specter 2022-04-08 | Slack Archive

onetom04:04:31

would it be possible to do the following sequence of multi-transform & select-one in one step? that would allow me to package up this transform/select operation as a path (instead of a function), so it can be combined with further processing.

(->> {:cols [10 20 30]
        :rows [[1 2 3]
               [4 5 6]]}
       (sp/multi-transform
         [(collect-one :cols)
          :rows ALL (terminal (partial mapv +))])
       (sp/select-one :rows))
=> [[11 22 33] [14 25 36]]

equivalent clojure code:

(->> {:cols [10 20 30]
        :rows [[1 2 3]
               [4 5 6]]}
       ((fn [{:keys [cols rows]}]
          (mapv
            (fn [cells]
              (mapv + cells cols))
            rows))))
=> [[11 22 33] [14 25 36]]

onetom05:04:38

in more abstract terms, i want to 1. select from the input structure 2. transform the selected part 3. combine the transformed part with another selected and transformed part of the original structure i can of course do all this in a regular clojure function, which i can compose with further select/transform operations via view, but do i have to?

onetom05:04:56

i have the feeling, that im missing some navigator, so i can do this kind of multi collection map operation. both view and transformed doesn't receive the collected values. terminal / vterminal does receive collected values, but also the currently navigated value too, so i have to wrap clojure.core functions to ignore that last argument. collected? receives all collected values, both individually or as a single vector, but it's return value is not used to replace the value, we are currently navigated to.

onetom05:04:59

i think i wish for something like transformed-with-collected, so i can do the following:

(->> {:cols [10 20 30]
        :rows [[1 2 3]
               [4 5 6]]}
       (sp/select-one
         [(collect-one :cols)
          :rows 
          (transformed-with-collected ALL (partial mapv +))
          DISPENSE]))

2022-04-08

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