I can return a map from function with following syntax

```
(defn retmap [bar] { :foo bar })

```

How do I achieve the same with reader macro syntax? I tried following

```
(def retmap #({:foo %}))

```

But calling this function `(retmap)` gives the error

```
clojure.lang.ArityException: Wrong number of args (0) passed to: PersistentArrayMap

```