# Polish notation [was: writing Chinese dialects]

From: Guy Steele (Guy.Steele@sun.com)
Date: Tue Feb 06 2007 - 12:18:52 CST

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After its inventor, the Polish logician Jan Łukasiewicz.
(Properly speaking, "Polish" should be capitalized in this
usage.) See http://en.wikipedia.org/wiki/Polish_notation .

The particular notation used by Łukasiewicz was embodied
in a dice game called "Wff'n'Proof", which I remember being
advertized in _Scientific_American_ a good 40 years ago
and which is still available at http://wffnproof.com .

The parenthesized notation used in the Lisp programming
language is sometimes called "Cambridge Polish notation"
(or simply "Cambridge Polish") after Cambridge, Massachusetts,
home of MIT, where Lisp was invented by John McCarthy. See
http://www.cs.hmc.edu/claremont/keller/webBook/ch08/sec11.html .

--Guy Steele

On Feb 6, 2007, at 10:42 AM, vunzndi@vfemail.net wrote:

>
> Ah, why is it called polish order?
>
> Quoting James Cloos <cloos@jhcloos.com>:
>
>>>>>>> "vunzndi" == vunzndi <vunzndi@vfemail.net> writes:
>>
>> vunzndi> Standard ids addresses this by using reverse polish order,
>> vunzndi> ... , in this case (a+b)/c becomes /+abc, whereas a+b/c
>> vunzndi> becomes +ab/c .
>>
>> Actually, that is polish order, not reverse polish. Polish order is
>> as seen in lisp: << (+ 1 4) >> returns 5. Reverse Polish order
>> is as
>> seen in stack-based languages like forth: << 1 4 + >> returns 5.
>>
>> So, infix (a+b)/c is ab+c/ and infix a+b/c is abc/+ in Reverse
>> Polish.
>>
>> -JimC
>> --
>> James Cloos <cloos@jhcloos.com> OpenPGP: 1024D/ED7DAEA6
>>
>
>
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