70 lines
1.9 KiB
Factor
70 lines
1.9 KiB
Factor
! Copyright (C) 2008, 2009 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: make namespaces sequences kernel fry arrays compiler.utilities
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math accessors circular grouping combinators sorting math.order ;
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IN: splitting.monotonic
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<PRIVATE
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: ,, ( obj -- ) building get last push ;
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: v, ( -- ) V{ } clone , ;
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: ,v ( -- ) building get dup last empty? [ dup pop* ] when drop ;
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: (monotonic-split) ( seq quot -- newseq )
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[
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[ dup unclip suffix ] dip
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v, '[ over ,, @ [ v, ] unless ] 2each ,v
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] { } make ; inline
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PRIVATE>
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: monotonic-split ( seq quot -- newseq )
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over empty? [ 2drop { } ] [ (monotonic-split) ] if ; inline
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<PRIVATE
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: (monotonic-slice) ( seq quot class -- slices )
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[
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dupd '[
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[ length iota ] [ ] [ <circular> 1 over change-circular-start ] tri
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[ @ not [ , ] [ drop ] if ] 3each
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] { } make
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dup empty? [ over length 1 - prefix ] when -1 prefix 2 clump
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swap
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] dip
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'[ first2 [ 1 + ] bi@ _ _ boa ] map ; inline
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PRIVATE>
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: monotonic-slice ( seq quot class -- slices )
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pick length {
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{ 0 [ 2drop ] }
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{ 1 [ nip [ 0 1 rot ] dip boa 1array ] }
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[ drop (monotonic-slice) ]
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} case ; inline
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TUPLE: downward-slice < slice ;
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TUPLE: stable-slice < slice ;
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TUPLE: upward-slice < slice ;
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: downward-slices ( seq -- slices )
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[ > ] downward-slice monotonic-slice [ length 1 > ] filter ;
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: stable-slices ( seq -- slices )
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[ = ] stable-slice monotonic-slice [ length 1 > ] filter ;
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: upward-slices ( seq -- slices )
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[ < ] upward-slice monotonic-slice [ length 1 > ] filter ;
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: trends ( seq -- slices )
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dup length {
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{ 0 [ ] }
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{ 1 [ [ 0 1 ] dip stable-slice boa ] }
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[
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drop
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[ downward-slices ]
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[ stable-slices ]
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[ upward-slices ] tri 3append [ from>> ] sort-with
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]
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} case ;
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