Gaby,
I am enthusiastic about this kind of change, but as usual I have some
comments and questions ... :-)
On Sat, May 17, 2008 at 2:03 PM, Gabriel Dos Reis wrote:
>
> As of revision 573, the interpreter now accepts calling a constructor
> with a homogeneous variable length argument list, when the constructor
> is defined to take a tuple. This new capability makes it possible
> to define domains like Enumeration as ordinary OpenAxiom domains.
Good!
> For example, given
>
> )abbrev domain MYENUM MyEnum
> MyEnum(enums: Tuple Symbol): Public == Private where
> Public ==> SetCategory with
> coerce: Symbol -> %
>
> Private ==> add
> Rep == NonNegativeInteger
>
> coerce(s: Symbol): % ==
> for i in 0..(length enums - 1) repeat
> s = select(enums,i) => return per i
> userError [s, "is not a valid enumerator"]
>
> e1 = e2 ==
> rep e1 = rep e2
>
> coerce(e: %): OutputForm ==
> select(enums, rep e)::OutputForm
>
>
> I have
>
> (1) -> WeekDay := MyEnum(Mon,Tue,Wed,Thu,Fri)
>
> (1) MyEnum(Mon,Tue,Wed,Thu,Fri)
> Type: Domain
> (2) -> Mon :: WeekDay
>
> (2) Mon
> Type: MyEnum(Mon,Tue,Wed,Thu,Fri)
>
> (3) -> Sat::WeekDay
>
> >> Apparent user error:
> Sat
> is not a valid enumerator
>
Question:
1) What happens if there is more that one Tuple or another type of
argument in the argument list? E.g.
TupleDom(sym: Tuple Symbol, str:String, int: Tuple Integer):
Public == Private where
2) Can I write something like?
MyDom := TupleDom( (x,y,z,w,u), "test", (1,2,3,4,5))
or do I still need to use [x,y,z ... ] ?
3) Can I use Tuple in a similar manner when calling a function? E.g.
t(x:Tuple PI):INT == length(x)
t(1,2,3)
instead of?
t([1,2,3])
Comments:
1) Besides 'Tuple', would it also be possible to treat 'Record' and
'Union' this way? E.g.
RecDom(arg:Record(sym: Symbol, str:String, int: Integer)): Public
== Private where
if arg.sym=x and arg.str="x" or arg.int=0 then ...
MyDom := RecDom(x,"x",1)
----------
UnionDom(arg:Union(sym: Symbol, str:String, int: Integer)):
Public == Private where
if arg case sym then ...
MyDom := UnionDom("x")
----------
(1) -> f(x:Union(Integer,Float)):Union(Integer,Float) == (x case
Integer => x+1; x+1)
Function declaration f : Union(Integer,Float) -> Union(Integer,Float)
has been added to workspace.
Type: Void
(2) -> f(2.0)
Compiling function f with type Union(Integer,Float) -> Union(Integer,Float)
(2) 3.0
Type: Union(Float,...)
(3) -> f(2)
(3) 3.0
Type: Union(Float,...)
(4) -> f(-1::Union(Integer,Float))
(4) 0.0
Type: Union(Float,...)
---------
Regards,
Bill Page.
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