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C-c C-k or C-c C-c

Save and evaluate the buffer in REPL.

With one C-u prefix, uses errortrace for improved stack traces. Otherwise follows the racket-error-context setting.

With two C-u prefixes, instruments code for step debugging. See racket-debug-mode and the variable racket-debuggable-files.

If point is within a Racket module form, the REPL "enters" that submodule (uses its language info and namespace).

When you run again, the file is evaluated from scratch -- the custodian releases resources like threads and the evaluation environment is reset to the contents of the file. In other words, like DrRacket, this provides the predictability of a "static" baseline, plus the ability to explore interactively using the REPL.

See also racket-run-and-switch-to-repl, which is even more like DrRacket's Run because it selects the REPL window (gives it the focus), too.

If your source file has a syntax or runtime error, a "skeleton" of your file is evaluated to get identifiers from module languages, requires, and definitions. That way, things like completion and racket-describe are more likely to work while you edit the file to fix the error. If not even the "skeleton" evaluation succeeds, you'll have only identifiers provided by racket/base, until you fix the error and run again.

Output in the *Racket REPL* buffer that describes a file and position is automatically "linkified". Examples of such text include:

  • Racket error messages.
  • rackunit test failure location messages.
  • prints of #<path> objects.

To visit these locations, move point there and press RET or mouse click. Or, use the standard next-error and previous-error commands.



Do racket <file> in *shell* buffer.


C-c C-o

Runs with profiling instrumentation and shows results.

Results are presented in a racket-profile-mode buffer, which also lets you quickly view the source code.

You may evaluate expressions in the REPL. They are also profiled. Use racket--profile-refresh to see the updated results. (In other words a possible workflow is: racket-profile a .rkt file, call one its functions in the REPL, and refresh the profile results.)

Caveat: Only source files are instrumented. You may need to delete compiled/*.zo files.


M-x racket-profile-mode

Major mode for results of racket-profile.

key             binding
---             -------

RET		racket--profile-visit
,		racket--profile-sort
g		racket--profile-refresh
n		racket--profile-next
p		racket--profile-prev
q		racket--profile-quit
z		racket--profile-show-zero

In addition to any hooks its parent mode special-mode might have run, this mode runs the hook racket-profile-mode-hook, as the final or penultimate step during initialization.


C-c C-l

Create the racket-logger-mode buffer and connect to logger output.

If the racket-repl-mode buffer is displayed in a window, split that window and put the logger in the bottom window. Otherwise, use pop-to-buffer.


M-x racket-logger-mode

Major mode for Racket logger output.

The customization variable racket-logger-config determines the levels for topics. During a session you may change topic levels using racket-logger-topic-level, bound to "l".

For more information see:

key             binding
---             -------

C-c		Prefix Command
g		racket-logger-clear
l		racket-logger-topic-level
n		racket-logger-next-item
p		racket-logger-previous-item
w		toggle-truncate-lines
x		racket-logger-exit

C-c C-z		racket-repl

In addition to any hooks its parent mode special-mode might have run, this mode runs the hook racket-logger-mode-hook, as the final or penultimate step during initialization.


M-x racket-debug-mode

Minor mode for debug breaks.

This feature is EXPERIMENTAL!!! It is likely to have significant limitations and bugs. You are welcome to open an issue to provide feedback. Please understand that this feature might never be improved -- it might even be removed someday if it turns out to have too little value and/or too much cost.

How to debug:

  1. "Instrument" code for step debugging. You can instrument entire files, and also individual functions.

    a. Entire Files

    Choose racket-run with two prefixes -- C-u C-u C-c C-c. The file will be instrumented for step debugging before it is run. Also instrumented are files determined by the variable racket-debuggable-files.

    The run will break at the first breakable position.

    Tip: After you run to completion and return to a normal REPL prompt, the code remains instrumented. You may enter expressions that evaluate instrumented code and it will break so you can step debug again.

    b. Function Definitions

    Put point in a function define form and C-u C-M-x to "instrument" the function for step debugging. Then in the REPL, enter an expression that causes the instrumented function to be run, directly or indirectly.

    You can instrument any number of functions.

    You can even instrument while stopped at a break. For example, to instrument a function you are about to call, so you can "step into" it:

     - M-. a.k.a. [`racket-visit-definition`](#racket-visit-definition).
     - C-u C-M-x to instrument the definition.
     - M-, a.k.a. [`racket-unvisit`](#racket-unvisit).
     - Continue stepping.

    Limitation: Instrumenting a function required from another module won't redefine that function. Instead, it attempts to define an instrumented function of the same name, in the module the REPL is inside. The define will fail if it needs definitions visible only in that other module. In that case you'll probably need to use entire-file instrumentation as described above.

  2. When a break occurs, the racket-repl-mode prompt changes. In this debug REPL, local variables are available for you to use and even to set!.

    Also, in the racket-mode buffer where the break is located, racket-debug-mode is enabled. This minor mode makes the buffer read-only, provides visual feedback -- about the break position, local variable values, and result values -- and provides shortcut keys:

key             binding
---             -------

SPC		racket-debug-step
?		racket-debug-help
c		racket-debug-continue
h		racket-debug-run-to-here
n		racket-debug-next-breakable
o		racket-debug-step-over
p		racket-debug-prev-breakable
u		racket-debug-step-out



<C-f5> or C-c C-t

Run the test submodule.

With prefix, runs with coverage instrumentation and highlights uncovered code.

Put your tests in a test submodule. For example:

(module+ test
  (require rackunit)
  (check-true #t))

rackunit test failure messages show the location. You may use next-error to jump to the location of each failing test.

See also:


M-x racket-raco-test

Do raco test -x <file> in *shell* buffer. To run 's test submodule.



C-c C-r

Send the current region (if any) to the Racket REPL.



Send the current definition to the Racket REPL.


C-x C-e

Send the previous sexp to the Racket REPL.

When the previous sexp is a sexp comment the sexp itself is sent, without the #; prefix.




Visit definition of symbol at point.

Use M-x racket-unvisit to return.

Please keep in mind the following limitations:

  • Only finds symbols defined in the current namespace. You may need to racket-run the current buffer, first.

  • Only visits the definition of module-level identifiers -- things for which Racket's identifier-binding function returns information. This does not include things such as local (nested) function definitions or racket/class member functions. To find those in the same file, you'll need to use a normal Emacs text search function like isearch-forward.

  • If the definition is found in Racket's #%kernel module, it will tell you so but won't visit the definition site.



Visit definition of module at point, e.g. net/url or "file.rkt".

Use M-x racket-unvisit to return.

Note: Only works if you've racket-run the buffer so that its namespace is active.

See also: racket-find-collection.



Return from previous racket-visit-definition or racket-visit-module.


C-c C-x C-f

Like Dr Racket's Open Require Path.

Type (or delete) characters that are part of a module path name. "Fuzzy" matches appear. For example try typing "t/t/r".

Choices are displayed in a vertical list. The current choice is at the top, marked with "->".

  • C-n and C-p move among the choices.
  • RET on a directory adds its contents to the choices.
  • RET on a file exits doing find-file.
  • C-g aborts.

Note: This requires Racket or newer. Otherwise it won't error, it will just never return any matches.


M-x racket-find-collection

Given a collection name, try to find its directory and files.

Takes a collection name from point (or, with a prefix, prompts you).

If only one directory is found, ido-find-file-in-dir lets you pick a file there.

If more than one directory is found, ido-completing-read lets you pick one, then ido-find-file-in-dir lets you pick a file there.

Note: This requires the raco-find-collection package to be installed. To install it, in shell enter:

raco pkg install raco-find-collection

Tip: This works best with ido-enable-flex-matching set to t. Also handy is the flx-ido package from MELPA.

See also: racket-visit-module and racket-open-require-path.



C-c C-.

Describe the identifier at point in a *Racket Describe* buffer.

The intent is to give a quick reminder or introduction to something, regardless of whether it has installed documentation -- and to do so within Emacs, without switching to a web browser.

This buffer is also displayed when you use company-mode and press F1 or C-h in its pop up completion list.

  • If the identifier has installed Racket documentation, then a simplified version of the HTML is presented in the buffer, including the "blue box", documentation prose, and examples.

  • Otherwise, if the identifier is a function, then its signature is displayed, for example (name arg-1-name arg-2-name). If it has a contract or a Typed Racket type, that is also displayed.

You can quit the buffer by pressing q. Also, at the bottom of the buffer are Emacs buttons -- which you may navigate among using TAB, and activate using RET -- for racket-visit-definition and racket-doc.


C-c C-d

View documentation of the identifier or string at point.

Uses the default external web browser.

If point is an identifier required in the current namespace that has help, opens the web browser directly at that help topic. (i.e. Uses the identifier variant of racket/help.)

Otherwise, opens the 'search for a term' page, where you can choose among multiple possibilities. (i.e. Uses the string variant of racket/help.)

With a C-u prefix, prompts for the identifier or quoted string, instead of looking at point.



C-c C-f

Fold (hide) all test submodules.


C-c C-u

Unfold (show) all test submodules.


M-x racket-tidy-requires

Make a single top-level require, modules sorted, one per line.

All top-level require forms are combined into a single form. Within that form:

  • A single subform is used for each phase level, sorted in this order: for-syntax, for-template, for-label, for-meta, and plain (phase 0).

    • Within each level subform, the modules are sorted:

      • Collection path modules -- sorted alphabetically.

      • Subforms such as only-in.

      • Quoted relative requires -- sorted alphabetically.

At most one module is listed per line.

Note: This only works for requires at the top level of a source file using #lang. It does not work for requires inside module forms.

See also: racket-trim-requires and racket-base-requires.


M-x racket-trim-requires

Like racket-tidy-requires but also deletes unnecessary requires.

Note: This only works when the source file can be evaluated with no errors.

Note: This only works for requires at the top level of a source file using #lang. It does not work for requires inside module forms. Furthermore, it is not smart about module+ or module* forms -- it may delete top level requires that are actually needed by such submodules.

See also: racket-base-requires.


M-x racket-base-requires

Change from #lang racket to #lang racket/base.

Adds explicit requires for modules that are provided by racket but not by racket/base.

This is a recommended optimization for Racket applications. Avoiding loading all of racket can reduce load time and memory footprint.

Also, as does racket-trim-requires, this removes unneeded modules and tidies everything into a single, sorted require form.

Note: This only works when the source file can be evaluated with no errors.

Note: This only works for requires at the top level of a source file using #lang. It does not work for requires inside module forms. Furthermore, it is not smart about module+ or module* forms -- it may delete top level requires that are actually needed by such submodules.

Note: Currently this only helps change #lang racket to #lang racket/base. It does not help with other similar conversions, such as changing #lang typed/racket to #lang typed/racket/base.


M-x racket-indent-line

Indent current line as Racket code.

This behaves like lisp-indent-line, except that whole-line comments are treated the same regardless of whether they start with single or double semicolons.

  • Automatically indents forms that start with begin in the usual way that begin is indented.

  • Automatically indents forms that start with def or with- in the usual way that define is indented.

  • Has rules for many specific standard Racket forms.

To extend, use your Emacs init file to

(put SYMBOL 'racket-indent-function INDENT)

where SYMBOL is the name of the Racket form (e.g. 'test-case) and INDENT is an integer or the symbol 'defun. When INDENT is an integer, the meaning is the same as for lisp-indent-function and scheme-indent-function: Indent the first n arguments specially and then indent any further arguments like a body.

For example in your .emacs file you could use:

(put 'test-case 'racket-indent-function 1)

to change the indent of test-case from this:

(test-case foo

to this:

(test-case foo

If racket-indent-function has no property for a symbol, scheme-indent-function is also considered (although the with-x indents defined by scheme-mode are ignored). This is only to help people who may have extensive scheme-indent-function settings, particularly in the form of file or dir local variables. Otherwise prefer racket-indent-function.



Automatically insert a ( or a [ as appropriate.

When racket-smart-open-bracket-enable is nil, this simply inserts [. Otherwise, this behaves like the "Automatically adjust opening square brackets" feature in Dr. Racket:

By default, inserts a (. Inserts a [ in the following cases:

  • let-like bindings -- forms with let in the name as well as things like parameterize, with-handlers, and with-syntax.

  • case, cond, match, syntax-case, syntax-parse, and syntax-rules clauses.

  • for-like bindings and for/fold accumulators.

  • class declaration syntax, such as init and inherit.

When the previous s-expression in a sequence is a compound expression, uses the same kind of delimiter.

To force insert [, use quoted-insert: C-q [.

Combined with racket-insert-closing this means that you can press the unshifted [ and ] keys to get whatever delimiters follow the Racket conventions for these forms. (When electric-pair-mode or paredit-mode is active, you need not even press ].


C-c C-p

Cycle the sexpr among () [] {}.



Like backward-up-list but works when point is in a string or comment.

Typically you should not use this command in Emacs Lisp -- especially not repeatedly. Instead, initially use racket--escape-string-or-comment to move to the start of a string or comment, if any, then use normal backward-up-list repeatedly.


M-x racket-check-syntax-mode

Analyze the buffer and annotate with information.

The buffer becomes read-only until you exit this minor mode. However you may navigate the usual ways. When point is on a definition or use, related items are highlighted and information is displayed in the echo area. You may also use special commands to navigate among the definition and its uses.

key             binding
---             -------

TAB		racket-check-syntax-mode-goto-next-def
.		racket-check-syntax-mode-goto-def
h		racket-check-syntax-mode-help
j		racket-check-syntax-mode-goto-next-def
k		racket-check-syntax-mode-goto-prev-def
n		racket-check-syntax-mode-goto-next-use
p		racket-check-syntax-mode-goto-prev-use
q		racket-check-syntax-mode-quit
r		racket-check-syntax-mode-rename
<backtab>	racket-check-syntax-mode-goto-prev-def


M-x racket-unicode-input-method-enable

Set input method to racket-unicode.

The racket-unicode input method lets you easily type various Unicode symbols that might be useful when writing Racket code.

To automatically enable the racket-unicode input method in racket-mode buffers use M-x customize-variable <RET> racket-mode-hook or put the following code in your Emacs init file:

(add-hook 'racket-mode-hook #'racket-unicode-input-method-enable)

Likewise for racket-repl-mode buffers:

(add-hook 'racket-repl-mode-hook #'racket-unicode-input-method-enable)

To temporarily enable this input method for a single buffer you can use M-x racket-unicode-input-method-enable.

Use C-\ to toggle the input method.

When the racket-unicode input method is active, you can for example type All and it is immediately replaced with . A few other examples:

omega     ω
x_1       x₁
x^1       x¹
|A|       𝔸
test-->>E test-->>∃ (racket/redex)

To see a table of all key sequences use M-x describe-input-method <RET> racket-unicode.

If you don’t like the highlighting of partially matching tokens you can turn it off by setting input-method-highlight-flag to nil via M-x customize-variable.


M-x racket-align

Align values in the same column.

Useful for binding forms like let and parameterize, conditionals like cond and match, association lists, and any series of couples like the arguments to hash.

Before choosing this command, put point on the first of a series of "couples". A couple is:

  • A list of two or more sexprs: [sexpr val sexpr ...]
  • Two sexprs: sexpr val.

Each val moves to the same column and is prog-indent-sexp-ed (in case it is a multi-line form).

For example with point on the [ before a:

Before             After

(let ([a 12]       (let ([a   12]
      [bar 23])          [bar 23])
  ....)              ....)

'([a . 12]         '([a   . 12]
  [bar . 23])        [bar . 23])

(cond [a? #t]      (cond [a?   #t]
      [b? (f x           [b?   (f x
             y)]                  y)]
      [else #f])         [else #f])

Or with point on the ' before a:

(list 'a 12        (list 'a   12
      'bar 23)           'bar 23)

If more than one couple is on the same line, none are aligned, because it is unclear where the value column should be. For example the following form will not change; racket-align will display an error message:

(let ([a 0][b 1]
      [c 2])       error; unchanged

When a couple's sexprs start on different lines, that couple is ignored. Other, single-line couples in the series are aligned as usual. For example:

(let ([foo         (let ([foo
       0]                 0]
      [bar 1]            [bar 1]
      [x 2])             [x   2])
  ....)              ....)

See also: racket-unalign.


M-x racket-unalign

The opposite of racket-align.

Effectively does M-x just-one-space and prog-indent-sexp for each couple's value.


Default value for the variable completion-at-point-functions.

Completion candidates are drawn from the namespace symbols resulting from the most recent racket-run of each .rkt file. If a file has never been run, candidates default to values also used for font-lock -- an assortment of symbols from common Racket modules such as racket, typed/racket, and syntax/parse.

Returns extra :company-doc-buffer and :company-location properties for use by the company-mode backend company-capf -- but not :company-docsig, because it is frequently impossible to supply this quickly enough or at all.

Macro expand


M-x racket-stepper-mode

Major mode for Racket stepper output.

Used by the commands racket-expand-file, racket-expand-definition, racket-expand-region, and racket-expand-last-sexp.

key             binding
---             -------

RET		racket-stepper-step
j		racket-stepper-next-item
k		racket-stepper-previous-item
n		racket-stepper-next-item
p		racket-stepper-previous-item

In addition to any hooks its parent mode special-mode might have run, this mode runs the hook racket-stepper-mode-hook, as the final or penultimate step during initialization.


C-c C-e f

Expand the racket-mode buffer's file in racket-stepper-mode.

Uses the macro-debugger package to do the expansion.

You do not need to racket-run the file first; the namespace active in the REPL is not used.

If the file is non-trivial and/or is not compiled to a .zo bytecode file, then it might take many seconds before the original form is displayed and you can start stepping.

With a prefix, also expands syntax from racket/base -- which can result in very many expansion steps.


C-c C-e r

Expand the active region using racket-stepper-mode.

Uses Racket's expand-once in the namespace from the most recent racket-run.


C-c C-e x

Expand the definition around point using racket-stepper-mode.

Uses Racket's expand-once in the namespace from the most recent racket-run.


C-c C-e e

Expand the sexp before point using racket-stepper-mode.

Uses Racket's expand-once in the namespace from the most recent racket-run.



M-x racket-mode-start-faster

Compile racket-mode's .rkt files for faster startup.

racket-mode is implemented as an Emacs Lisp "front end" that talks to a Racket process "back end". Because racket-mode is delivered as an Emacs package instead of a Racket package, installing it does not do the raco setup that is normally done for Racket packages.

This command will do a raco make of racket-mode's .rkt files, creating bytecode files in a compiled/ subdirectory. As a result, when a racket-run or racket-repl command must start the Racket process, it will start faster.

If you run this command, ever, you should run it again after:

  • Installing an updated version of racket-mode. Otherwise, you might lose some of the speed-up.

  • Installing a new version of Racket and/or changing the value of the variable racket-program. Otherwise, you might get an error message due to the bytecode being different versions.


Note: You may also set these via Customize.



Pathname of the racket executable.


Port number for Racket REPL command server.


Timeout for Racket REPL command server.


Terminate the Racket process if memory use exceeds this value in MB. Changes to this value take effect upon the next racket-run. A value of 0 means no limit.

Caveat: This uses Racket's custodian-limit-memory, which does not enforce the limit exactly. Instead, the program will be terminated upon the first garbage collection where memory exceeds the limit (maybe by a significant amount).


The level of context used for racket-run error stack traces.

Each level improves stack trace information, but causes your program to run more slowly.

  • 'low corresponds to compile-context-preservation-enabled #f.

  • 'medium corresponds to compile-context-preservation-enabled #t, which disables some optimizations like inlining.

  • 'high corresponds to compile-context-preservation-enabled #t and to use of errortrace, which heavily instruments your code and therefore may be significantly slower.

Tip: Regardless of this setting, you can enable 'high errortrace for a specific racket-run using a C-u prefix. This lets you normally run with a faster setting, and temporarily re-run to get a more-helpful error message.


List of command-line arguments to supply to your Racket program.

Accessible in your Racket program in the usual way -- the parameter current-command-line-arguments and friends.

This is an Emacs buffer-local variable -- convenient to set as a file local variable. For example at the end of your .rkt file:

;; Local Variables:
;; racket-user-command-line-arguments: ("-f" "bar")
;; End:

Set this way the value must be an unquoted list of strings such as:

("-f" "bar")

but NOT:

'("-f" "bar")
(list "-f" "bar")



Input matching this regexp are not saved on the history list. Defaults to a regexp ignoring all inputs of 0, 1, or 2 letters.


Whether to display inline images in the REPL.


How many images to keep in the image cache.


Which system image viewer program to invoke upon M-x racket-view-last-image.


Use pretty-print instead of print in REPL.



Indent {} with items aligned with the head item? This is indirectly disabled if racket-indent-sequence-depth is 0. This is safe to set as a file-local variable.


To what depth should racket-indent-line search. This affects the indentation of forms like '()` `() #() -- and {} if racket-indent-curly-as-sequence is t -- but not #'() #`() ,() ,@(). A zero value disables, giving the normal indent behavior of DrRacket or Emacs lisp-mode derived modes like scheme-mode. Setting this to a high value can make indentation noticeably slower. This is safe to set as a file-local variable.


Display lambda keywords using λ. This is DEPRECATED. Instead use prettify-symbols-mode in newer verisons of Emacs, or, use racket-insert-lambda to insert actual λ characters.


Use racket-smart-open-bracket when [ is pressed?


Configuration of racket-logger-mode topics and levels

The topic '* respresents the default level used for topics not assigned a level. Otherwise, the topic symbols are the same as used by Racket's define-logger.

The levels are those used by Racket's logging system: 'debug, 'info, 'warning, 'error, 'fatal.

For more information see:

The default value sets some known "noisy" topics to be one level quieter. That way you can set the '* topic to a level like 'debug and not get overhwelmed by these noisy topics.

Experimental debugger


Used to tell racket-run what files may be instrumented for debugging. Must be a list of strings that are pathnames, such as from racket--buffer-file-name, -or-, a function that returns such a list given the pathname of the file being run. If any path strings are relative, they are made absolute using expand-file-name with the directory of the file being run. The symbol 'run-file may be supplied in the list; it will be replaced with the pathname of the file being run. Safe to set as a file-local variable.


Note: You may also set these via Customize.


Face for #:keyword arguments.


Face for self-evaluating expressions like numbers, symbols, strings.


Face for here strings.


Face racket-check-syntax uses to highlight definitions.


Face racket-check-syntax uses to highlight uses.


Face for racket-logger-mode configuration.


Face for racket-logger-mode topics.


Face for racket-logger-mode fatal level.


Face for racket-logger-mode error level.


Face for racket-logger-mode warning level.


Face for racket-logger-mode info level.


Face for racket-logger-mode debug level.