#+title:    :tools eval
#+subtitle: Run code, run (also, repls)
#+created:  February 20, 2017
#+since:    2.0.0

* Description :unfold:
This modules adds inline code evaluation support to Emacs and a universal
interface for opening and interacting with REPLs.

** Maintainers
/This module has no dedicated maintainers./ [[doom-contrib-maintainer:][Become a maintainer?]]

** Module flags
- +overlay ::
  Enable the use of overlays (near the cursor) to display the result of inline
  code evaluation (rather than the minibuffer). If the results are too big the
  minibuffer will be used anyway.

** Packages
- [[doom-package:quickrun]]

** Hacks
- Quickrun has been modified to:
  - Use only one output window, in case of consecutive execution of code.
  - The quickrun window will resize itself to fit its output, once the
    underlying process is finished executing the code.

** TODO Changelog
# This section will be machine generated. Don't edit it by hand.
/This module does not have a changelog yet./

* Installation
[[id:01cffea4-3329-45e2-a892-95a384ab2338][Enable this module in your ~doom!~ block.]]

This module has no direct prerequisites.

However, many languages will require that you install their interpreters, code
runners and/or repls to power the functionality of this module. Visit the
documentation of their respective [[doom-module::lang]] module for instructions.

* TODO Usage
#+begin_quote
 󱌣 /This module's usage documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** Inline Code Evaluation
Quickrun can be invoked via:
- ~M-x +eval/buffer~ (or [[kbd:][gR]], or [[kbd:][M-r]])
- ~M-x +eval/region~
- ~M-x +eval/region-and-replace~
- Evil users can use the [[kbd:][gr]] operator to select and run a region.

** REPLs
Invoked via:
- [[kbd:][SPC o r]] or ~:repl~ will open a REPL in a popup window. [[kbd:][SPC o R]] or ~:repl!~
  will open a REPL in the current window. If a REPL is already open and a
  selection is active, it will be sent to the REPL.
- ~M-x +eval/open-repl-other-window~ ([[kbd:][SPC o r]])
- ~M-x +eval/open-repl-same-window~ ([[kbd:][SPC o R]])
- ~M-x +eval/send-region-to-repl~ ([[kbd:][SPC c s]]) while a selection (and REPL) is
  active

* TODO Configuration
#+begin_quote
 󱌣 /This module's configuration documentation is incomplete./ [[doom-contrib-module:][Complete it?]]
#+end_quote

** Register a REPL for a major-mode
REPLs are defined for most languages Doom supports. Check that language module's
README.org to see if it does (and if it requires additional setup).

To use them, you may use ~M-x +eval/open-repl-other-window~, ~M-x
+eval/open-repl-same-window~, ~:repl~ (for evil users) or the default binding:
[[kbd:][SPC o r]]. These will open a REPL in a popup window.

#+begin_quote
You can simply call that mode's REPL command manually. e.g. ~M-x ielm~, but this
will bar you from the benefits of Doom's REPL system (like send-to-repl
functionality).
#+end_quote

Otherwise, you can define your own for a specified major mode:

~(set-repl-handler! MAJOR-MODES FUNCTION)~

=MAJOR-MODES= is a single major mode symbol or a list of them.

=FUNCTION= should return a repl buffer. Any window changes in this function are
ignored, then the REPL is opened in a popup window. E.g.
#+begin_src emacs-lisp
(defun +lua/open-repl ()
  (interactive)
  (lua-start-process "lua" "lua")
  (pop-to-buffer lua-process-buffer))

(set-repl-handler! 'lua-mode #'+lua/open-repl)
#+end_src

** Change how code is evaluated in a major mode
Run regions or entire buffers with [[https://github.com/syohex/emacs-quickrun][Quickrun]]. Output is show in a popup window.

Quickrun includes support for many languages, usually by sending text directly
to interpreters or compilers. However, occasionally, you'll find a language
without support (like [[https://crystal-lang.org/][Crystal]]), or a language with better Emacs integration
(like elisp).

To define a "runner":
#+begin_src emacs-lisp
(set-eval-handler! 'crystal-mode
  '((:command     . "crystal")
    (:exec        . "%c %s")
    (:description . "Run Crystal script")))
#+end_src

A simpler version is simply to use the path to the binary:
#+begin_src emacs-lisp
(set-eval-handler! 'groovy-mode "groovy")
#+end_src

Or if you'd rather run an elisp command:
#+begin_src emacs-lisp
(set-eval-handler! 'emacs-lisp-mode #'+emacs-lisp-eval)
#+end_src

* TODO Troubleshooting
/There are no known problems with this module./ [[doom-report:][Report one?]]

* Frequently asked questions
/This module has no FAQs yet./ [[doom-suggest-faq:][Ask one?]]

* TODO Appendix
#+begin_quote
 󱌣 This module has no appendix yet. [[doom-contrib-module:][Write one?]]
#+end_quote
