! { [ dup 0 = ] [ 2drop { { } } ] }\r
! { [ over empty? ] [ 2drop { } ] }\r
! { [ t ] [ \r
-! [ [ 1- (combinations) ] [ drop first ] 2bi prefix-each ]\r
+! [ [ 1 - (combinations) ] [ drop first ] 2bi prefix-each ]\r
! [ (combinations) ] 2bi append\r
! ] }\r
! } cond ;\r
{ [ over 1 = ] [ 3drop columnize ] }\r
{ [ over 0 = ] [ 2drop 2drop { } ] }\r
{ [ 2dup < ] [ 2drop [ 1 cut ] dip \r
- [ 1- among [ append ] with map ] \r
+ [ 1 - among [ append ] with map ] \r
[ among append ] 2bi\r
] }\r
{ [ 2dup = ] [ 3drop 1array ] }\r