Re: silly question: prefix vs postfix ops

MattR wrote:
> This is more of a language question than a compiler question (and
> therefore should create a religious battle :) ), but I'm wondering if
> the answer has more to do with the compiler. Anyway, why are there
> prefix operators that could just as well be postfix? Why is it !a and
> not a!, or *a and not a* ? I can understand the increment and
> decrement operators, and the & op but expressions like *a[i] would be
> a lot clearer if it were a[i]*, just read the operators from right to
> left. Is it a case of, well, it's always been done this way?


In the Lukasiewicz notation, all operators are prefix. This is used
in proof theory, for example Shoenfield, "Mathematical Logic". The
postfix notation was invented later - it is particularly easy to
implement with stacks.
      http://en.wikipedia.org/wiki/Polish_notation
      http://en.wikipedia.org/wiki/Reverse_Polish_notation


So today, it is just a notational convention. Mixing in the same
language, may cause ambiguities. This happens for example in music, when
writing chords like A#7. Here, for some reason one may like to write A#
and #7. So some disambiguation is needed if the operator order is to be
kept: parenthesizes, superscripts, or something.


      Hans Aberg

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