22 lines
879 B
Factor
22 lines
879 B
Factor
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USING: arrays kernel locals math sequences ;
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IN: sequences.extras
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: reduce1 ( seq quot -- result ) [ unclip ] dip reduce ; inline
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:: reduce-r
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( list identity quot: ( obj1 obj2 -- obj ) -- result )
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list empty?
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[ identity ]
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[ list rest identity quot reduce-r list first quot call ] if ;
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inline recursive
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! Quot must have static stack effect, unlike "reduce"
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:: reduce* ( seq id quot -- result ) seq
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[ id ]
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[ unclip id swap quot call( prev elt -- next ) quot reduce* ] if-empty ; inline recursive
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:: combos ( list1 list2 -- result ) list2 [ [ 2array ] curry list1 swap map ] map concat ;
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: (head-slice) ( seq n -- seq' ) over length over < [ drop ] [ head-slice ] if ;
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: find-all ( seq quot -- elts ) [ [ length iota ] keep ] dip
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[ dupd call( a -- ? ) [ 2array ] [ 2drop f ] if ] curry 2map [ ] filter ; inline
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: empty ( seq -- ) 0 swap shorten ;
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