[Axiom-math] Re: [Axiom-developer] APL, J, and Axiom documentation

[Scott Morrison]

Hi Tim,

This seems like a bizarre idea to me.  Why would you document one program with another program?  Who's to say the J program is correct?  This would mean:

1) You have to code everything twice, with the second implementation in a very obscure language.
2) You need to verify that both implementations are correct.  How can we ever guarantee that?
3) You need to learn an obscure language which is understood by almost nobody.

If I wanted to learn something about the implementation of the BesselJ function, seeing this would mean nothing to me.

> BesselJ=: 1 : '(i.0) H. (1+m.)@(_0.25&*)@*: * ^&address@hidden: % (!m.)"_'

>

>where

> J0=: 0 BesselJ

> j1=: 1 BesselJ

Since the documentation for the program contains another program, doesn't that program need to be documented too?  Also, using J baffles me.  APL is known for being very concise, but nearly unreadable.  Why would that help documentation?

I must admit, I just don't get this idea.  Can you enlighten me?

-- Scott