Automatically decode from pathnames/streams in jget.

README.org

@@ -138,6 +138,10 @@ entry under key is found (like in ~gethash~).
   (njson:jget #p"/second-key/0" data)
   ;; => 1, T
 
+  ;; Can decode and index files as an alias for `njson:decode'.
+  (njson:jget #(0 "kind") #p"tests/baker.json")
+  ;; "Listing"
+
   ;; Modify the element in place:
   (setf (njson:jget #p"/second-key/0" data) 3)
   ;; Another indexing syntax, for no particular reason:

functions.lisp

@@ -112,6 +112,10 @@ CHAR is left unread on STREAM after returning."
     (cerror "Return nothing"
             'non-indexable :value object)
     (values nil nil))
+  (:method (key (object pathname))
+    (jget* key (decode-from-file object)))
+  (:method (key (object stream))
+    (jget* key (decode-from-stream object)))
   (:method ((key string) (object string))
     (declare (ignore key))
     (cerror "Return nothing"
@@ -137,6 +141,13 @@ KEY-OR-INDEX can be
 - a sequence of integers and strings (to index the nested structures).
 - an empty sequence/pathname (to match the whole object).
 
+OBJECT can be
+- A hash table, indexed by strings
+- An array, indexed by integers
+- A stream, which is `decode'd and then indexed
+- A pathname, which is `decode'd and then indexed
+- Anything else, considered an error (see below)
+
 Return two values: the value under KEY-OR-INDEX and whether this value
 was found.
 

tests/tests.lisp

@@ -235,3 +235,15 @@
       ;; (assert-no-key #(("data" ("parents" _))))
       ;; (assert-no-key #(("data" ("parents" ("nested" :true)))))
       )))
+
+(define-test inline-decode-file/stream ()
+  (let* ((baker-file (asdf:system-relative-pathname :njson "tests/baker.json"))
+         (baker-stream (open baker-file))
+         (baker-decoded (decode baker-file)))
+    (assert-equal "Henry Baker: Meta-circular semantics for Common Lisp special forms"
+                  (jget #(0 "data" "children" 0 "data" "title") baker-decoded))
+    (assert-equal "Henry Baker: Meta-circular semantics for Common Lisp special forms"
+                  (jget #(0 "data" "children" 0 "data" "title") baker-file))
+    (assert-equal "Henry Baker: Meta-circular semantics for Common Lisp special forms"
+                  (jget #(0 "data" "children" 0 "data" "title") baker-stream))
+    (close baker-stream)))