clojung

Deep introspection and transformation of data

About

Clojung is a library for concisely querying and updating nested data structures. One way to think of it is "get-in" and "assoc-in" on steroids. It is similar to the concept of a "lens" in functional programming, though it has some important extensions.

How to use

;; explain basic usage ;; explain structurepath interface ;; explain how structurepath can be extended (I've done it for working with directed acyclic graphs) - show implementations for ALL, VAL, LAST, etc. ;; explain precompiling to make things far faster

From a sequence of maps get all the even values for :a keys:

>>> (select [ALL :a even?] [{:a 1} {:a 2} {:a 4} {:a 3}])
[2 4]

In a sequence of maps increment all the even values for :a keys:

(update [ALL :a even?] inc [{:a 1} {:a 2} {:a 4} {:a 3}]) [{:a 1} {:a 3} {:a 5} {:a 3}]

Increment the last odd number in a sequence:

>>> (update [(filterer odd?) LAST] inc [2 1 6 9 4 8])
[2 1 6 10 4 8]

For all maps in a sequence, add the value of :b key to the value of :a key, but only if the :a value is even:

>>> (update [ALL (val-selector-one :b) :a even?] + [{:a 1 :b 3} {:a 2 :b -10} {:a 4 :b 10} {:a 3}])
[{:b 3, :a 1} {:b -10, :a -8} {:b 10, :a 14} {:a 3}]

Future work

;; parallelize the transformations ;; any connection to transducers?