diff --git a/extra/sequences/extras/extras-tests.factor b/extra/sequences/extras/extras-tests.factor index 2ef0bfe15f..1c9a376ca3 100644 --- a/extra/sequences/extras/extras-tests.factor +++ b/extra/sequences/extras/extras-tests.factor @@ -72,4 +72,5 @@ IN: sequences.extras.tests { 8 } [ 3 iota dup [ 1 + * ] 2map-sum ] unit-test { 4 } [ "hello" "jello" [ = ] 2count ] unit-test -{ "ADEBFC" } [ { "ABC" "D" "EF" } round-robin ] unit-test +{ { } } [ { } round-robin ] unit-test +{ "ADEBFC" } [ { "ABC" "D" "EF" } round-robin >string ] unit-test diff --git a/extra/sequences/extras/extras.factor b/extra/sequences/extras/extras.factor index 0759d8172f..b84955d843 100644 --- a/extra/sequences/extras/extras.factor +++ b/extra/sequences/extras/extras.factor @@ -184,15 +184,12 @@ PRIVATE> : 2count ( ... seq1 seq2 quot: ( ... elt1 elt2 -- ... ? ) -- ... n ) [ 1 0 ? ] compose 2map-sum ; inline -:: round-robin-as ( seqs exemplar -- newseq ) - seqs length :> len - 0 0 seqs sum-lengths [ - f [ - drop dup len >= [ drop 1 + 0 ] when - 2dup seqs nth-unsafe ?nth - [ 1 + ] [ dup not ] bi* - ] loop - ] exemplar replicate-as 2nip ; +: max-lengths ( seq -- n ) + [ length ] [ max ] map-reduce ; -: round-robin ( seqs -- newseq ) - [ { } ] [ dup first round-robin-as ] if-empty ; +: round-robin ( seq -- newseq ) + [ { } ] [ + dup [ max-lengths ] [ length ] bi [ iota ] bi@ + [ [ 2array ] with map ] curry map concat swap + [ [ first2 ] dip nth-unsafe ?nth ] curry map sift + ] if-empty ;