[rescue] Sick Dreamcast hacker

[Koyote]

> I haven't used the hp41 or hp48.  The friend that had an HP (model
> number unknown, but it was relatively new looking) said it was a stack
> machine with a vaguely forth like postfix operating environment.  So I
> take it from your comments that HP41s and 48s are different?

Yep- very.  The hp41 and 42 (which is software compatible) is (in many eyes, I tend to agree) the high point of evolution of "keystroke programming". I'd highly recommend finding a 20s -or if you are lucky enough to have one left in a store in lancaster- a 32sii to play with. www.rskey.org buying guide has some good explanations on this programming model, too.

> 
> Well, I probably should use an HP sometime.  I've only used TIs and
> Casios, and my comments are based on what I wish for instead.

You should *definitely* try an hp48 of some type. a 48sx is fine if you can find one with manuals under $60, otherwise just grab a cheap 48g on ebay. there's a flood of them right now.


>  
> > 2: I'm not sure about mixing prefix and postfix. I'd prefer to keep
> > posfix as it translates to actual manual entries in the calculator
> > better,IMO. 
> 
> Wait, didn't you say that HPs are using lisp?  Most people when you
> say lisp like language think s-exps with prefix notation.  Otherwise it
> is just some functional language.  The s-exps are probably the more
> important of the two, which you said nothing about.

HP 28/48/49 series calculators use lisp, yes. RPL (reverse polish lisp) is the built in list interpreter :)

It's not a *requirement* to use prefix mode to be a lisp.

It's hard to explain code line by line, but 

<< while E <<koyote>> >> 

is a valid program in RPL  (<< >> is used instead of () for various reasons)

where <<koyote>> would call a list of expressions stored in the object named koyote.

And yeah, it's postfix, object oriented, highly structured lisp. Odd, eh?

or:

(+ 3 4) EVAL
is equivalent to 
<<3 4 +>> RUN

etc.


-C



> 
> -- 
> Joshua D. Boyd
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