Re: [Axiom-developer] Re: SPAD and Aldor again

[Martin Rubey]

Gabriel Dos Reis <address@hidden> writes:

> Martin Rubey <address@hidden> writes:
> 
> | Gabriel Dos Reis <address@hidden> writes:
> | 
> | > | What are "algebraic types"?
> | > 
> | > Ralf and you have been doing it in your project, I think.  Basically,
> | > an algebraic type is any data type on can construct with sum and
> | > products.  Examples,
> | > 
> | >     BinaryTree t = Nil | Node t (BinaryTree t) (BinaryTree t)
> | > 
> | > 
> | > Data of algebraic type are constructed with the constructors, and they
> | > are deconstructed through pattern matching. 
> | 
> | Well, in fact I need more than that, namely mutually dependent recursively
> | defined types.
> 
> Recursive algebraic types is a redundancy :-)

But I didn't say "algebraic"! I want it for any functions F, G:
> 
>    A = F(A,B)
>    B = G(A,B)
> 
> goes without saying.

So, in what sense is "algebraic" not covered by the above?

Martin