Wharf

/(h)wôrf/ A level area to which a ship may be moored to load and unload.

Wharf is a Clojure library for transforming map keys. It uses clojure.walk/postwalk and comes bundled with many key transformers. The use case that pushed Wharf into existence is to be able to subscribe to and publish JSON APIs with out littering your Clojure code with underscores and camel case variables.

Usage

The following examples assume wharf.core is required.

(require '[wharf.core :refer :all])

The main function is transform-keys, which will walk the provided collection and trasnform all the keys using the provided function.

(transform-keys clojure.string/upper-case {"foo" "bar"})
;=> {"FOO" "bar"}

The function you pass in can be any function that accepts one argument. The example below uses the keyword function.

(transform-keys keyword {"foo" "bar" "goo" "gar"})
;=> {:foo "bar", :goo "gar"}

One common idiom is to compose functions.

(transform-keys (comp keyword uncapitalize) {"Foo" "bar"})
;=> {:foo "bar"}

There are also some case-conversion functions available.

(transform-keys camel->hyphen {"FooBar" "baz"})
;=> {"foo-bar" "baz"}

Here is how you would convert a camel-case string to a dash-case keyword and vice versa.

(transform-keys (comp keyword clojure.string/lower-case camel->hyphen) {"FooBar" "baz"})
;=> {:foo-bar "baz"}

(transform-keys (comp hyphen->upper-camel name) {:foo-bar "baz"})
;=> {"FooBar" "baz"}

A complex example.

(transform-keys (comp keyword clojure.string/lower-case camel->hyphen)
                {"FooBar" [{"Fancy1" nil "R2D2" nil} {"MoreNo1se" nil}]})
;=> {:foo-bar [{:fancy1 nil, :r2-d2 nil} {:more-no1se nil}]}

License

Copyright © 2014 Jeremy Heiler

Distributed under the Eclipse Public License, the same as Clojure.