CIDER provides intelligent code completion for both source buffers (powered by
cider-mode
) and REPL buffers.
Note
Internally CIDER leverages compliment for Clojure and cljs-tooling for ClojureScript. Improvements to the two libraries automatically translate to improvements in CIDER.
Standard completion
Out-of-the box CIDER uses the standard Emacs tooling for code completion. When you press TAB or M-TAB you'll get completion candidates in a dedicated buffer.
Auto-completion
CIDER users are advised to use company-mode
to enable auto-completion inside of source code and REPL buffers. To install
company-mode
do:
M-x package-install
RET company
RET
After installation, company can be turned on globally, like so --
(global-company-mode)
-- or through mode-specific hooks:
(add-hook 'cider-repl-mode-hook #'company-mode)
(add-hook 'cider-mode-hook #'company-mode)
When company-mode
is thus enabled, it will receive completion information
from cider-complete-at-point
, and requires no additional setup or plugins.
If you'd prefer to trigger completions manually you can add this to you config:
(setq company-idle-delay nil) ; never start completions automatically
(global-set-key (kbd "M-TAB") #'company-complete) ; use M-TAB, a.k.a. C-M-i, as manual trigger
To make TAB complete, without losing the ability to manually indent, you can add this to your config:
(global-set-key (kbd "TAB") #'company-indent-or-complete-common)
Fuzzy candidate matching
By default company-mode
will provide completion candidates with the assumption
that whatever you've typed so far (e.g. map-
) is a completion prefix (meaning
you'd get only candidates that have map-
in the beginnings of their names).
You can get enhanced fuzzy completion with the CIDER-specific completion style
by adding:
(add-hook 'cider-repl-mode-hook #'cider-company-enable-fuzzy-completion)
(add-hook 'cider-mode-hook #'cider-company-enable-fuzzy-completion)
Now company-mode
will accept certain fuzziness when matching candidates
against the prefix. For example, typing mp
will show you map-indexed
as one
of the possible completion candidates, cji
will complete to clojure.java.io
,
etc. Different completion examples are
listed here.
Completion annotations
Completion candidates will be annotated by default with an abbreviation
corresponding to their type, and (contextually) their namespace. The function
used to format the annotation can be configured by
cider-annotate-completion-function.
The abbreviations used are configured by
cider-completion-annotations-alist
and the context in which their namespace is
included is configured by cider-completion-annotations-include-ns.
Tip
Completion annotations can be disabled by setting
cider-annotate-completion-candidates
to nil
.
Updating stale classes and methods cache
Sometimes, the completion fails to recognize new classes that came with
dependencies that were loaded dynamically after the REPL has started (e.g. via
Boot). Executing M-x cider-completion-flush-caches
(or going through the menu
CIDER Interaction->Misc->Flush completion cache
) forces the completion backend
to re-read all classes it can find on the classpath.