CODEWITHSUNDEEP
clojureclojurescript
szymanowski
szymanowski

Reputation: 1379

Define my own reader macro in clojure

I would like to define my own reader macro in clojure:

(read-string "ßfoo")
=> (some_func :foo)

Is it possible?

Upvotes: 11

Views: 2082

Answers (2)

Leon Grapenthin
Leon Grapenthin

Reputation: 9266

It is possible to create tagged literals by having a reader map in data_readers.clj at the top of your classpath.

This must be in data_readers.clj at the top of your classpath (usually src directory).

{ß reader-demo.core/read-fn}

This goes into reader-demo.core

(defn some-func
  [arg]
  (str "some-func invoked with " arg))

(defn read-fn
  [arg]
  (-> arg
      keyword
      some-func))

Invoking

#ß foo

will return

"some-func invoked with :foo"

This technique is described here: The reader: Tagged literals

Notice that in practice you should namespace your tagged literals as all non-namespaced ones are reserved for Clojure itself.

Upvotes: 13

Chiron
Chiron

Reputation: 20245

Currently, Clojure doesn't allow to create user defined reader macros. This might/might not change in the future.

Upvotes: 0

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