48 lines
1.9 KiB
Factor
48 lines
1.9 KiB
Factor
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! Rewritten by Matthew Willis, July 2006
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!
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! Copyright (C) 2004 Chris Double.
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!
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! Redistribution and use in source and binary forms, with or without
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! modification, are permitted provided that the following conditions are met:
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!
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! 1. Redistributions of source code must retain the above copyright notice,
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! this list of conditions and the following disclaimer.
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!
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! 2. Redistributions in binary form must reproduce the above copyright notice,
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! this list of conditions and the following disclaimer in the documentation
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! and/or other materials provided with the distribution.
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!
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! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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USING: lazy-lists math kernel sequences test ;
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IN: lazy-examples
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: naturals 0 lfrom ;
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: positves 1 lfrom ;
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: evens 0 [ 2 + ] lfrom-by ;
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: odds 1 lfrom [ 2 mod 1 = ] lsubset ;
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: powers-of-2 1 [ 2 * ] lfrom-by ;
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: ones 1 [ ] lfrom-by ;
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: squares naturals [ dup * ] lmap ;
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: first-five-squares 5 squares ltake list>array ;
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: divisible-by? ( a b -- bool )
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#! Return true if a is divisible by b
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mod 0 = ;
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: filter-multiples ( n list - list )
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#! Given a lazy list of numbers, filter multiples of n
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swap [ divisible-by? not ] curry lsubset ;
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: primes 2 lfrom [ filter-multiples ] lapply ;
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: first-ten-primes 10 primes ltake list>array ;
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