first2 between? ;\r
\r
: all-intervals ( sequence -- intervals )\r
- [ >r dup number? [ dup 2array ] when r> ] { } assoc-map-as ;\r
+ [ [ dup number? [ dup 2array ] when ] dip ] { } assoc-map-as ;\r
\r
: disjoint? ( node1 node2 -- ? )\r
[ second ] [ first ] bi* < ;\r