Merge pull request #1223 from igrishaev/tag-nth-friendly

Provide a function to convert new parsing result to the old one

Author: opqdonut

README.md

@@ -2581,6 +2581,23 @@ Parsing returns tagged values for `:orn`, `:catn`, `:altn` and `:multi`.
 ;; => #malli.core.Tag{:key :malli.core/default, :value {:type "sized", :size 1}}
 ```
 
+The function `old-parse-format` transforms the new parsing format to the old
+one prior to version 0.18.0:
+
+```clojure
+(-> [:* [:catn
+         [:prop :string]
+         [:val [:altn
+                [:s :string]
+                [:b :boolean]]]]]
+    (m/parse ["-server" "foo" "-verbose" true "-user" "joe"])
+    (m/old-parse-format))
+
+[{:prop "-server" :val [:s "foo"]}
+ {:prop "-verbose" :val [:b true]}
+ {:prop "-user" :val [:s "joe"]}]
+```
+
 ## Unparsing values
 
 The inverse of parsing, using `m/unparse` and `m/unparser`:

src/malli/core.cljc

@@ -1,7 +1,7 @@
 (ns malli.core
   (:refer-clojure :exclude [eval type -deref deref -lookup -key assert])
   #?(:cljs (:require-macros malli.core malli.impl.util))
-  (:require #?(:clj [clojure.walk :as walk])
+  (:require [clojure.walk :as walk]
             [clojure.core :as c]
             [malli.impl.regex :as re]
             [malli.impl.util :as miu]
@@ -174,6 +174,18 @@
   "Is this a value constructed with `tags`?"
   [x] (instance? Tags x))
 
+(defn old-parse-format
+  "Transform the new parsing format to the old one by
+   replacing Tag and Tags objects with their content."
+  [parsed]
+  (walk/postwalk
+   (fn [x]
+     (cond
+       (tag? x) [(:key x) (:value x)]
+       (tags? x) (:values x)
+       :else x))
+   parsed))
+
 ;;
 ;; impl
 ;;

test/malli/core_test.cljc

@@ -1236,6 +1236,14 @@
 
       (is (true? (m/validate (over-the-wire schema) valid1)))
 
+      (testing "old parse format"
+        (let [tag (m/parse [:orn
+                            [:foo [:catn [:i :int] [:s :string]]]
+                            [:bar :uuid]]
+                           [1 "a"])
+              old (m/old-parse-format tag)]
+          (is (= [:foo {:i 1 :s "a"}] old))))
+
       (testing "ast"
         (is (= {:type :multi,
                 :keys {:sized {:order 0,