>               I really do not know much about Forth, but I remember that 
> its design strongly is based on stacks, which leads to a syntax which is 
> rather strange compared to other programming language: the "Inverted 
> Polish Notation". Obviously, (one of) the mathematician(s) who invented 
> Forth hailed from Poland...

It's prefix notation that is called Polish notation, and is named for 
the Polish mathemetician Jan Lukasiewicz.  In this notation instead of 
writing 2 + 3 you write + 2 3.  So postfix (2 3 +) is called reverse 
Polish.  This is what HP calculators and the Forth language use.  (I 
still use my HP41CX frequently.)  The Forth language was developed by an 
American named Charles Moore.  It was originally developed to control 
astronomical equipment.

This info is partly from memory and partly from a couple of quick Google 
searches for the names...    :-)

Incidentally, Forth is a fascinating programming language -- I used to 
dabble with it some, but never learned it very well.    :-(

      -=- Larry -=-

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> >Hehe... the whole sub-thread wouldn't have started if Charles had used
> >an upper case "p" for his "polish"...


Gotta be careful around this group huh? :D

Charles

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> All I can say is "why not." Calculators cost money but you can make one for
> free.  Actually I have my old HP48 but wanted to do this anyway.

I want a TI-81, but anyway...

> Where I got stuck before (this is an old project which I recently came back
> to) was that I needed to be able to have a whole arbitrary expression as a
> string that I could display as well as evaluating it to a float that I
> could plot.  val() of course can convert a string literal to a float, but
> val("2+2") returns the number 2.

Yes... AFAIK, POV-Ray doesn't have anything to evaluate a string as a 
command. (Except your current method, obviously.)

> Any better ideas?

GNUplot will plot most functions you can think of quickly and easily. 
(Also has a bunch of additional features - it handles complex numbers, 
can do logarithmic axies, can do half a dozen different types of 
statistical plots, will plot data from a file, etc etc etc...)

;-)

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Among other things, Rick Measham <rickm*at%isite.net.au> saw fit to write:

>> Hehe I like reverse polish on my HP
> 
> Is reverse polish done with something like this??
> 
> finish{
> phong -1
> }

It's more like:

-1
phong
finish

(or should I say Finnish?) ;-)

-- 
light_source{9+9*x,1}camera{orthographic look_at(1-y)/4angle 30location
9/4-z*4}light_source{-9*z,1}union{box{.9-z.1+x clipped_by{plane{2+y-4*x
0}}}box{z-y-.1.1+z}box{-.1.1+x}box{.1z-.1}pigment{rgb<.8.2,1>}}//Jellby

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Orchid XP v2 wrote:
> 
> I want a TI-81, but anyway...
> 

OT, but has anyone else but me ever thought that TI-85 (and many others)
could be mentioned even as PDA?

-- 
Eero "Aero" Ahonen
   http://www.zbxt.net
      aer### [at] removethiszbxtnetinvalid

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"Eero Ahonen" <aer### [at] removethiszbxtnetinvalid> wrote in message
news:43a47a7f$1@news.povray.org
> Orchid XP v2 wrote:
>>
>> I want a TI-81, but anyway...
>>
>
> OT, but has anyone else but me ever thought that TI-85 (and many
> others) could be mentioned even as PDA?

Our school got a special deal on TI-86s (about half price IIRC).  As you can 
imagine, within a few weeks everyone was playing super mario and tetris 
during lessons :-)

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> Our school got a special deal on TI-86s (about half price IIRC).  As you can 
> imagine, within a few weeks everyone was playing super mario and tetris 
> during lessons :-)

LMAO!

Yeah, that sounds about right...


At my school, the staff didn't really "understand" new-fangled things 
like electrisity, etc. After many years, we eventually got a few 186 
PCs. Within about 4 weeks somebody had figured out that the teacher's 
password was "teacher", and had installed the (then very new) Doom on 
the PC. (Inside a folder called ".", IIRC. This made running the program 
rather difficult! But that was the idea... tho personally I don't think 
they need have bothered.)


Seriously though - I currently have a graphing calculator which is 
"programmable". That is, you can make the menus appear in a pre-scripted 
order, and fill in some of the fields with hard-coded values. Or even 
the contents of variables (of which there are 26 available). What you 
*can't* do is conditional branching, looping, subroutines, user input...

The calculator has a feature to graph a table, and to tabulate a 
function, and to tabulate a recursive function. But if the recursion 
isn't one of the 3 formats the calculator supports... you *cannot* 
compute it automatically. You must do it by hand. Oh, and you can't 
build a table by hand. In short, without using lots of paper, it is 
*impossible* to graph anything except an explicit function or a few 
specific kinds of recursion. Very programmable...

I'm hoping that a TI-81 wouldn't have such limitations.

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