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It appears that the operator forms he's talking about are things like Select[EvenQ], which would become "transducers" if I could do something like:

even_selector = Select[EvenQ]

incrementor = Map[Inc]

decrementor = Map[Dec]

even_incremented_selector = incrementor * even_selector (????)

odd_selector = even_incremented_selector * decrementor

even_selector[{1,2,3,4,5,6,7}] => {2,4,6}

even_incremented_selector[{1,2,3,4,5,6,7}] => {2,4,6,8}

odd_selector[{1,2,3,4,5,6,7}] => {1,3,5,7}

However I'm not entirely sure I've understood things correctly, I just stared at it for a while and need to get back to work...

(edit: HN does _not_ like formatting)




No, because all that is required for operator forms to do what you write is just ordinary function application. Which they already do just fine.

Rich is talking about something deeper, in which operators like filter become transformers that themselves operate on stateful processors (reducers) to produce new stateful processors that have incorporated the action described by the original operator.




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