It's maybe impossible to have parenthesis for cross-product,
because they are used for functions,
Parentheses are used for grouping. You know that , (comma) in Aldor is
an operator (with a very low precedence) that forms so called
multivalues? So in
a, b := b, a
you must have parens around (a,b) and (b,a) if you mean a parallel
assignment. Otherwise it would parse as
a, (b:=b), a
but a new constructor as [|...,...|]
should be a great progress in the interface.
There is no more syntax needed.
By example caml uses [1;2;3] for lists and [|1;2;3|] for array.
And mupad allows [a,b] := L when L is a list of 2 terms.
So [a,b] := [b,a] exchanges the values of the variables a and b.
And it already works in Axiom.
(1) -> a:INT:=3
(1) 3
Type: Integer
(2) -> b:INT:=7
(2) 7
Type: Integer
(3) -> (b,a):=(a,b)
(3) 7
Type: Integer
(4) -> a
(4) 7
Type: Integer
(5) -> b
(5) 3
Type: Integer
> and [a,b,c] := [b,c,a] permutes the 3 values.
(6) -> c:INT := 1
(6) 1
Type: Integer
(7) -> (a,b,c) := (b,c,a)
(7) 7
Type: Integer
(8) -> a
(8) 3
Type: Integer
(9) -> b
(9) 1
Type: Integer
(10) -> c
(10) 7
Type: Integer
Ralf
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