCAS source code from file 
      /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/3042217120178961765-25px001.spad
      using system compiler.
   NZINT abbreviates domain NonZeroInteger 
------------------------------------------------------------------------
   initializing NRLIB NZINT for NonZeroInteger 
   compiling into NRLIB NZINT 
************* USER ERROR **********
available signatures for Rep: 
    NONE
NEED Rep: () -> ?
****** comp fails at level 1 with expression: ******
((DEF (|Rep|) (NIL) (|Integer|)))
****** level 1  ******
x:= (DEF (Rep) (NIL) (Integer))
m:= $EmptyMode
f:=
((((|#1| #) (* #) (+ #) (- #) ...)))

   >> Apparent user error:
   unspecified error

Built-in

There are at least two places where critical knowledge of sub-domains is built into FriCAS?.

In src/interp/i-util.boot we must extend the 'subDomainList':

isSubDomain(d1,d2) ==
  -- d1 and d2 are different domains
  --subDomainList := '(Integer NonNegativeInteger PositiveInteger)
  subDomainList := '(Integer NonZeroInteger NonNegativeInteger PositiveInteger)
  ATOM d1 or ATOM d2 => nil
  l := MEMQ(CAR d2, subDomainList) =>
    MEMQ(CAR d1, CDR l)
  nil

 
   The file 
      /var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/1905831235319360423-25px002.boot
      is needed but does not exist.

In src/interp/daase.lisp we need to make sure NonZeroInteger is known to have a 'superdomain':

(defun getdatabase (constructor key)
 (declare (special $spadroot) (special *miss*))
 (when (eq *miss* t) (format t "getdatabase call: ~20a ~a~%" constructor key))
 (let (data table stream ignore struct)
  (declare (ignore ignore))
  (when (or (symbolp constructor)
          (and (eq key 'hascategory) (pairp constructor)))
  (case key
; note that abbreviation, constructorkind and cosig are heavy hitters
; thus they occur first in the list of things to check
   (abbreviation
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
      (setq data (database-abbreviation struct))))
   (constructorkind
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-constructorkind struct))))
   (cosig
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-cosig struct))))
   (operation
    (setq stream *operation-stream*)
    (setq data (gethash constructor *operation-hash*)))
   (constructormodemap
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-constructormodemap struct))))
   (constructorcategory
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-constructorcategory struct))
     (when (null data) ;domain or package then subfield of constructormodemap
      (setq data (cadar (getdatabase constructor 'constructormodemap))))))
   (operationalist
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-operationalist struct))))
   (modemaps
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-modemaps struct))))
   (hascategory
    (setq table  *hasCategory-hash*)
    (setq stream *category-stream*)
    (setq data (gethash constructor table)))
   (object
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-object struct))))
   (asharp?
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-object struct))))
   (niladic
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-niladic struct))))
   (constructor?
    (when (setq struct (get constructor 'database))
      (setq data (when (database-operationalist struct) t))))

   ;(superdomain ; only 2 superdomains in the world
   ; (case constructor
   ;  (|NonNegativeInteger|
   ;   (setq data '((|Integer|) (IF (< |#1| 0) |false| |true|))))
   ;  (|PositiveInteger|
   ;   (setq data '((|NonNegativeInteger|) (< 0 |#1|))))))
   (superdomain ; 3 superdomains in the world
    (case constructor
     (|NonNegativeInteger|
      (setq data '((|Integer|) (IF (< |#1| 0) |false| |true|))))
     (|NonZeroInteger|
      (setq data '((|Integer|) (IF (= |#1| 0) |false| |true|))))
     (|PositiveInteger|
      (setq data '((|NonZeroInteger|) (< 0 |#1|))))))

   (constructor
    (when (setq data (get constructor 'abbreviationfor))))
   (defaultdomain
    (setq data (cadr (assoc constructor *defaultdomain-list*))))
   (ancestors
    (setq stream *interp-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-ancestors struct))))
   (sourcefile
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-sourcefile struct))))
   (constructorform
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-constructorform struct))))
   (constructorargs
    (setq data (cdr (getdatabase constructor 'constructorform))))
   (attributes
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-attributes struct))))
   (predicates
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-predicates struct))))
   (documentation
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-documentation struct))))
   (parents
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-parents struct))))
   (users
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-users struct))))
   (dependents
    (setq stream *browse-stream*)
    (when (setq struct (get constructor 'database))
     (setq data (database-dependents struct))))
   (otherwise  (warn "~%(GETDATABASE ~a ~a) failed~%" constructor key)))
  (when (numberp data)                 ;fetch the real data
   (when *miss* (format t "getdatabase miss: ~20a ~a~%" constructor key))
   (file-position stream data)
   (setq data (unsqueeze (read stream)))
   (case key ; cache the result of the database read
    (operation           (setf (gethash constructor *operation-hash*) data))
    (hascategory         (setf (gethash constructor *hascategory-hash*) data))
    (constructorkind     (setf (database-constructorkind struct) data))
    (cosig               (setf (database-cosig struct) data))
    (constructormodemap  (setf (database-constructormodemap struct) data))
    (constructorcategory (setf (database-constructorcategory struct) data))
    (operationalist      (setf (database-operationalist struct) data))
    (modemaps            (setf (database-modemaps struct) data))
    (object              (setf (database-object struct) data))
    (niladic             (setf (database-niladic struct) data))
    (abbreviation        (setf (database-abbreviation struct) data))
    (constructor         (setf (database-constructor struct) data))
    (ancestors           (setf (database-ancestors struct) data))
    (constructorform     (setf (database-constructorform struct) data))
    (attributes          (setf (database-attributes struct) data))
    (predicates          (setf (database-predicates struct) data))
    (documentation       (setf (database-documentation struct) data))
    (parents             (setf (database-parents struct) data))
    (users               (setf (database-users struct) data))
    (dependents          (setf (database-dependents struct) data))
    (sourcefile          (setf (database-sourcefile struct) data))))
   (case key ; fixup the special cases
    (sourcefile
     (when (and data (string= (directory-namestring data) "")
             (string= (pathname-type data) "spad"))

      (setq data
       (concatenate 'string $spadroot "/../../src/algebra/" data))))
    (asharp?                               ; is this asharp code?
     (if (consp data)
      (setq data (cdr data))
      (setq data nil)))
    (object                                ; fix up system object pathname
     (if (consp data)
       (setq data
             (if (string= (directory-namestring (car data)) "")
                 (concatenate 'string $spadroot "/algebra/" (car data)
                                        "." *lisp-bin-filetype*)
               (car data)))
      (when (and data (string= (directory-namestring data) ""))
       (setq data (concatenate 'string $spadroot "/algebra/" data
                                          "." *lisp-bin-filetype*)))))))
  data))

   Your user access level is compiler and this command is therefore not
      available. See the )set userlevel command for more information.

isSubDomain(devaluate(NonNegativeInteger)$Lisp,devaluate(Integer)$Lisp)$Lisp

(1)

isSubDomain(devaluate(PositiveInteger)$Lisp,devaluate(Integer)$Lisp)$Lisp

(2)

isSubDomain(devaluate(NonZeroInteger)$Lisp,devaluate(Integer)$Lisp)$Lisp

   You cannot now use NonZeroInteger in the context you have it.

)show NZINT

   You cannot now use NonZeroInteger in the context you have it.

i:NZINT := 1$NZINT

   You cannot now use NonZeroInteger in the context you have it.

j:NZINT := -1

   You cannot now use NonZeroInteger in the context you have it.

j:NZINT:=-i

   You cannot now use NonZeroInteger in the context you have it.

i-j

(3)

retractIfCan(0)$NZINT

   You cannot now use NonZeroInteger in the context you have it.