Re: [Axiom-developer] RE: FW: data structure vs. mathematical structure

[Martin Rubey]

"Page, Bill" <address@hidden> writes:
> [...] It defines a List as the least fixed
> point of
>
>       X |-> 1 + T x X
>
By the way, in aldor-combinat (or axiom-combinat, if you like), you can define
an equivalent to "List L" as


macro {
        I == EmptySetSpecies;
        X == SingletonSpecies;
        + == Plus;
        * == Times;
}

List(L: LabelType): CombinatorialSpecies L == (I + X*List)(L) add;

That's all. All the logic is hidden in CombinatorialSpecies, Plus and
Times. Well, not quite, but to see what's missing (and how to easily add it)
you'll have to read the docs.

It's Ralf who made this possible, I'd like to add.

Martin