42 lines
1.4 KiB
Markdown
42 lines
1.4 KiB
Markdown
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# clojung
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Deep introspection and transformation of data
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# About
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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.
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# How to use
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;; explain basic usage
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;; explain structurepath interface
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;; explain how structurepath can be extended (I've done it for working with directed acyclic graphs)
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- show implementations for ALL, VAL, LAST, etc.
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;; explain precompiling to make things far faster
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From a sequence of maps get all the even values for :a keys:
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```clojure
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>>> (select [ALL :a even?] [{:a 1} {:a 2} {:a 4} {:a 3}])
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[2 4]
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```
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In a sequence of maps increment all the even values for :a keys:
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>>> (update [ALL :a even?] inc [{:a 1} {:a 2} {:a 4} {:a 3}])
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[{:a 1} {:a 3} {:a 5} {:a 3}]
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Increment the last odd number in a sequence:
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```clojure
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>>> (update [(filterer odd?) LAST] inc [2 1 6 9 4 8])
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[2 1 6 10 4 8]
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```
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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:
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```clojure
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>>> (update [ALL (val-selector-one :b) :a even?] + [{:a 1 :b 3} {:a 2 :b -10} {:a 4 :b 10} {:a 3}])
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[{:b 3, :a 1} {:b -10, :a -8} {:b 10, :a 14} {:a 3}]
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```
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# Future work
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;; parallelize the transformations
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;; any connection to transducers?
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