`collect-sum``#!optional`(`sentinel``0`)procedure`collect-product``#!optional`(`sentinel``1`)procedureThese collectors will compute the sum / product of the items being transduced, as if by applying

`+`or`*`respectively to the arguments.(import transducers) (transduce list-fold values (collect-sum 100) (list 2 4 6)) ; => 112 (transduce list-fold values (collect-product -1) (list 1 3 5)) ; => -15