... sub-trees that haven't changed? Thus you can collate two trees (for all the usual purposes: all the nontrivial boolean functions: and ior xor eqv nand nor andc1 andc2 orc1 orc2; all the nontrivial predicates: equal notequal subset notsubset backsubset notbacksubset eithersubset neithersubset) making just one pass over most/all of the nodes (in some cases you can skip a whole sub-...

...any sub-trees that haven't changed? Thus you can collate two trees (for all the usual purposes: all the nontrivial boolean functions: and ior xor eqv nand nor andc1 andc2 orc1 orc2; all the nontrivial predicates: equal notequal subset notsubset backsubset notbacksubset eithersubset neithersubset) making just one pass over most/all of the nodes (in some cases you can skip a whole sub-tree in ...