Allow JSON parser functions to return alists

* src/json.c (Fjson_parse_string, Fjson_parse_buffer): Give these
functions a keyword argument to specify the return type for JSON
objects.
(json_to_lisp): Convert objects to alists if requested.
(json_parse_object_type): New helper function to parse keyword
arguments.

* test/src/json-tests.el (json-parse-string/object): Add a unit test.

* doc/lispref/text.texi (Parsing JSON): Document new functionality.

1 files changed, 9 insertions, 7 deletions

diff --git a/test/src/json-tests.el b/test/src/json-tests.el
index 551f8ac5fe4..100bf7bd39b 100644
--- a/test/src/json-tests.el
+++ b/test/src/json-tests.el
@@ -54,13 +54,15 @@
 
 (ert-deftest json-parse-string/object ()
   (skip-unless (fboundp 'json-parse-string))
-  (let ((actual
-         (json-parse-string
-          "{ \"abc\" : [1, 2, true], \"def\" : null, \"abc\" : [9, false] }\n")))
-    (should (hash-table-p actual))
-    (should (equal (hash-table-count actual) 2))
-    (should (equal (cl-sort (map-pairs actual) #'string< :key #'car)
-                   '(("abc" . [9 :false]) ("def" . :null))))))
+  (let ((input
+         "{ \"abc\" : [1, 2, true], \"def\" : null, \"abc\" : [9, false] }\n"))
+    (let ((actual (json-parse-string input)))
+      (should (hash-table-p actual))
+      (should (equal (hash-table-count actual) 2))
+      (should (equal (cl-sort (map-pairs actual) #'string< :key #'car)
+                     '(("abc" . [9 :false]) ("def" . :null)))))
+    (should (equal (json-parse-string input :object-type 'alist)
+                   '((abc . [9 :false]) (def . :null))))))
 
 (ert-deftest json-parse-string/string ()
   (skip-unless (fboundp 'json-parse-string))