DXML-62: add :xml/... shorthand namespace

Author: bendlas

src/main/clojure/clojure/data/xml/name.cljc

@@ -74,8 +74,9 @@
     (if-let [ns (namespace kw)]
       (if (.startsWith ns "xmlns.")
         (decode-uri (subs ns 6))
-        (if (= "xmlns" ns)
-          xmlns-uri
+        (case ns
+          "xmlns" xmlns-uri
+          "xml" xml-uri
           (throw (ex-info "Keyword ns is not an xmlns. Needs to be in the form :xmlns.<encoded-uri>/<local>"
                           {:kw kw}))))
       "")))

src/test/clojure/clojure/data/xml/test_emit.clj

@@ -239,6 +239,8 @@
   (is (= (emit-str {:tag :el :attrs {:xmlns/xmlns "http://www.w3.org/2000/xmlns/"}})
          "<?xml version=\"1.0\" encoding=\"UTF-8\"?><el/>"))
   (is (= (emit-str {:tag :el :attrs {:xmlns/xml "http://www.w3.org/XML/1998/namespace" ::xml/lang "en"}})
+         "<?xml version=\"1.0\" encoding=\"UTF-8\"?><el xml:lang=\"en\"/>"))
+  (is (= (emit-str {:tag :el :attrs {:xml/lang "en"}})
          "<?xml version=\"1.0\" encoding=\"UTF-8\"?><el xml:lang=\"en\"/>")))
 
 (deftest test-empty-elements