Re: comparison operators and %pi

"Sumant S.R. Oemrawsingh" <[email protected]> writes:

> I just find this very strange:
> (1) -> %e
> 
>    (1)  %e
>                                                      Type: Expression Integer
> (2) -> %pi
> 
>    (2)  %pi
>                                                                      Type: Pi
> 
> Why is %e of type Expression Integer, while %pi is of type Pi? Is there some
> deeper reason why Pi is its own type?

For some reasons, the original developers of axiom found %pi more important
than %e.  For elements of Expression Integer there is no direct conversion to
Float, so they created an own domain HackPi, which contains only %pi and the
necessary conversion functions.  The didn't want to do the same thing with %e
though:

(2) -> %e::Float
  
   Cannot convert from type Expression Integer to Float for value
   %e


In my opinion, we should have a domain for "general" constants, i.e., like
Expression Integer but without variables, and, more generally, a domain for
expressions with a given set of variables, similar to MPOLY.  But I guess,
that's a fair bit of work.


Martin