Re: [Axiom-developer] "has" and "with" (was curious algebra failure)

[Gabriel Dos Reis]

On Sun, 12 Aug 2007, William Sit wrote:

| On Sun, 12 Aug 2007 20:19:47 -0500 (CDT)
|  Gabriel Dos Reis <address@hidden> wrote:
| >On Sun, 12 Aug 2007, Bill Page wrote:
| >
| > | On 8/12/07, Gabriel Dos Reis wrote:
| > | > On Sun, 12 Aug 2007, Bill Page wrote:
| > | > | ...
| > | > | It should be fine because of rule 2:
| > | > |
| > | > | 2. Anonymous types are equivalent when structurally 
| >equivalent
| > | >
| > | > The parameter S in RepeatedSquare(S) of the category
| > | >
| > | >    SetCategory with "*": (%,%) -> %
| > | >
| > | > but RepeatedSquare is being called with a domain of a 
| >named category (Monad).
| > | > Rule 2 says:
| > | >
| > | >   2. Anonymous types are equivalent when stucturally 
| >equivalent
| > | >
| > | > How would it apply?
| > | >
| > | 
| > | Why do you think:
| > | 
| > |      import RepeatedSquaring(%)
| > | 
| > | is referring to a named category?
| >
| >I'm not saying that.  
| >I'm saying that the parameter S of the default package Monad& -- generated
| >for
| >the default implementation of the category Monad -- is of the named category
| >Monad.  It is that parameter S which is  being used to instantiate
| >RepeatedSquaring.  However, RepeatedSquaring expects its (domain) argument to
| >be of the unnamed category 
| >    SetCategory with "*": (%,%) -> %
| >
| >-- Gaby
| 
| Isn't the problem whether 'Monad has SetCategory with "*":(%,%)->%' ?

If the question is formulated in terms of "has", then I think the answer
is unambiguously "yes".

But, is that the way the compiler is intended or does the matching of
actual arguments with formal parameters?

It seems to me that the compiler asks the question in terms of coercible,
instead of "has".

-- Gaby