Support for multi-arity render fns (closes #23)

Author: tonsky

README.md

@@ -319,6 +319,7 @@ This is a detailed breakdown of what happens inside of Rum. By using `rum/defc`,
 ### 0.2.7
 
 - Allow components to refer to themselves (thx [Kevin Lynagh](https://github.com/lynaghk), pull request #30)
+- Support for multi-arity render fns (issue #23)
 
 ### 0.2.6
 

examples/examples.cljs

@@ -331,9 +331,13 @@
 
 ;; Self-referencing component
 
-(rum/defc tree [form]
-  (if (sequential? form)
-    [:.branch (map tree form)]
-    [:.leaf (str form)]))
+(rum/defc tree < rum/static
+  ([form] (tree form 0))
+  ([form depth]
+    (let [offset {:style {:margin-left (* 10 depth)}}]
+      (if (sequential? form)
+        [:.branch offset (map #(tree % (inc depth)) form)]
+        [:.leaf   offset (str form)]))))
 
 (rum/mount (tree [:a [:b [:c :d [:e] :g]]]) (el "selfie"))
+

src/rum.clj

@@ -2,6 +2,10 @@
   (:require
     [sablono.compiler :as s]))
 
+(defn- fn-body? [form]
+  (and (list? form)
+       (vector? (first form))))
+
 (defn- parse-defc [xs]
   (loop [res  {}
          xs   xs
@@ -11,20 +15,23 @@
       (cond
         (and (empty? res) (symbol? x))
           (recur {:name x} next nil)
-        (vector? x) (assoc res :argvec x
-                               :render next)
-        (string? x) (recur (assoc res :doc x) next nil)
-        (= '< x)    (recur res next :mixins)
+        (fn-body? xs)        (assoc res :bodies (list xs))
+        (every? fn-body? xs) (assoc res :bodies xs)
+        (string? x)          (recur (assoc res :doc x) next nil)
+        (= '< x)             (recur res next :mixins)
         (= mode :mixins)
           (recur (update-in res [:mixins] (fnil conj []) x) next :mixins)
         :else
           (throw (IllegalArgumentException. (str "Syntax error at " xs)))))))
 
+(defn- compile-body [[argvec & body]]
+  (list argvec (s/compile-html `(do ~@body))))
+
 (defn- -defc [render-ctor body]
-  (let [{:keys [name doc mixins argvec render]} (parse-defc body)]
+  (let [{:keys [name doc mixins bodies]} (parse-defc body)
+        render-fn (map compile-body bodies)]
    `(def ~name ~doc
-      (let [render-fn#    (fn ~argvec ~(s/compile-html `(do ~@render)))
-            render-mixin# (~render-ctor render-fn#)
+      (let [render-mixin# (~render-ctor (fn ~@render-fn))
             class#        (rum/build-class (concat [render-mixin#] ~mixins) ~(str name))
             ctor#         (fn [& args#]
                             (let [state# (args->state args#)]
@@ -72,3 +79,4 @@
                 (mapcat (fn [[k v]] [(props k) v])))]
     `(rum/element (ctor->class ~ctor) (args->state [~@as]) (cljs.core/js-obj ~@ps))))
 
+

target/main.js

@@ -20,5 +20,3 @@ input:focus { outline: 2px solid #a3ccf7; }
 .artboard { -webkit-user-select: none; line-height: 10px; }
 .art-cell { width: 12px; height: 12px; margin: 0 1px 1px 0; display: inline-block; background-color: #EEE; }
 .artboard .stats { font-size: 12px; line-height: 14px; margin-top: 8px; }
-
-.branch > .branch { margin-left: 20px; }