allow defmulti to be called without ctx

Author: borkdude

src/sci/impl/multimethods.cljc

@@ -3,6 +3,7 @@
   (:refer-clojure :exclude [defmulti defmethod])
   (:require
    #?(:clj [clojure.string :as str])
+   [sci.ctx-store :as store]
    [sci.impl.hierarchies :refer [global-hierarchy]]))
 
 #?(:clj (set! *warn-on-reflection* true))
@@ -44,7 +45,10 @@
   or the var special form)."
   {:arglists '([name docstring? attr-map? dispatch-fn & options])}
   [_ _ ctx mm-name & options]
-  (let [docstring   (if (string? (first options))
+  (let [[ctx mm-name options] (if (symbol? ctx)
+                                [nil ctx mm-name options]
+                                [ctx mm-name options])
+        docstring   (if (string? (first options))
                       (first options)
                       nil)
         options     (if (string? (first options))
@@ -71,7 +75,7 @@
 
     (let [options   (apply hash-map options)
           default   (get options :default :default)
-          hierarchy (get options :hierarchy (global-hierarchy ctx))]
+          hierarchy (get options :hierarchy (global-hierarchy (or ctx (store/get-ctx))))]
       (check-valid-options options :default :hierarchy)
       #?(:clj `(let [v# (def ~mm-name)]
                  (when-not (and (clojure.core/has-root-impl v#) (clojure.core/multi-fn?-impl (deref v#)))