Unusual syntax JSON parse problem String (Clojure)

Question

I have a long clojure String (java.lang.String) representing a JSON. It has \"normal\" looking syntax like so:

\"{ a:1, b:\"hello\" }\"

The key

Answer 1

Update 2019-3-21

The link from @jas includes a comment that "it looks like YAML" (if the colons are followed by a space).

I have integrated the new snakeyaml-engine library into the Tupelo Library. API docs are here. The answer is now super-simple:

(ns tst.demo.core
  (:use demo.core tupelo.core tupelo.test)
  (:require [tupelo.parse.yaml :as yaml] ))

(dotest
  (let [data-1 "{ a: 1, b: 'Hello World' }"]
    (is= (yaml/parse data-1) {:a 1, :b "Hello World"})))

---

Old Answer

Given project.clj

 [io.forward/yaml "1.0.9"]

this works:

(ns tst.demo.core
  (:require [yaml.core :as yaml]) )

(def data-1 "{ a: 1, b: \"Hello World\" }" )

  (let [result-raw (yaml/parse-string data-1)
        result     (into {} result-raw)]

with result

----------------------------------
   Clojure 1.10.0    Java 10.0.1
----------------------------------

Testing tst.demo.core
result-raw   => #ordered/map ([:a 1] [:b "Hello World"])
result       => {:a 1, :b "Hello World"}

Unfortunately it (currently) fails under Java 11 because a dependent library needs a type hint. You can work around this by fixing up your project.clj:

  :dependencies [
     [io.forward/yaml "1.0.9" :exclusions [org.flatland/ordered
                                           org.yaml/snakeyaml] ]
     [org.yaml/snakeyaml "1.23"]
     [org.flatland/ordered "1.5.7"]
     [org.clojure/clojure "1.10.0"]

I filed an issue with the io.forward/yaml project to update their dependencies.

Answer 2

Depending on your level of desperation, the Groovy JSON Slurper can read this "JSON" in the LAX setting (which allows those attributes, comments, ...)

Add the following dep:

[org.codehaus.groovy/groovy-json "2.5.6"]

Then you can run:

user=> (import [groovy.json JsonSlurper JsonParserType])
groovy.json.JsonParserType
user=> (def parser (doto (JsonSlurper.) (.setType JsonParserType/LAX)))
#'user/parser
user=> (def data (.parseText parser "{ a:1, b:\"hello\" }"))
#'user/data
user=> data
{"a" 1, "b" "hello"}