mb structures Sections GenAutomata Doc

Def filter(P;l) == reduce(a,v. if P(a) [a / v] else v fi;nil;l)

is mentioned by

Def < tr > _tg == filter(e.tag(E)(e) = tg;tr)[tag_sublist]

In prior sections: mb list 1 mb list 2

Try larger context: GenAutomata

mb structures Sections GenAutomata Doc