16 lines
408 B
Factor
16 lines
408 B
Factor
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! Copyright (C) 2006 Daniel Ehrenberg
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! See http://factorcode.org/license.txt for BSD license.
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IN: rot13
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USING: kernel math sequences strings ;
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: rotate ( ch base -- ch ) tuck - 13 + 26 mod + ;
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: rot-letter ( ch -- ch )
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{
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{ [ dup letter? ] [ CHAR: a rotate ] }
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{ [ dup LETTER? ] [ CHAR: A rotate ] }
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{ [ t ] [ ] }
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} cond ;
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: rot13 ( string -- string ) [ rot-letter ] map ;
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