20 lines
563 B
Factor
20 lines
563 B
Factor
USING: kernel math sequences ;
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IN: sequences-contrib
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! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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: 3nth ( n seq -- slice ) >r dup 3 + r> <slice> ;
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! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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: map3-i ( seq -- i ) length 2 - ;
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: map3-quot ( quot -- quot ) [ swap 3nth ] swap append ;
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: map3 ( seq quot -- seq ) over map3-i swap map3-quot map-with ;
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! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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: last ( seq -- elt ) dup length 1- swap nth ;
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PROVIDE: contrib/sequences ; |