GNU-devel ELPA - expand-region


Increase selected region by semantic units.
expand-region-, 2021-Oct-09, 220 KiB
Magnar Sveen <>
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To install this package, run in Emacs:

M-x package-install RET expand-region RET

Full description

Expand region increases the selected region by semantic units. Just keep
pressing the key until it selects what you want.

An example:

    (setq alphabet-start "abc def")

With the cursor at the `c`, it starts by marking the entire word `abc`, then
expand to the contents of the quotes `abc def`, then to the entire quote
`"abc def"`, then to the contents of the sexp `setq alphabet-start "abc def"`
and finally to the entire sexp.

You can set it up like this:

    (require 'expand-region)
    (global-set-key (kbd "C-=") 'er/expand-region)

There's also `er/contract-region` if you expand too far.

## Video

You can [watch an intro to expand-region at Emacs Rocks](

## Language support

Expand region works fairly well with most languages, due to the general
nature of the basic expansions:


However, most languages also will benefit from some specially crafted
expansions. For instance, expand-region comes with these extra expansions for


You can add your own expansions to the languages of your choice simply by
creating a function that looks around point to see if it's inside or looking
at the construct you want to mark, and if so - mark it.

There's plenty of examples to look at in these files.

After you make your function, add it to a buffer-local version of
the `er/try-expand-list`.


Let's say you want expand-region to also mark paragraphs and pages in
text-mode. Incidentally Emacs already comes with `mark-paragraph` and
`mark-page`. To add it to the try-list, do this:

    (defun er/add-text-mode-expansions ()
      (make-variable-buffer-local 'er/try-expand-list)
      (setq er/try-expand-list (append

    (er/enable-mode-expansions 'text-mode 'er/add-text-mode-expansions)

Add that to its own file, and require it at the bottom of this one,
where it says "Mode-specific expansions"

**Warning:** Badly written expansions might slow down expand-region
dramatically. Remember to exit quickly before you start traversing
the entire document looking for constructs to mark.

## Contribute

If you make some nice expansions for your favorite mode, it would be
great if you opened a pull-request. The repo is at:

Changes to `expand-region-core` itself must be accompanied by feature tests.
They are written in [Ecukes](, a Cucumber for Emacs.

To fetch the test dependencies:

    $ cd /path/to/expand-region
    $ git submodule init
    $ git submodule update

Run the tests with:

    $ ./util/ecukes/ecukes features

If you want to add feature-tests for your mode-specific expansions as well,
that is utterly excellent.

## Contributors

* [Josh Johnston]( contributed `er/contract-region`
* [Le Wang]( contributed consistent handling of the mark ring, expanding into pairs/quotes just left of the cursor, and general code clean-up.
* [Matt Briggs]( contributed expansions for ruby-mode.
* [Ivan Andrus]( contributed expansions for python-mode, text-mode, LaTeX-mode and nxml-mode.
* [Raimon Grau]( added support for when transient-mark-mode is off.
* [Gleb Peregud]( contributed expansions for erlang-mode.
* [fgeller]( and [edmccard]( contributed better support for python and its multiple modes.
* [François Févotte]( contributed expansions for C and C++.
* [Roland Walker]( added option to copy the contents of the most recent action to a register, and some fixes.
* [Damien Cassou]( added option to continue expanding/contracting with fast keys after initial expand.


Old versions

expand-region- KiB