53 lines
2.3 KiB
Markdown
53 lines
2.3 KiB
Markdown
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# wheel-utils
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I wanted to write a fast, straight-forward, extensible fizzbuzz program. This is a small utility I wrote to do it. It can generate simple wheels that you can use if you have a recurring sequence (like fizzbuzz).
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## documentation
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## usage
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Put it in your site-dir. Then you should be able to:
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(use-modules (wheel-utils wheel))
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### every-n in value [n]
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(every-n-in "fizz" 3) -> '(#f #f "fizz")
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(every-n-in "bugz" 2 3) -> (#f "bugz" #f)
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This is a procedure used to generate proto-wheels that are merged together into a larger proto-wheel using generate-wheel.
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### generate-wheel combine proto-wheels ...
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Combines proto-wheels using the combine procedure and returns a new, larger proto-wheel:
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(define fizz '(every-n-in "fizz" 3))
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(define buzz '(every-n-in "buzz" 5))
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(define (combine . args)
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(let ((args (filter values args)))
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(if (null? args)
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#f
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(apply string-append args))))
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(define proto-wheel (generate-wheel combine fizz buzz))
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Proto-wheel can now be converted to a circular list or a vector depending on your needs. Most people will probably convert it to a circular-list, but wheels _can_ grow prohibitively large and using a vector might fit more into the cpu cache. The fizzbuzz wheel is just 15 elements long. A fizz-buzz-bar (where bar is instead of multiples of 7) is 105 elements long. fizz-buzz-bar-quux (quux instead of 11) means 1155 elements.
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## How fast was your fizzbuzz
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How does our fizzbuzz fare against a naive implementation? Using the code in example.scm (both procedures generate lists of fizzy and buzzy goodness) these are my numbers:
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scheme@(guile-user)> ,time (car (regular-fizzbuzz 10000000))
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$26 = 1
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;; 1.161756s real time, 1.242915s run time. 0.314005s spent in GC.
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scheme@(guile-user)> ,time (car (wheel-fizzbuzz 10000000))
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$27 = 1
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;; 0.528079s real time, 0.614268s run time. 0.312021s spent in GC.
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It can of course be done faster, but not necessarily in such a simple way. The wheel version is also trivially extensible if you are unsure about your future fizzbuzzing needs.
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## Todo
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It would be fun to be able to generate step wheels, like for example a prime wheel where we can just skip large parts of the number line.
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## Licence
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a simplified ISC. Non of that big-letter stuff matters in my jurisdiction, so I removed it. You may use it under regular ISC if you please.
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