parcera

Grammar-based Clojure(script) parser.

Parcera can safely read any Clojure file without any code evaluation.

Parcera uses the wonderful Antlr4 as its parsing engine and focuses on the grammar definition instead.

usage

• Java

Add [org.antlr/antlr4-runtime "4.7.1"] to your dependencies in addition to parcera. This is to avoid adding an unnecessary dependency for the JavaScript users.

• Javascript

All necessary files are delivered with parcera. However, currently only Browser support has been tested.

(ns example.core
  (:require [parcera.core :as parcera]))

;;parse clojure code from a string
(parcera/ast (str '(ns parcera.core
                     (:require [clojure.data :as data]
                               [clojure.string :as str]))))

;; => returns a data structure with the result from the parser
(:code
 (:list
  (:symbol "ns")
  (:whitespace " ")
  (:symbol "parcera.core")
  (:whitespace " ")
  (:list
   (:keyword ":require")
   (:whitespace " ")
   (:vector (:symbol "clojure.data") (:whitespace " ") (:keyword ":as") (:whitespace " ") (:symbol "data"))
   (:whitespace " ")
   (:vector (:symbol "clojure.string") (:whitespace " ") (:keyword ":as") (:whitespace " ") (:symbol "str")))))
   
;; get meta data from the parsed code
(meta (second (parcera/ast (str :hello))))
#:parcera.core{:start {:row 1, :column 0}, :end {:row 1, :column 6}}

;; convert an AST back into a string
(parcera/code [:symbol "ns"])
;; "ns"

If you are interested in the grammar definition check Clojure.g4.

contributing

• to get you setup check the travis file which already contains a full setup from scratch.
• the project contains a benchmark which should be the decision factor for performance issues.
• please follow Clojure's Etiquete for issues and pull requests