In a domain and in categories referenced in a domain the notation %
represents "this domain" (or self in some programming languages). So
we commonly write for example:

with
f: (%,%) -> %

to indicate a function f which takes a pair of values in this domain
and returns a value in this same domain - whatever domain we happen
to be talking about in this context.

But what if we are interested in the domain as a functor? Suppose I
was writing an "endofunctor" domain constructor like `Set`

and I
wanted to treat constructions like `Set Set R`

, i.e. sets of sets as
something special. E.g.

aldor

--)abbrev domain MYSET MySet
#pile
#include "axiom"
MonadCat(T:SetCategory,M:SetCategory->SetCategory):Category == with
join: M M T -> M T

MySet(T:SetCategory): Join(MonadCat(T,MySet),SetAggregate(T)) with
finiteAggregate
--join: MySet MySet T -> MySet T
== add
Rep == List T
--rep(x:%):Rep == x pretend Rep
--per(x:Rep):% == x pretend %

Rep2 == List List T
rep2(x:MySet MySet T):Rep2 == x pretend Rep2
per2(x:Rep2):MySet MySet T == x pretend MySet MySet T

coerce(x:%):OutputForm ==
brace(map(coerce$T, rep x)$ListFunctions2(T,OutputForm))
((x:%) = (y:%)):Boolean == (rep(x) = rep(y))$Rep
construct(x:List T):% == per(removeDuplicates(x)$Rep)
parts(x:%):List T == rep x
join(x:MySet MySet T):MySet T ==
construct(concat(rep2 x)$List(T))$%

copy(x:%):% == per(copy(rep x)$Rep)
empty():% == per(empty()$Rep)
map(f:T->T,x:%):% == per(map(f,rep x)$Rep)
brace():% == empty()$%
brace(x:List(T)):% == construct(x)$%
set():% == empty()$%
set(x:List(T)):% == construct(x)$%

-- dummy exports as required by Aldor
_<(x:%, y:%):Boolean == true
intersect(x:%, y:%):% == empty()$%
difference(x:%, y:%):% == empty()$%
subset?(x:%, y:%):Boolean == true
union(x:%, y:%):% == empty()$%
if T has ConvertibleTo(InputForm) then
convert(x:%):InputForm == convert(rep(x))$Rep

aldor

Compiling FriCAS source code from file
/var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/8835079522190382419-25px001.as
using AXIOM-XL compiler and options
-O -Fasy -Fao -Flsp -laxiom -Mno-ALDOR_W_WillObsolete -DAxiom -Y $AXIOM/algebra -I $AXIOM/algebra
Use the system command )set compiler args to change these
options.
#1 (Warning) Could not use archive file `libaxiom.al'.
#2 (Warning) Could not use archive file `libaxiom.al'.
"/usr/local/aldor/linux/1.1.0/include/axiom.as", line 4:
import from AxiomLib;
............^
[L4 C13] #3 (Error) No meaning for identifier `AxiomLib'.

"/usr/local/aldor/linux/1.1.0/include/axiom.as", line 15:
import { true: %, false: % } from Boolean;
..................................^
[L15 C35] #4 (Error) No meaning for identifier `Boolean'.

"/usr/local/aldor/linux/1.1.0/include/axiom.as", line 17:
string: Literal -> %;
........................^.......^
[L17 C25] #5 (Error) No meaning for identifier `Literal'.
[L17 C33] #6 (Error) There are no suitable meanings for the operator `->'.

"/usr/local/aldor/linux/1.1.0/include/axiom.as", line 18:
} from String;
.......^
[L18 C8] #8 (Error) No meaning for identifier `String'.

"/var/lib/zope2.10/instance/axiom-wiki/var/LatexWiki/8835079522190382419-25px001.as", line 4:
MonadCat(T:SetCategory,M:SetCategory->SetCategory):Category == with
.........^.^........................^
[L4 C10] #12 (Error) Have determined 1 possible types for the expression.
Meaning 1: ?, ?
The context requires an expression of type Tuple(Type).
[L4 C12] #9 (Error) No meaning for identifier `SetCategory'.
[L4 C37] #10 (Error) There are no suitable meanings for the operator `->'.
[L4 C37] #13 (Fatal Error) Too many errors (use `-M emax=n' or `-M no-emax' to change the limit).

The )library system command was not called after compilation.

axiom

)sh MySet

The )show system command is used to display information about types
or partial types. For example, )show Integer will show
information about Integer .

MySet is not the name of a known type constructor. If you want to
see information about any operations named MySet , issue
)display operations MySet

axiom

)di op join

There are 2 unexposed functions called join :
[1] (JetDifferentialEquation(D1,D2),JetDifferentialEquation(D1,D2))
-> JetDifferentialEquation(D1,D2)
from JetDifferentialEquation(D1,D2)
if D1 has JBC and D2 has JBFC(D1)
[2] (SparseEchelonMatrix(D1,D2),SparseEchelonMatrix(D1,D2)) ->
SparseEchelonMatrix(D1,D2)
from SparseEchelonMatrix(D1,D2)
if D1 has ORDSET and D2 has RING

axiom

MySet(Integer) has MonadCat(Integer,MySet)

There are no library operations named MySet
Use HyperDoc Browse or issue
)what op MySet
to learn if there is any operation containing " MySet " in its
name.

Cannot find a definition or applicable library operation named MySet
with argument type(s)
Type

Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.

axiom

m1:MySet(Integer) := construct([1,2,3])$MySet(Integer)

There are no library operations named MySet
Use HyperDoc Browse or issue
)what op MySet
to learn if there is any operation containing " MySet " in its
name.

Cannot find a definition or applicable library operation named MySet
with argument type(s)
Type

Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.
m2:MySet(Integer) := construct([4,5,6])$MySet(Integer)

There are no library operations named MySet
Use HyperDoc Browse or issue
)what op MySet
to learn if there is any operation containing " MySet " in its
name.

Cannot find a definition or applicable library operation named MySet
with argument type(s)
Type

Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.
ml:=[m1,m2]

axiom

mm:MySet MySet Integer := construct([m1,m2])$MySet(MySet(Integer))

There are no library operations named MySet
Use HyperDoc Browse or issue
)what op MySet
to learn if there is any operation containing " MySet " in its
name.

Cannot find a definition or applicable library operation named MySet
with argument type(s)
Type

Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.
join mm

There are no exposed library operations named join but there are 2
unexposed operations with that name. Use HyperDoc Browse or issue
)display op join
to learn more about the available operations.

Cannot find a definition or applicable library operation named join
with argument type(s)
Variable(mm)

Perhaps you should use "@" to indicate the required return type,
or "$" to specify which version of the function you need.