: phi-inputs ( max-d-in pairs -- newseq )
dup empty? [ nip ] [
- swap '[ , _ first2 unify-inputs ] map
+ swap '[ [ , ] dip first2 unify-inputs ] map
pad-with-bottom
] if ;
] if-empty ;
: branch-variable ( seq symbol -- seq )
- '[ , _ at ] map ;
+ '[ [ , ] dip at ] map ;
: active-variable ( seq symbol -- seq )
[ [ terminated? over at [ drop f ] when ] map ] dip