[Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-05 Thread Jon Fairbairn
Sterling Clover [EMAIL PROTECTED] writes: of course you could rewrite this in a while loop too although you'd have to use an assignment, but at least still not one with a silly done variable. People seem to have overlooked the bit of Algol68 I posted, so I'll repeat it While If E

Re: [Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-04 Thread Brandon S. Allbery KF8NH
On Sep 4, 2007, at 5:02 , Miguel Mitrofanov wrote: It depends on arbitrary restrictions on what constitutes an (boolean) expression, something that is anathema to functional programmers :-) Spot the language: while if E then S; F else False fi do T od It reminds me of a

[Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-04 Thread Jon Fairbairn
Brandon S. Allbery KF8NH [EMAIL PROTECTED] writes: On Sep 4, 2007, at 5:02 , Miguel Mitrofanov wrote: It depends on arbitrary restrictions on what constitutes an (boolean) expression, something that is anathema to functional programmers :-) Spot the language: while if E then S; F

Re: [Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-04 Thread Vimal
I hadn't interpreted the reminding of Knuth that way. I wouldn't count break as a goto -- what makes goto especially nasty is that the destination isn't indicated by the structure of the source; it could be just anywhere. Break is slightly more structured. Maybe you might need to take a

Re: [Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-04 Thread Tillmann Rendel
Vimal wrote: Ah, yes, it is possible in this case, but you have used an extra variable. It is okay, but our professor doesnt want to put emphasis on Computability here (or maybe I dont realize it), but the point is: Are such programming constructs really necessary in a programming language? i.e.

Re: [Haskell-cafe] Re: [Off topic] Proving an impossibility

2007-09-04 Thread Sterling Clover
You get the logic and code blowup problems that require either local variables, breaks, gotos, or continuations because you're working with tests that generate side-effects. Mixing side-effects and tests is going to generate a goto, sure, but if the code was rewritten in a functional style