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Re: Fizz Buzz Zoom

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anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:
> What's a "DRY problem"?

DRY = Don't Repeat Yourself.  Basically, "this should be factored some
more".

>   Write a program that prints the numbers from 1 to 121. But for
>   multiples of three print "Fizz" instead of the number and for the
>   multiples of five print "Buzz". For numbers which are multiples of
>   both three and five print "FizzBuzz".  For numbers which are multiples
>   of seven, print "Zoom".  For numbers which are multiples of three and
>   seven, print "FizzZoom".  For numbers which are multiples of five and
>   seven, print "BuzzZoom".  For numbers which are multiples of three,
>   five and seven, print "FizzBuzzZoom".

This seems like a messy specification to me, and also an incorrect or
ambiguous one, since (e.g.) for n=15 it allows printing "Fizz Buzz
FizzBuzz".  Its size also grows exponentially in the number of divisors.
Here's another attempt:

   Write a program that prints the numbers from 1 to 120 (inclusive) in
   FBZ (Fizz-Buzz-Zoom) notation, one per line.  For a natural number n
   that is coprime to 3, 5, and 7, the FBZ notation for n is the same as
   the decimal representation of n.  For other natural numbers n, the
   FBZ notation for n is the concatenation of the F, B, and Z notations
   for n.  The F notation for natural n is the string "Fizz" if n is a
   multiple of 3, otherwise it is the empty string.  The B notation for
   natural n is the string "Buzz" if n is a multiple of 5, otherwise it
   is the empty string.  The Z notation for natural n is the string
   "Zoom" if n is a multiple of 7, otherwise it is the empty string.

That is also a messy spec, but most ways I see to clean it up involve
introducing more machinery that in other ways makes it worse.  I do
think the monoid implementation

   fbz n = fromMaybe (show n) (mconcat [f 3 "Fizz", f 5 "Buzz", f 7 "Zoom"])
     where f d s = if n`mod`d==0 then Just s else Nothing
   main = map (putStrLn . fbz) [1..120]

is the most conceptually explicit reflection of how I see the problem,
even though in actual code I like the list-based version better due to
it having fewer implementation artifacts (library dependencies etc.)

Anyway, as someone in the earlier clf thread mentioned, it's an
interview question rather than a "program from spec" problem.  In that
situation, some ambiguity can be a good thing since it lets you see the
candidate's approach to resolving it.  

There is a formal specification language called Z-notation (nothing to
do with the "Z notation" above) that some Ada projects use.  Now I'm
sort of wondering what a Z-notation spec for this problem would look
like.

> That spec naturally leads to a solution you consider "ugly".  Now
> maybe someone can write a less ugly specification, and maybe that
> naturally leads to a less ugly program.

Even with a formal spec, it's still appropriate to identify the patterns
inherent in the spec and reflect them in the code.

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Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-07 09:19 -0700
  Re: Fizz Buzz Zoom mhx@iae.nl (Marcel Hendrix) - 2012-10-07 20:33 +0200
    Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-07 11:43 -0700
      Re: Fizz Buzz Zoom mhx@iae.nl (Marcel Hendrix) - 2012-10-07 21:09 +0200
        Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-07 12:18 -0700
          Re: Fizz Buzz Zoom ouatubi@gmail.com - 2012-10-08 01:15 -0700
            Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 09:37 -0700
              Re: Fizz Buzz Zoom ouatubi@gmail.com - 2012-10-09 01:16 -0700
  Re: Fizz Buzz Zoom Doug Hoffman <glidedog@gmail.com> - 2012-10-07 14:45 -0400
    Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-07 12:28 -0700
      Re: Fizz Buzz Zoom Doug Hoffman <glidedog@gmail.com> - 2012-10-07 21:06 -0400
        Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-07 21:32 -0700
          Re: Fizz Buzz Zoom Doug Hoffman <glidedog@gmail.com> - 2012-10-08 06:06 -0400
            Re: Fizz Buzz Zoom Mark Wills <forthfreak@gmail.com> - 2012-10-08 05:24 -0700
  Re: Fizz Buzz Zoom anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-08 14:02 +0000
    Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 08:38 -0700
      Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 08:43 -0700
      Re: Fizz Buzz Zoom "A. K." <akk@nospam.org> - 2012-10-08 18:03 +0200
      Re: Fizz Buzz Zoom anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-08 16:08 +0000
        Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 09:23 -0700
          Re: Fizz Buzz Zoom anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-08 17:11 +0000
            Re: Fizz Buzz Zoom Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-08 22:12 +0200
            Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 13:16 -0700
              Re: Fizz Buzz Zoom Hannu Vuolasaho <hannu.vuolasaho@nospam.tut.fi.invalid> - 2012-10-08 21:06 +0000
                Re: Fizz Buzz Zoom "Elizabeth D. Rather" <erather@forth.com> - 2012-10-08 11:57 -1000
                Re: Fizz Buzz Zoom Mark Wills <forthfreak@gmail.com> - 2012-10-09 01:26 -0700
                Re: Fizz Buzz Zoom George Hubert <georgeahubert@yahoo.co.uk> - 2012-10-09 08:38 -0700
                Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-09 09:03 -0700
                Re: Fizz Buzz Zoom "Elizabeth D. Rather" <erather@forth.com> - 2012-10-09 08:44 -1000
              Re: Fizz Buzz Zoom anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-10 12:32 +0000
                Re: Fizz Buzz Zoom Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-10 16:59 +0200
                Re: Fizz Buzz Zoom anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-10-10 16:42 +0000
                Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-12 21:18 -0700
                Re: Fizz Buzz Zoom "Elizabeth D. Rather" <erather@forth.com> - 2012-10-12 21:06 -1000
      Re: Fizz Buzz Zoom Doug Hoffman <glidedog@gmail.com> - 2012-10-10 09:02 -0400
  Re: Fizz Buzz Zoom Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-10-08 17:50 +0100
    Re: Fizz Buzz Zoom Paul Rubin <no.email@nospam.invalid> - 2012-10-08 10:15 -0700

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