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47 lines
1.5 KiB
Markdown
47 lines
1.5 KiB
Markdown
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### Remarks
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Run the program under a platform that `/dev/dsp` is available.
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For example, if you are using pulseaudio, use `padsp`:
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padsp ruby entry.rb
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Please see Limitation if you want to run this program on os x.
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I confirmed the following platforms.
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* ruby 2.0.0p0 (2013-02-24 revision 39474) [x86\_64-linux]
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* ruby 1.9.3p194 (2012-04-20 revision 35410) [x86\_64-linux]
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* ruby 1.9.3p327 (2012-11-10 revision 37606) [x86\_64-darwin10.8.0]
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For those who are lazy, I'm attaching a screencast.
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### Description
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This program is a music-box quine.
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It prints itself with playing "Jesu, Joy of Man's Desiring".
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### Internal
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Like a real music box, this program consists of a mechanical part (code) and a piano roll.
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In the piano roll, `#` represents a pin that hits a note, and `|` represents a slur.
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The leftmost column corresponds 110Hz (low A).
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Every column corresponds a semitone higher than the left one.
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This program uses [the frequency modulation synthesis](http://en.wikipedia.org/wiki/Frequency_modulation_synthesis) to play the sound like a music-box.
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You can create a different-sounding tone by changing the parameter.
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For example, the following will play the sound like a harpsichord.
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padsp ruby entry.rb 2.0
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Note that this program does *not* use an idiom to remove whitespace, such as `.split.join`. All newlines and spaces do not violate any of the Ruby syntax rules.
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### Limitation
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On os x, `/dev/dsp` is not available.
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You have to use sox by replacing the following part:
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open("/dev/dsp","wb")
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with:
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IO.popen("./pl","wb")
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