25 lines
608 B
Factor
25 lines
608 B
Factor
! Copyright (C) 2006 Daniel Ehrenberg
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel math sequences strings io combinators ascii ;
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IN: rot13
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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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[ ]
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} cond ;
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: rot13 ( string -- string ) [ rot-letter ] map ;
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: rot13-demo ( -- )
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"Please enter a string:" print flush
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readln [
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"Your string: " write dup print
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"Rot13: " write rot13 print
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] when* ;
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MAIN: rot13-demo
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