Re: [Axiom-developer] Curiosities with Axiom mathematical structures

[Ralf Hemmecke]

Hi Francois,

if you insist on using SPAD for new code I cannot help.

On 03/01/2006 09:56 AM, Francois Maltey wrote:
> Hello, 
>
> It seems I can define binary operator with the underscore _ 
> in any *.spad file.

In Aldor you don't need the underscore. An underscore is only needed if 
you want to write a function "mod_*" because if you write "mod*" that 
would mean "mod" "*" (two tokens).

> Are the name of the operator are fixed in the compiler or not ?

They are fixed Aldor. You find a list of them in the Aldor User Guide 
Section 4.7.1. (http://www.aldor.org/docs/HTML/index.html)

> Can I define my own new operator azerty or not ?

If you mean "binary infix operator" then the answer is NO.

>   for computing 1 azerty 2 azerty 3 azerty 4 without problem.

> Can I define my own factorial with ! or not ?

I haven't seen postfix operators in Aldor.

>   the ! operator is a postfix one.     3!
>   but the - operator is a prefix one. -3

> Why are there 2 underscore in _/_\ in boolean.spad ?

Simple. SPAD does not consider \ and / to be letters that can be used in 
an identifier. By escaping them with an _ you basically turn them into 
"nice" letters.



> Logic: Category == BasicType with
>        _~:        % -> %
>         ++ ~(x) returns the logical complement of x.
>        _/_\:       (%, %) -> %
>         ++ \spadignore { /\ }returns the logical `meet', e.g. `and'.
>        _\_/:       (%, %) -> %
>         ++ \spadignore{ \/ } returns the logical `join', e.g. `or'.
>
> Can I do this in a *.input file for the interpreter ?

No idea.

> Can I fix a priority for each operator ?

No. That is fixed in Aldor.

Ralf