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Un-define expressionsλ︎

def, defn names change during development, especially when code is refactored. Un-define removes unwanted vars and keeps the REPL clean and avoids the need to restart the REPL.

, e u (cider-undef) un-defines the current function name or var, e.g. defn/def / deftest, removing it from the running REPL.

When cursor is not on a function name or any var, the mini-buffer prompts for the name to undefine.

Hint::Cider refresh or restart for multiple changesλ︎

Refresh or restart the REPL when there are multiple changes made to a namespace or across multiple namespaces.

Undefine tests before refactorλ︎

If the name of an existing test is changed, the original test will still run when calling the cider test commands. This can lead to confusing test results.

, e u on the deftest expression before changing its name will ensure that the existing test is removed from the REPL and no longer run.

Undefine in the REPL bufferλ︎

, undef in the REPL buffer (Vim Insert / Emacs state) prompts for a symbol to undefine.

TAB when typing the symbol name will popup a list of matching symbols available in the REPL. Select the name you wish to undef

Spacemacs Clojure REPL undef symbol helm narrowing

Undefine using Clojureλ︎

ns-unmap will remove a symbol from the running REPL. Use *ns* dynamic variable to represent the current namespace.

(ns-unmap *ns* 'name-before-refactor)

Or specify the namespace if the symbol is not in the current namespace

(ns-unmap 'practicalli.service 'name-before-refactor)

ns-unalias will remove an alias added via a require form

;; Require a neamespace
(require '[practicalli.service :as service])

;; The service alias should now be in the current nammespace
(ns-aliases *ns*)
;; => {service #namespace[practicalli.service]}

(ns-unalias *ns* 'service)
;; => nilλ︎

refresh function scans all directories on the classpath for source files, read their ns forms, builds a graph of their dependencies and load them in dependency order. set-refresh-dirs defines directories that should be scanned.

Add the library as a dependency to the project file

org.clojure/tools.namespace {:mvn/version "1.2.0"}

Require the namespace and refer the function (refresh is the only public function in the namespace)

(require '[ :refer [refresh]])

Refresh the current namespace


The refresh function will load all namespaces found and list them as the output.

:reloading (com.example.util

All Code must be loadable

If there are errors in one or more namespaces that prevent them from successfully loading, then reresh will error, showing which namespaces had issues to resolve.

Use refresh in a rich comment blockλ︎

Use a rich comment block to ensure the refresh function is only called when directly evaluated.

Code inside the rich comment block will not be evaluated when evaluating the current buffer or loading the namespace.


  (require '[ :refer [refresh]])


Last update: December 25, 2022