# How to avoid defmulti being defonce with the REPL session?
**URL:** https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000
**Category:** How to?
**Tags:** macros
**Created:** [March 16, 2019, 4:46pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000 "2019-03-16T16:46:29Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Webdev\_Tory](https://clojureverse.org/u/Webdev_Tory)
#### Post date: [March 16, 2019, 4:46pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/1 "2019-03-16T16:46:29Z")
(note: using Cider)
I use defmulti and defmethod in my code, `eval-buffer`, and test them. They have an error, so I rewrite them (change them to receive a map instead of sequential args). However, `eval-buffer` won’t update the definition; only restarting the repl session seems to capture my changes. Is there a way to cause macros like defmulti to reload without restarting my repl?
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### Author:  [@pesterhazy](https://clojureverse.org/u/pesterhazy)
#### Post date: [March 16, 2019, 5:06pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/2 "2019-03-16T17:06:28Z")
`defmulti` defaults to defonce semantics. Add a `def` before the `defmulti` declaration to get def semantics instead:
```auto
(def foo nil)
(defmulti foo (fn [n m] n))
(defmethod foo :default [n m] (prn [:n n]))
```
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### Author:  [@Webdev\_Tory](https://clojureverse.org/u/Webdev_Tory)
#### Post date: [March 16, 2019, 5:27pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/3 "2019-03-16T17:27:30Z")
Does this work with all macros?
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### Author:  [@pesterhazy](https://clojureverse.org/u/pesterhazy)
#### Post date: [March 16, 2019, 6:45pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/4 "2019-03-16T18:45:24Z")
`defmulti` is indeed a macro but so far as I can see whether or not it’s implemented as a macro is not relevant to its reevaluation behavior.
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### Author:  [@plexus](https://clojureverse.org/u/plexus)
#### Post date: [March 16, 2019, 7:16pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/5 "2019-03-16T19:16:28Z")
Indeed, defmulti does this because otherwise reevaluating the defmulti would invalidate all the corresponding defmethods.
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### Author:  [@didibus](https://clojureverse.org/u/didibus)
#### Post date: [March 17, 2019, 10:14pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/6 "2019-03-17T22:14:39Z")
Oh, interesting. I always thought it was an issue because of class generation. I’m not sure I totally follow the logic, like, what scenario would it be a problem? Since namespaces are loaded once only anyways.
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### Author:  [@HolyJak](https://clojureverse.org/u/HolyJak)
#### Post date: [March 19, 2019, 12:02pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/7 "2019-03-19T12:02:25Z")
Perhaps [https://github.com/clojure/tools.namespace#reloading-code-motivation](https://github.com/clojure/tools.namespace#reloading-code-motivation) could help? It mentions defmulti so I suppose it works with that.
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### Author:  [@orestis](https://clojureverse.org/u/orestis)
#### Post date: [March 19, 2019, 2:46pm UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/8 "2019-03-19T14:46:36Z")
What about clojurescript where everything is reloaded when a file changes? Any tips on handling this? I vaguely remember seeing something like:
```auto
(def cool-multi nil)
(defmethod cool-multi ,,,)
```
But I’m not sure if that was the right thing to do or not.
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### Author:  [@system](https://clojureverse.org/u/system)
#### Post date: [September 18, 2019, 2:46am UTC](https://clojureverse.org/t/how-to-avoid-defmulti-being-defonce-with-the-repl-session/4000/9 "2019-09-18T02:46:38Z")
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