Re: Spad and inductive types

Martin Rubey <[email protected]> writes:

| Here you go.  But I doubt somehow that Gaby had this in mind, since this is
| quite usual stuff in Axiom (grep "Rep.*Union")


Thanks, Martin.

I did not say I did not know how to write it.  I said "I don't have a
good way" :-).  Everything I've tried to come up (including proposed
solutions here)  with looked a hack to me.  Part of the reasons is

  --     MkAdd ==> Record(lAdd:%,rAdd:%)
  --     MkMul ==> Record(lMul:%,rMul:%)

if union are used whose fields are directly records, then the fields
of the record must themselves have different name.  In the Boot or
Haskell case, only the data constructor name need to be different.
I fully understand Spad is not Haskell, neither Boot, but I'm looking
for a solution where only the toplevel data constructors needs to be
different.  I have more to say later.

-- Gaby