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Clear REPL Bufferλ︎

When large results are returned from Clojure code they can eventually cause a slow-down of Emacs. Clearing the REPL buffer can restore Emacs to its usual speedy self.

Auto-trimming of the REPL buffer automatically deletes the oldest output, based on a given size.

Use cider-inspector and Source Code buffers

, d v displays values in the cider-inspector allowing navigation of nested data structures and paging through large data sets. Portal data navigation tool is an external tool that also provides navigation and paging of data as well as other data visualisation.

Evaluation in a Clojure source code buffer are limited to 100 results so avoids potential slow-down from large results. Use , e p menu to pretty print the results of evaluations in a temporary buffer.

Clear the REPL buffer from any bufferλ︎

, s l to remove the output of the last evaluation from the REPL buffer, spacemacs/cider-find-and-clear-repl-buffer.

, s L clear all the output from the entire REPL session, cider-find-and-clear-repl-output.

In the REPL bufferλ︎

, s l to switch to the REPL buffer

In Evil Insert mode use the , menu to call commands to clear the REPL buffer:

clear to clear the whole buffer history

clear-output to clear the result of the last evaluation

Configure auto-trimmingλ︎

Auto-trimming is not enabled by default in CIDER, it must be set with a specific value.

Add the layer variable cider-repl-buffer-size-limit to have all Clojure projects auto-trim the REPL

     (clojure :variables
              clojure-enable-clj-refactor t
              clojure-enable-linters 'clj-kondo
              clojure-toplevel-inside-comment-form t
              cider-overlays-use-font-lock t
              cider-repl-buffer-size-limit 100)

Alternatively, add the cider-repl-buffer-size-limit to a .dir-locals.el to affect just one Clojure project

((clojure-mode . ((cider-repl-buffer-size-limit . 100))))

revert-buffer on a Clojure project to ensure Emacs has loaded the .dir-locals.el

Last update: December 22, 2022