path: root/doc/ale.txt

*ale.txt*  For Vim version 8.0.  Last change: 2016 October 10
*ale*

ALE - Asynchronous Lint Engine

===============================================================================
CONTENTS                                                         *ale-contents*

  1. Introduction...............................|ale-introduction|
  2. Supported Languages & Tools................|ale-support|
  3. Global Options.............................|ale-options|
  4. Linter Specific Options....................|ale-linter-options|
    4.1.  eslint................................|ale-linter-options-eslint|
    4.2.  jshint................................|ale-linter-options-jshint|
    4.3.  phpcs.................................|ale-linter-options-phpcs|
    4.4.  html-tidy.............................|ale-linter-options-html-tidy|
    4.5.  c-gcc.................................|ale-linter-options-c-gcc|
    4.6.  cpp-gcc...............................|ale-linter-options-cpp-gcc|
    4.7.  fortran-gcc...........................|ale-linter-options-fortran-gcc|
    4.8.  shell.................................|ale-linter-options-shell|
    4.9.  shellcheck............................|ale-linter-options-shellcheck|
    4.10. vint..................................|ale-linter-options-vint|
    4.11. luacheck..............................|ale-linter-options-luacheck|
    4.12. c-cppcheck............................|ale-linter-options-c-cppcheck|
    4.13. cpp-cppcheck..........................|ale-linter-options-cpp-cppcheck|
  5. API........................................|ale-api|
  6. Special Thanks.............................|ale-special-thanks|
  7. Contact....................................|ale-contact|

===============================================================================
1. Introduction                                              *ale-introduction*

ALE provides the means to run linters asynchronously in Vim in a variety of
languages and tools. ALE sends the contents of buffers to linter programs
using the |job-control| features available in Vim 8 and NeoVim. For Vim 8,
Vim must be compiled with the |job| and |channel| and |timer| features
as a minimum.

ALE supports the following key features:

1. Running linters when text is changed.
2. Running linters when files are opened.
3. Running linters when files are saved. (When a global flag is set.)
4. Populating the |loclist| with warning and errors.
5. Setting |signs| with warnings and errors for error markers.
6. Using |echo| to show error messages when the cursor moves.

===============================================================================
2. Supported Languages & Tools                                    *ale-support*

The following languages and tools are supported.

* Ansible: 'ansible-lint'
* Bash: 'shell' (-n flag), 'shellcheck'
* Bourne Shell: 'shell' (-n flag), 'shellcheck'
* C: 'cppcheck', 'gcc'
* C++ (filetype cpp): 'cppcheck', 'gcc'
* CoffeeScript: 'coffee', 'coffelint'
* CSS: 'csslint'
* Cython (pyrex filetype): 'cython'
* D: 'dmd'
* Elixir: 'credo'
* Fortran: 'gcc'
* Go: 'gofmt -e', 'go vet', 'golint'
* Haskell: 'ghc', 'hlint'
* HTML: 'HTMLHint', 'tidy'
* JavaScript: 'eslint', 'jscs', 'jshint'
* JSON: 'jsonlint'
* Lua: 'luacheck'
* Perl: 'perl' (-c flag), 'perlcritic'
* PHP: 'php' (-l flag), 'phpcs'
* Pug: 'pug-lint'
* Python: 'flake8'
* Ruby: 'rubocop'
* SASS: 'sasslint'
* SCSS: 'sasslint', 'scsslint'
* Scala: 'scalac'
* TypeScript: 'tslint'
* Verilog: 'iverilog', 'verilator'
* Vim: 'vint'
* YAML: 'yamllint'

===============================================================================
3. Global Options                                                 *ale-options*

g:ale_linters                                                   *g:ale_linters*

  Type: |Dictionary|
  Default: `{}`

  The |g:ale_linters| option sets a |Dictionary| mapping a filetype
  to a |List| of linter programs to be run when checking particular filetypes.
  Only the filetypes specified in the dictionary will be limited in terms
  of which linters will be run.

  This |Dictionary| will be merged with a default dictionary containing the
  following values: >

  {
  \   'zsh': ['shell'],
  \   'csh': ['shell'],
  \}
<
  This option can be used to enable only a particular set of linters for a
  file. For example, you can enable only 'eslint' for JavaScript files: >

  let g:ale_linters = {'javascript': ['eslint']}
<
  If you want to disable all linters for a particular filetype, you can pass
  an empty list of linters as the value: >

  let g:ale_linters = {'javascript': []}
<
  All linters available for a given filetype can be enabled by using the
  string `'all'`: >

  let g:ale_linters = {'c': 'all'}
<

g:ale_linter_aliases                                     *g:ale_linter_aliases*

  Type: |Dictionary|
  Default: `{}`

  The |g:ale_linter_aliases| option can be used to set aliases from one
  filetype to another. A given filetype can be mapped to use the linters
  run for another given filetype.

  This |Dictionary| will be merged with a default dictionary containing the
  following values: >

  {
  \   'zsh': 'sh',
  \   'csh': 'sh',
  \}
<
  For example, if you wish to map a new filetype `'foobar'` to run the `'php'`
  linters, you could set the following: >

  let g:ale_linter_aliases = {'foobar': 'php'}
<
  When combined with the |g:ale_linters| option, the original filetype
  (`'foobar'`) will be used for determining which linters to run,
  not the aliased type (`'php'`). This allows an aliased type to run a
  different set of linters from the type it is being mapped to.


g:ale_lint_on_text_changed                         *g:ale_lint_on_text_changed*

  Type: |Number|
  Default: `1`

  By default, ALE will check files with the various supported programs when
  text is changed by using the |TextChanged| event. If this behaviour is not
  desired, then this option can be disabled by setting it to 0. The
  |g:ale_lint_delay| variable will be used to set a |timer_start()| on a
  delay, and each change to a file will continue to call |timer_stop()| and
  |timer_start()| repeatedly until the timer ticks by, and the linters will be
  run. The checking of files will run in the background, so it should not
  inhibit editing files.


g:ale_lint_delay                                             *g:ale_lint_delay*

  Type: |Number|
  Default: `200`

  This variable controls the milliseconds delay after which the linters will
  be run after text is changed. This option is only meaningful with the
  |g:ale_lint_on_text_changed| variable set to `1`.


g:ale_lint_on_enter                                       *g:ale_lint_on_enter*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, the |BufEnter| and |BufRead| events will be
  used to apply linters when buffers are first opened. If this is not desired,
  this variable can be set to `0` in your vimrc file to disable this
  behaviour.


g:ale_lint_on_save                                         *g:ale_lint_on_save*

  Type: |Number|
  Default: `0`

  This option will make ALE run the linters whenever a file is saved when it
  it set to `1` in your vimrc file. This option can be used in combination
  with the |g:ale_lint_on_enter| and |g:ale_lint_on_text_changed| options to
  make ALE only check files after that have been saved, if that is what is
  desired.


g:ale_set_loclist                                           *g:ale_set_loclist*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, the |loclist| will be populate with any
  warnings and errors which are found by ALE. This feature can be used to
  implement jumping between errors through typical use of |lnext| and |lprev|.


g:ale_set_signs                                               *g:ale_set_signs*

  Type: |Number|
  Default: `has('signs')`

  When this option is set to `1`, the |sign| column will be populated with
  signs marking where errors and warnings appear in the file. The
  `ALEErrorSign` and `ALEWarningSign` highlight groups will be used to provide
  highlighting for the signs. The text used for signs can be customised with
  the |g:ale_sign_error| and |g:ale_sign_warning| options.


g:ale_sign_column_always                             *g:ale_sign_column_always*

  Type: |Number|
  Default: `0`

  By default, the sign gutter will disappear when all warnings and errors have
  been fixed for a file. When this option is set to `1`, the sign column will
  remain open. This can be preferable if you don't want the text in your file
  to move around as you edit a file.


g:ale_sign_error                                             *g:ale_sign_error*

  Type: |String|
  Default: `'>>'`

  This string can be changed to change the characters used for the sign gutter
  for lines which at least one error on them. Lines with both errors and
  warnings on them will show the error marker, as errors take precedence.


g:ale_sign_warning                                         *g:ale_sign_warning*

  Type: |String|
  Default: `'--'`

  This string can be changed to change the characters used for the sign gutter
  for lines which at least one warning on them.


g:ale_sign_offset                                           *g:ale_sign_offset*

  Type: |Number|
  Default: `1000000`

  This variable controls offset from which numeric IDs will be generated for
  new signs. Signs cannot share the same ID values, so when two Vim plugins
  set signs at the same time, the IDs have to be configured such that they do
  not conflict with one another. If the IDs used by ALE are found to conflict
  with some other plugin, this offset value can be changed, and hopefully both
  plugins will work together. See |sign-place| for more information on how
  signs are set.


g:ale_echo_cursor                                           *g:ale_echo_cursor*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, a truncated message will be echoed when a
  cursor is near a warning or error. ALE will attempt to find the warning or
  error at a column nearest to the cursor when the cursor is resting on a line
  which contains a warning or error. This option can be set to `0` to disable
  this behaviour.
  The format of the message can be customizable in |g:ale_echo_msg_format|.


g:ale_echo_msg_format                                    *g:ale_echo_msg_format*

  Type: |String|
  Default: `%s`

  This variable defines the format of the echoed message. The `%s` is the
  error message itself, and it can contain the following handlers:
  - `%linter%` for linter's name
  - `%severity%` for the type of severity
  Note |`g:ale_echo_cursor`| should be setted to 1


g:ale_echo_msg_error_str                              *g:ale_echo_msg_error_str*

  Type: |String|
  Default: `Error`

  The string used for error severity in the echoed message.
  Note |`g:ale_echo_cursor`| should be set to 1
  Note |`g:ale_echo_msg_format`| should contain the `%severity%` handler


g:ale_echo_msg_warning_str                          *g:ale_echo_msg_warning_str*

  Type: |String|
  Default: `Warning`

  The string used for warning severity in the echoed message.
  Note |`g:ale_echo_cursor`| should be set to 1
  Note |`g:ale_echo_msg_format`| should contain the `%severity%` handler


g:ale_warn_about_trailing_whitespace     *g:ale_warn_about_trailing_whitespace*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, warnings relating to trailing whitespace on
  lines will be shown in signs, the loclist, and echo messages, etc. If these
  errors are found to be too irritating while edits are being made, and you
  have configured Vim to automatically remove trailing whitespace, then you
  can disable these warnings for some linters by setting this option to `0`.

  Not all linters may respect this option. If a linter does not, please file a
  bug report, and it may be possible to add such support.


g:ale_statusline_format                               *g:ale_statusline_format*

  Type: |List|
  Default: `['%d error(s)', '%d warning(s)', 'OK']`

  This variable defines the format of |`ale#statusline#status()`| output.
  - The 1st element is for errors
  - The 2nd element is for warnings
  - The 3rd element is for when no errors are detected

g:airline#extensions#ale#enabled             *g:airline#extensions#ale#enabled*

  Type: |Number|
  Default: `1`

  Enables or disables the |airline|'s native extension for ale, which displays
  warnings and errors in the status line, prefixed by
  |airline#extensions#ale#error_symbol| and
  |airline#extensions#ale#warning_symbol|.

===============================================================================
4. Linter Specific Options                                 *ale-linter-options*

Some linters have specific options which can be configured for each of them,
for customising their behaviour.

-------------------------------------------------------------------------------
4.1. eslint                                         *ale-linter-options-eslint*

g:ale_javascript_eslint_executable         *g:ale_javascript_eslint_executable*

  Type: |String|
  Default: `'eslint'`

  ALE will first discover the eslint path in an ancestor node_modules
  directory. If no such path exists, this variable will be used instead.

  This variable can be set to change the path to eslint. If you have eslint_d
  installed, you can set this option to use eslint_d instead.

  If you wish to use only a globally installed version of eslint, set
  |g:ale_javascript_eslint_use_global| to `1`.


g:ale_javascript_eslint_use_global         *g:ale_javascript_eslint_use_global*

  Type: |String|
  Default: `0`

  This variable controls whether or not ALE will search for a local path for
  eslint first. If this variable is set to `1`, then ALE will always use the
  global version of eslint, in preference to locally installed versions of
  eslint in node_modules.


-------------------------------------------------------------------------------
4.2. jshint                                         *ale-linter-options-jshint*

g:ale_javascript_jshint_executable         *g:ale_javascript_jshint_executable*

  Type: |String|
  Default: `'jshint'`

  This variable can be changed to change the path to jshint.


-------------------------------------------------------------------------------
4.3. phpcs                                           *ale-linter-options-phpcs*

g:ale_php_phpcs_standard                             *g:ale_php_phpcs_standard*

  Type: |String|
  Default: `''`

  This variable can be set to specify the coding standard used by phpcs. If no
  coding standard is specified, phpcs will default to checking against the
  PEAR coding standard, or the standard you have set as the default.


-------------------------------------------------------------------------------
4.4. html-tidy                                   *ale-linter-options-html-tidy*

g:ale_html_tidy_executable                         *g:ale_html_tidy_executable*

  Type: |String|
  Default: `'tidy'`

  This variable can be changed to change the path to tidy.


g:ale_html_tidy_args                                     *g:ale_html_tidy_args*

  Type: |String|
  Default: `'-q -e -language en'`

  This variable can be changed to change the arguments provided to the
  executable.

  ALE will attempt to automatically detect the appropriate file encoding to
  provide to html-tidy, and fall back to UTF-8 when encoding detection fails.

  The recognized file encodings are as follows: ascii, big5, cp1252 (win1252),
  cp850 (ibm858), cp932 (shiftjis), iso-2022-jp (iso-2022), latin1, macroman
  (mac), sjis (shiftjis), utf-16le, utf-16, utf-8


-------------------------------------------------------------------------------
4.5. c-gcc                                           *ale-linter-options-c-gcc*

g:ale_c_gcc_options                                       *g:ale_c_gcc_options*

  Type: |String|
  Default: `'-std=c11 -Wall'`

  This variable can be change to modify flags given to gcc.


-------------------------------------------------------------------------------
4.6. cpp-gcc                                       *ale-linter-options-cpp-gcc*

g:ale_cpp_gcc_options                                   *g:ale_cpp_gcc_options*

  Type: |String|
  Default: `'-std=c++14 -Wall'`

  This variable can be changed to modify flags given to gcc.


-------------------------------------------------------------------------------
4.7. fortran-gcc                               *ale-linter-options-fortran-gcc*

g:ale_fortran_gcc_options                           *g:ale_fortran_gcc_options*

  Type: |String|
  Default: `'-Wall'`

  This variable can be changed to modify flags given to gcc.


-------------------------------------------------------------------------------
4.8. shell                                           *ale-linter-options-shell*

g:ale_linters_sh_shell_default_shell     *g:ale_linters_sh_shell_default_shell*

  Type: |String|
  Default: The current shell (`$SHELL`) or `'bash'` if that cannot be read.

  When ALE runs the linter for shells with the `-n` flag, it will attempt to
  read the shell from the shebang (`#!`) line from the shell script to
  determine the shell program to run. When this detection fails, this variable
  will be used instead.


-------------------------------------------------------------------------------
4.9. shellcheck                                 *ale-linter-options-shellcheck*

g:ale_linters_sh_shellckeck_exclusions *g:ale_linters_sh_shellckeck_exclusions*

  Type: |String|
  Default: `''`

  Set this variable to exclude test(s) for shellcheck (-e/--exclude option).


-------------------------------------------------------------------------------
4.10. vint                                            *ale-linter-options-vint*

g:ale_vim_vint_show_style_issues             *g:ale_vim_vint_show_style_issues*

  Type: |Number|
  Default: `1`

  This variable will enable/disable style issues for Vint. When this option
  is disabled, only warnings and errors which are not purely style issues
  will be reported.


-------------------------------------------------------------------------------
4.11. luacheck                                    *ale-linter-options-luacheck*

g:ale_lua_luacheck_executable                   *g:ale_lua_luacheck_executable*

  Type: |String|
  Default: `'luacheck'`

  This variable can be changed to change the path to luacheck.


-------------------------------------------------------------------------------
4.12. c-cppcheck                                  *ale-linter-options-c-cppcheck*

g:ale_c_cppcheck_options                               *g:ale_c_cppcheck_options*

  Type: |String|
  Default: `'--enable=style'`

  This variable can be changed to modify flags given to cppcheck.


-------------------------------------------------------------------------------
4.13. cpp-cppcheck                              *ale-linter-options-cpp-cppcheck*

g:ale_cpp_cppcheck_options                           *g:ale_cpp_cppcheck_options*

  Type: |String|
  Default: `'--enable=style'`

  This variable can be changed to modify flags given to cppcheck.


===============================================================================
5. API                                                                *ale-api*

ale#Queue(delay)                                                  *ale#Queue()*
  Run linters for the current buffer, based on the filetype of the buffer,
  with a given `delay`. A `delay` of `0` will run the linters immediately.
  The linters will always be run in the background. Calling this function
  again from the same buffer


ale#engine#GetLoclist(buffer)                         *ale#engine#GetLoclist()*

  Given a buffer number, this function will rerurn the list of warnings and
  errors reported by ALE for a given buffer in the format accepted by
  |setqflist()|.


ale#linter#Define(filetype, linter)                       *ale#linter#Define()*
  Given a |String| for a filetype and a |Dictionary| Describing a linter
  configuration, add a linter for the given filetype. The dictionaries each
  offer the following options:

  `name`                   The name of the linter. These names will be used by
                         |g:ale_linters| option for enabling/disabling
                         particular linters.

                         This argument is required.

  `callback`               A |String| or |Funcref| for a callback function
                         accepting two arguments (buffer, lines), for a
                         buffer number the output is for, and the lines of
                         output from a linter.

                         This callback function should return a |List| of
                         |Dictionary| objects in the format accepted by
                         |setqflist()|. The |List| will be sorted by line and
                         then column order so it can be searched with a binary
                         search by in future before being passed on to the
                         |loclist|, etc.

                         This argument is required.

  `executable`             A |String| naming the executable itself which
                         will be run.  This value will be used to check if the
                         program requested is installed or not.

                         Either this or the `executable_callback` argument
                         must be provided.

  `executable_callback  `  A |String| or |Funcref| for a callback function
                         accepting a buffer number. A |String| should be
                         returned for the executable to check. This can be
                         used in place of `executable` when more complicated
                         processing is needed.

  `command`                A |String| for an  executable to run asynchronously.
                         This command will be fed the lines from the buffer to
                         check, and will produce the lines of output given to
                         the `callback`.

                         Either this or the `command_callback` argument must
                         be provided.

  `command_callback`       A |String| or |Funcref| for a callback function
                         accepting a buffer number. A |String| should be
                         returned for a command to run. This can be used in
                         place of `command` when more complicated processing
                         is needed.

  `output_stream`          A |String| for the output stream the lines of output
                         should be read from for the command which is run. The
                         accepted values are `'stdout'`, `'stderr'`, and
                         `'both'`. This argument defaults to `'stdout'`. This
                         argument can be set for linter programs which output
                         their errors and warnings to the stderr stream
                         instead of stdout. The option `'both'` will read
                         from both stder and stdout at the same time.

  Some programs for checking for errors are not capable of receiving input
  from stdin, as is required by ALE. To remedy this, a wrapper script is
  provided named in the variable |g:ale#util#stdin_wrapper|. This variable
  can be called with the regular arguments for any command to forward data
  from stdin to the program, by way of creating a temporary file. The first
  argument to the stdin wrapper must be a file extension to save the temporary
  file with, and the following arguments are the command as normal.
  For example: >
  'command': g:ale#util#stdin_wrapper . ' .hs ghc -fno-code -v0',
<

ale#linter#Get(filetype)                                     *ale#linter#Get()*
  Return all of linters configured for a given filetype as a |List| of
  |Dictionary| values in the format specified by |ale#linter#Define()|.

  Filetypes may be dot-seperated to invoke linters for multiple filetypes:
  for instance, the filetype `javascript.jsx` will return linters for both the
  `javascript` and `jsx` filetype.

  Aliases may be defined in as described in |g:ale_linter_aliases|. Aliases
  are applied after dot-seperated filetypes are broken up into their
  components.


ale#statusline#Status()                               *ale#statusline#Status()*
  Return a formatted string that can be added to the statusline.
  The output's format is defined in |`g:ale_statusline_format`|.
  To enable it, the following should be present in your |statusline| settings: >
  %{ale#statusline#Status()}


g:ale#util#stdin_wrapper                             *g:ale#util#stdin_wrapper*
  This variable names a wrapper script for sending stdin input to programs
  which cannot accept input via stdin. See |ale#linter#Define()| for more.


ALELint                                                               *ALELint*
  This |User| autocommand is triggered by ALE every time it completes a lint
  operation. It can be used to update statuslines, send notifications, or
  complete any other operation that needs to be done after a lint run.
  It can be used simply:
  autocmd User ALELint echom "ALE run!"


===============================================================================
6. Special Thanks                                           *ale-special-thanks*

Special thanks to Mark Grealish (https://www.bhalash.com/) for providing ALE's
snazzy looking ale glass logo. Cheers, Mark!

===============================================================================
7. Contact                                                        *ale-contact*

If you like this plugin, and wish to get in touch, check out the GitHub
page for issues and more at https://github.com/w0rp/ale

If you wish to contact the author of this plugin directly, please feel
free to send an email to devw0rp@gmail.com.


Please drink responsibly, or not at all, which is ironically the preference
of w0rp, who is teetotal.



  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl: