M. Edward (Ed) Borasky wrote:
>> I don't much like combining postfix notation with right-to-left
>> evaluation.  I tend to think that the notation should "precede" the
>> operands in the direction in which operations are evaluated.  Of course,
>> that's more a matter of familiarity and comfort for me than any kind of
>> objective criteria (other than consistency with traditional function
>> notation), but it's how I feel.
>>
>> In other words, if the operator notation is going to be placed to the
>> right of the operands, I'd prefer operands be evaluated right-to-left.
>>
>> Of course, I don't think *anyone* would like the way that would look, so
>> that pretty much breaks down to preferring prefix notation over postfix
>> notation.
>>     
>
> A little history:
>
> 1. Polish notation was originally prefix. It was invented by the
> Polish logician Lukaciewicz because it removed parentheses, and was
> called "Polish" notation because people had trouble spelling and
> pronouncing his name. And yes, I looked it up to get it right. :)
>
> 2. That was pretty much that until computers and programming languages
> came on the scene. But in the olden days, when every electron was
> precious and compactness and efficiency were of the utmost import, it
> turned out that *reverse* Polish notation was *slightly* more
> efficient. If you look at a parser for algebraic expressions and the
> resulting run-time execution engine, you'll see that.
>
> 3. Lisp used prefix notation because McCarthy was a disciple of Church
> and Church used it. Forth used reverse Polish notation because Chuck
> Moore had taken apart the Burroughs compilers and stack architecture
> and determined that it was the way to go for maximum compactness and
> efficiency.
>
> But the efficiency differences really are negligible these days, and
> Lisp / Scheme are much more popular than Forth. Incidentally, the RPL
> stands for "Reverse Polish Lisp".
>   
Very interesting Ed. Thanks for the contribution. ~t

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