*ale.txt*  For Vim version 8.0.
*ale*

ALE - Asynchronous Lint Engine

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

  1. Introduction.........................|ale-introduction|
  2. Supported Languages & Tools..........|ale-support|
  3. Linting..............................|ale-lint|
  4. Fixing Problems......................|ale-fix|
  5. Language Server Protocol Support.....|ale-lsp|
    5.1 Completion........................|ale-completion|
    5.2 Go To Definition..................|ale-go-to-definition|
    5.3 Find References...................|ale-find-references|
  6. Global Options.......................|ale-options|
    6.1 Highlights........................|ale-highlights|
    6.2 Options for write-good Linter.....|ale-write-good-options|
  7. Integration Documentation............|ale-integrations|
    asciidoc..............................|ale-asciidoc-options|
      write-good..........................|ale-asciidoc-write-good|
    asm...................................|ale-asm-options|
      gcc.................................|ale-asm-gcc|
    awk...................................|ale-awk-options|
      gawk................................|ale-awk-gawk|
    c.....................................|ale-c-options|
      clang...............................|ale-c-clang|
      clang-format........................|ale-c-clangformat|
      clangtidy...........................|ale-c-clangtidy|
      cppcheck............................|ale-c-cppcheck|
      flawfinder..........................|ale-c-flawfinder|
      gcc.................................|ale-c-gcc|
    chef..................................|ale-chef-options|
      foodcritic..........................|ale-chef-foodcritic|
    clojure...............................|ale-clojure-options|
      joker...............................|ale-clojure-joker|
    cmake.................................|ale-cmake-options|
      cmakelint...........................|ale-cmake-cmakelint|
    cpp...................................|ale-cpp-options|
      clang...............................|ale-cpp-clang|
      clangcheck..........................|ale-cpp-clangcheck|
      clang-format........................|ale-cpp-clangformat|
      clangtidy...........................|ale-cpp-clangtidy|
      cppcheck............................|ale-cpp-cppcheck|
      cpplint.............................|ale-cpp-cpplint|
      cquery..............................|ale-cpp-cquery|
      flawfinder..........................|ale-cpp-flawfinder|
      gcc.................................|ale-cpp-gcc|
    c#....................................|ale-cs-options|
      mcs.................................|ale-cs-mcs|
      mcsc................................|ale-cs-mcsc|
    css...................................|ale-css-options|
      prettier............................|ale-css-prettier|
      stylelint...........................|ale-css-stylelint|
    cuda..................................|ale-cuda-options|
      nvcc................................|ale-cuda-nvcc|
    dart..................................|ale-dart-options|
      dartanalyzer........................|ale-dart-dartanalyzer|
    dockerfile............................|ale-dockerfile-options|
      hadolint............................|ale-dockerfile-hadolint|
    elixir................................|ale-elixir-options|
      mix.................................|ale-elixir-mix|
      mix_format..........................|ale-elixir-mix-format|
      dialyxir............................|ale-elixir-dialyxir|
    elm...................................|ale-elm-options|
      elm-format..........................|ale-elm-elm-format|
      elm-make............................|ale-elm-elm-make|
    erlang................................|ale-erlang-options|
      erlc................................|ale-erlang-erlc|
      syntaxerl...........................|ale-erlang-syntaxerl|
    eruby.................................|ale-eruby-options|
    fish..................................|ale-fish-options|
    fortran...............................|ale-fortran-options|
      gcc.................................|ale-fortran-gcc|
    fountain..............................|ale-fountain-options|
    fusionscript..........................|ale-fuse-options|
      fusion-lint.........................|ale-fuse-fusionlint|
    git commit............................|ale-gitcommit-options|
      gitlint.............................|ale-gitcommit-gitlint|
    glsl..................................|ale-glsl-options|
      glslang.............................|ale-glsl-glslang|
      glslls..............................|ale-glsl-glslls|
    go....................................|ale-go-options|
      gobuild.............................|ale-go-gobuild|
      gofmt...............................|ale-go-gofmt|
      gometalinter........................|ale-go-gometalinter|
      staticcheck.........................|ale-go-staticcheck|
    graphql...............................|ale-graphql-options|
      eslint..............................|ale-graphql-eslint|
      gqlint..............................|ale-graphql-gqlint|
      prettier............................|ale-graphql-prettier|
    handlebars............................|ale-handlebars-options|
      ember-template-lint.................|ale-handlebars-embertemplatelint|
    haskell...............................|ale-haskell-options|
      brittany............................|ale-haskell-brittany|
      ghc.................................|ale-haskell-ghc|
      hdevtools...........................|ale-haskell-hdevtools|
      hfmt................................|ale-haskell-hfmt|
      stack-build.........................|ale-haskell-stack-build|
    html..................................|ale-html-options|
      htmlhint............................|ale-html-htmlhint|
      tidy................................|ale-html-tidy|
      write-good..........................|ale-html-write-good|
    idris.................................|ale-idris-options|
      idris...............................|ale-idris-idris|
    java..................................|ale-java-options|
      checkstyle..........................|ale-java-checkstyle|
      javac...............................|ale-java-javac|
      google-java-format..................|ale-java-google-java-format|
      pmd.................................|ale-java-pmd|
    javascript............................|ale-javascript-options|
      eslint..............................|ale-javascript-eslint|
      flow................................|ale-javascript-flow|
      importjs............................|ale-javascript-importjs|
      jscs................................|ale-javascript-jscs|
      jshint..............................|ale-javascript-jshint|
      prettier............................|ale-javascript-prettier|
      prettier-eslint.....................|ale-javascript-prettier-eslint|
      prettier-standard...................|ale-javascript-prettier-standard|
      standard............................|ale-javascript-standard|
      xo..................................|ale-javascript-xo|
    json..................................|ale-json-options|
      fixjson.............................|ale-json-fixjson|
      jsonlint............................|ale-json-jsonlint|
      jq..................................|ale-json-jq|
      prettier............................|ale-json-prettier|
    kotlin................................|ale-kotlin-options|
      kotlinc.............................|ale-kotlin-kotlinc|
      ktlint..............................|ale-kotlin-ktlint|
    latex.................................|ale-latex-options|
      write-good..........................|ale-latex-write-good|
    less..................................|ale-less-options|
      lessc...............................|ale-less-lessc|
      prettier............................|ale-less-prettier|
      stylelint...........................|ale-less-stylelint|
    llvm..................................|ale-llvm-options|
      llc.................................|ale-llvm-llc|
    lua...................................|ale-lua-options|
      luac................................|ale-lua-luac|
      luacheck............................|ale-lua-luacheck|
    markdown..............................|ale-markdown-options|
      mdl.................................|ale-markdown-mdl|
      prettier............................|ale-markdown-prettier|
      textlint............................|ale-markdown-textlint|
      write-good..........................|ale-markdown-write-good|
    mercury...............................|ale-mercury-options|
      mmc.................................|ale-mercury-mmc|
    nasm..................................|ale-nasm-options|
      nasm................................|ale-nasm-nasm|
    nroff.................................|ale-nroff-options|
      write-good..........................|ale-nroff-write-good|
    objc..................................|ale-objc-options|
      clang...............................|ale-objc-clang|
    objcpp................................|ale-objcpp-options|
      clang...............................|ale-objcpp-clang|
    ocaml.................................|ale-ocaml-options|
      merlin..............................|ale-ocaml-merlin|
      ols.................................|ale-ocaml-ols|
    perl..................................|ale-perl-options|
      perl................................|ale-perl-perl|
      perlcritic..........................|ale-perl-perlcritic|
      perltidy............................|ale-perl-perltidy|
    php...................................|ale-php-options|
      hack................................|ale-php-hack|
      hackfmt.............................|ale-php-hackfmt|
      langserver..........................|ale-php-langserver|
      phan................................|ale-php-phan|
      phpcbf..............................|ale-php-phpcbf|
      phpcs...............................|ale-php-phpcs|
      phpmd...............................|ale-php-phpmd|
      phpstan.............................|ale-php-phpstan|
      php-cs-fixer........................|ale-php-php-cs-fixer|
    po....................................|ale-po-options|
      write-good..........................|ale-po-write-good|
    pod...................................|ale-pod-options|
      write-good..........................|ale-pod-write-good|
    pony..................................|ale-pony-options|
      ponyc...............................|ale-pony-ponyc|
    proto.................................|ale-proto-options|
      protoc-gen-lint.....................|ale-proto-protoc-gen-lint|
    pug...................................|ale-pug-options|
      puglint.............................|ale-pug-puglint|
    puppet................................|ale-puppet-options|
      puppetlint..........................|ale-puppet-puppetlint|
    python................................|ale-python-options|
      autopep8............................|ale-python-autopep8|
      black...............................|ale-python-black|
      flake8..............................|ale-python-flake8|
      isort...............................|ale-python-isort|
      mypy................................|ale-python-mypy|
      prospector..........................|ale-python-prospector|
      pycodestyle.........................|ale-python-pycodestyle|
      pyflakes............................|ale-python-pyflakes|
      pylint..............................|ale-python-pylint|
      pyls................................|ale-python-pyls|
      yapf................................|ale-python-yapf|
    qml...................................|ale-qml-options|
      qmlfmt..............................|ale-qml-qmlfmt|
    r.....................................|ale-r-options|
      lintr...............................|ale-r-lintr|
    reasonml..............................|ale-reasonml-options|
      merlin..............................|ale-reasonml-merlin|
      ols.................................|ale-reasonml-ols|
      refmt...............................|ale-reasonml-refmt|
    restructuredtext......................|ale-restructuredtext-options|
      write-good..........................|ale-restructuredtext-write-good|
    ruby..................................|ale-ruby-options|
      brakeman............................|ale-ruby-brakeman|
      rails_best_practices................|ale-ruby-rails_best_practices|
      reek................................|ale-ruby-reek|
      rubocop.............................|ale-ruby-rubocop|
      ruby................................|ale-ruby-ruby|
      rufo................................|ale-ruby-rufo|
    rust..................................|ale-rust-options|
      cargo...............................|ale-rust-cargo|
      rls.................................|ale-rust-rls|
      rustc...............................|ale-rust-rustc|
      rustfmt.............................|ale-rust-rustfmt|
    sass..................................|ale-sass-options|
      stylelint...........................|ale-sass-stylelint|
    scala.................................|ale-scala-options|
      scalafmt............................|ale-scala-scalafmt|
      scalastyle..........................|ale-scala-scalastyle|
    scss..................................|ale-scss-options|
      prettier............................|ale-scss-prettier|
      stylelint...........................|ale-scss-stylelint|
    sh....................................|ale-sh-options|
      shell...............................|ale-sh-shell|
      shellcheck..........................|ale-sh-shellcheck|
      shfmt...............................|ale-sh-shfmt|
    sml...................................|ale-sml-options|
      smlnj...............................|ale-sml-smlnj|
    solidity..............................|ale-solidity-options|
      solhint.............................|ale-solidity-solhint|
      solium..............................|ale-solidity-solium|
    spec..................................|ale-spec-options|
      rpmlint.............................|ale-spec-rpmlint|
    stylus................................|ale-stylus-options|
      stylelint...........................|ale-stylus-stylelint|
    tcl...................................|ale-tcl-options|
      nagelfar............................|ale-tcl-nagelfar|
    terraform.............................|ale-terraform-options|
      tflint..............................|ale-terraform-tflint|
    tex...................................|ale-tex-options|
      chktex..............................|ale-tex-chktex|
      lacheck.............................|ale-tex-lacheck|
    texinfo...............................|ale-texinfo-options|
      write-good..........................|ale-texinfo-write-good|
    text..................................|ale-text-options|
      textlint............................|ale-text-textlint|
      write-good..........................|ale-text-write-good|
    thrift................................|ale-thrift-options|
      thrift..............................|ale-thrift-thrift|
    typescript............................|ale-typescript-options|
      eslint..............................|ale-typescript-eslint|
      prettier............................|ale-typescript-prettier|
      tslint..............................|ale-typescript-tslint|
      tsserver............................|ale-typescript-tsserver|
    verilog/systemverilog.................|ale-verilog-options|
      iverilog............................|ale-verilog-iverilog|
      verilator...........................|ale-verilog-verilator|
    vim...................................|ale-vim-options|
      vint................................|ale-vim-vint|
    vim help..............................|ale-vim-help-options|
      write-good..........................|ale-vim-help-write-good|
    vue...................................|ale-vue-options|
      prettier............................|ale-vue-prettier|
    xhtml.................................|ale-xhtml-options|
      write-good..........................|ale-xhtml-write-good|
    xml...................................|ale-xml-options|
      xmllint.............................|ale-xml-xmllint|
    yaml..................................|ale-yaml-options|
      swaglint............................|ale-yaml-swaglint|
      yamllint............................|ale-yaml-yamllint|
  8. Commands/Keybinds....................|ale-commands|
  9. API..................................|ale-api|
  10. Special Thanks......................|ale-special-thanks|
  11. 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 |timers| features
as a minimum.

ALE supports the following key features for linting:

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.
7. Setting syntax highlights for errors.

ALE can fix problems with files with the |ALEFix| command, using the same job
control functionality used for checking for problems. Try using the
|ALEFixSuggest| command for browsing tools that can be used to fix problems
for the current buffer.

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

The following languages and tools are supported.

Notes:

`^` No linters for text or Vim help filetypes are enabled by default.
`!!` These linters check only files on disk. See |ale-lint-file-linters|

* ASM: `gcc`
* Ansible: `ansible-lint`
* API Blueprint: `drafter`
* AsciiDoc: `alex`!!, `proselint`, `redpen`, `write-good`
* Awk: `gawk`
* Bash: `shell` (-n flag), `shellcheck`, `shfmt`
* Bourne Shell: `shell` (-n flag), `shellcheck`, `shfmt`
* C: `cppcheck`, `cpplint`!!, `clang`, `clangtidy`!!, `clang-format`, `flawfinder`, `gcc`
* C++ (filetype cpp): `clang`, `clangcheck`!!, `clangtidy`!!, `clang-format`, `cppcheck`, `cpplint`!!, `cquery`, `flawfinder`, `gcc`
* CUDA: `nvcc`!!
* C#: `mcs`, `mcsc`!!
* Chef: `foodcritic`
* Clojure: `joker`
* CMake: `cmakelint`
* CoffeeScript: `coffee`, `coffeelint`
* Crystal: `crystal`!!
* CSS: `csslint`, `prettier`, `stylelint`
* Cucumber: `cucumber`
* Cython (pyrex filetype): `cython`
* D: `dmd`
* Dafny: `dafny`!!
* Dart: `dartanalyzer`!!, `language_server`
* Dockerfile: `hadolint`
* Elixir: `credo`, `dialyxir`, `dogma`!!
* Elm: `elm-format, elm-make`
* Erb: `erb`, `erubi`, `erubis`
* Erlang: `erlc`, `SyntaxErl`
* Fish: `fish` (-n flag)
* Fortran: `gcc`
* Fountain: `proselint`
* FusionScript: `fusion-lint`
* Git Commit Messages: `gitlint`
* GLSL: glslang, `glslls`
* Go: `gofmt`, `goimports`, `go vet`!!, `golint`, `gotype`!!, `gometalinter`!!, `go build`!!, `gosimple`!!, `staticcheck`!!
* GraphQL: `eslint`, `gqlint`, `prettier`
* Haml: `haml-lint`
* Handlebars: `ember-template-lint`
* Haskell: `brittany`, `ghc`, `stack-ghc`, `stack-build`!!, `ghc-mod`, `stack-ghc-mod`, `hlint`, `hdevtools`, `hfmt`
* HTML: `alex`!!, `HTMLHint`, `proselint`, `tidy`, `write-good`
* Idris: `idris`
* Java: `checkstyle`, `javac`, `google-java-format`, `PMD`
* JavaScript: `eslint`, `flow`, `jscs`, `jshint`, `prettier`, `prettier-eslint`, `prettier-standard`, `standard`, `xo`
* JSON: `fixjson`, `jsonlint`, `jq`, `prettier`
* Kotlin: `kotlinc`, `ktlint`
* LaTeX (tex): `alex`!!, `chktex`, `lacheck`, `proselint`, `redpen`, `vale`, `write-good`
* Less: `lessc`, `prettier`, `stylelint`
* LLVM: `llc`
* Lua: `luac`, `luacheck`
* Mail: `alex`!!, `proselint`, `vale`
* Make: `checkmake`
* Markdown: `alex`!!, `markdownlint`!!, `mdl`, `prettier`, `proselint`, `redpen`, `remark-lint`, `textlint`, `vale`, `write-good`
* MATLAB: `mlint`
* Mercury: `mmc`!!
* NASM: `nasm`!!
* Nim: `nim check`!!
* nix: `nix-instantiate`
* nroff: `alex`!!, `proselint`, `write-good`
* Objective-C: `clang`
* Objective-C++: `clang`
* OCaml: `merlin` (see |ale-ocaml-merlin|), `ols`
* Perl: `perl -c`, `perl-critic`, `perltidy`
* PHP: `hack`, `hackfmt`, `langserver`, `phan`, `php -l`, `phpcs`, `phpmd`, `phpstan`, `phpcbf`, `php-cs-fixer`
* PO: `alex`!!, `msgfmt`, `proselint`, `write-good`
* Pod: `alex`!!, `proselint`, `write-good`
* Pony: `ponyc`
* proto: `protoc-gen-lint`
* Pug: `pug-lint`
* Puppet: `puppet`, `puppet-lint`
* Python: `autopep8`, `black`, `flake8`, `isort`, `mypy`, `prospector`, `pycodestyle`, `pyls`, `pylint`!!, `yapf`
* QML: `qmlfmt`, `qmllint`
* R: `lintr`
* ReasonML: `merlin`, `ols`, `refmt`
* reStructuredText: `alex`!!, `proselint`, `redpen`, `rstcheck`, `vale`, `write-good`
* Re:VIEW: `redpen`
* RPM spec: `rpmlint`
* Ruby: `brakeman`, `rails_best_practices`!!, `reek`, `rubocop`, `ruby`, `rufo`
* Rust: `cargo`!!, `rls`, `rustc` (see |ale-integration-rust|), `rustfmt`
* SASS: `sass-lint`, `stylelint`
* SCSS: `prettier`, `sass-lint`, `scss-lint`, `stylelint`
* Scala: `fsc`, `scalac`, `scalafmt`, `scalastyle`
* Slim: `slim-lint`
* SML: `smlnj`
* Solidity: `solhint`, `solium`
* Stylus: `stylelint`
* SQL: `sqlint`
* Swift: `swiftlint`, `swiftformat`
* Tcl: `nagelfar`!!
* Terraform: `tflint`
* Texinfo: `alex`!!, `proselint`, `write-good`
* Text^: `alex`!!, `proselint`, `redpen`, `textlint`, `vale`, `write-good`
* Thrift: `thrift`
* TypeScript: `eslint`, `prettier`, `tslint`, `tsserver`, `typecheck`
* Verilog: `iverilog`, `verilator`
* Vim: `vint`
* Vim help^: `alex`!!, `proselint`, `write-good`
* Vue: `prettier`
* XHTML: `alex`!!, `proselint`, `write-good`
* XML: `xmllint`
* YAML: `swaglint`, `yamllint`

===============================================================================
3. Linting                                                           *ale-lint*

ALE's primary focus is on checking for problems with your code with various
programs via some Vim code for integrating with those programs, referred to
as 'linters.' ALE supports a wide array of programs for linting by default,
but additional programs can be added easily by defining files in |runtimepath|
with the filename pattern `ale_linters/<filetype>/<filename>.vim`. For more
information on defining new linters, see the extensive documentation
for |ale#linter#Define()|.

Without any configuration, ALE will attempt to check all of the code for every
file you open in Vim with all available tools by default. To see what ALE
is doing, and what options have been set, try using the |:ALEInfo| command.

Most of the linters ALE runs will check the Vim buffer you are editing instead
of the file on disk. This allows you to check your code for errors before you
have even saved your changes. ALE will check your code in the following
circumstances, which can be configured with the associated options.

* When you modify a buffer.                - |g:ale_lint_on_text_changed|
* When you open a new or modified buffer.  - |g:ale_lint_on_enter|
* When you save a buffer.                  - |g:ale_lint_on_save|
* When the filetype changes for a buffer.  - |g:ale_lint_on_filetype_changed|
* If ALE is used to check code manually.   - |:ALELint|

In addition to the above options, ALE can also check buffers for errors when
you leave insert mode with |g:ale_lint_on_insert_leave|, which is off by
default. It is worth reading the documentation for every option.

                                                        *ale-lint-file-linters*

Some programs must be run against files which have been saved to disk, and
simply do not support reading temporary files or stdin, either of which are
required for ALE to be able to check for errors as you type. The programs
which behave this way are documented in the lists and tables of supported
programs. ALE will only lint files with these programs in the following
circumstances.

* When you open a new or modified buffer.  - |g:ale_lint_on_enter|
* When you save a buffer.                  - |g:ale_lint_on_save|
* When the filetype changes for a buffer.  - |g:ale_lint_on_filetype_changed|
* If ALE is used to check code manually.   - |:ALELint|

ALE will report problems with your code in the following ways, listed with
their relevant options.

* By updating loclist. (On by default)       - |g:ale_set_loclist|
* By updating quickfix. (Off by default)     - |g:ale_set_quickfix|
* By setting error highlights.               - |g:ale_set_highlights|
* By creating signs in the sign column.      - |g:ale_set_signs|
* By echoing messages based on your cursor.  - |g:ale_echo_cursor|
* By showing balloons for your mouse cursor  - |g:ale_set_balloons|

Please consult the documentation for each option, which can reveal some other
ways of tweaking the behaviour of each way of displaying problems. You can
disable or enable whichever options you prefer.

Most settings can be configured for each buffer. (|b:| instead of |g:|),
including disabling ALE for certain buffers with |b:ale_enabled|. The
|g:ale_pattern_options| setting can be used to configure files differently
based on regular expressions for filenames. For configuring entire projects,
the buffer-local options can be used with external plugins for reading Vim
project configuration files. Buffer-local settings can also be used in
ftplugin files for different filetypes.

ALE offers several options for controlling which linters are run.

* Selecting linters to run.            - |g:ale_linters|
* Aliasing filetypes for linters       - |g:ale_linter_aliases|
* Only running linters you asked for.  - |g:ale_linters_explicit|


===============================================================================
4. Fixing Problems                                                    *ale-fix*

ALE can fix problems with files with the |ALEFix| command. |ALEFix|
accepts names of fixers to be applied as arguments. Alternatively,
when no arguments are provided, the variable |g:ale_fixers| will be
read for getting a |List| of commands for filetypes, split on `.`, and
the functions named in |g:ale_fixers| will be executed for fixing the
errors.

The |ALEFixSuggest| command can be used to suggest tools that be used to
fix problems for the current buffer.

The values for `g:ale_fixers` can be a list of |String|, |Funcref|, or
|lambda| values. String values must either name a function, or a short name
for a function set in the ALE fixer registry.

Each function for fixing errors must accept either one argument `(buffer)` or
two arguments `(buffer, lines)`, representing the buffer being fixed and the
lines to fix. The functions must return either `0`, for changing nothing, a
|List| for new lines to set, or a |Dictionary| for describing a command to be
run in the background.

Functions receiving a variable number of arguments will not receive the second
argument `lines`. Functions should name two arguments if the `lines` argument
is desired. This is required to avoid unnecessary copying of the lines of
the buffers being checked.

When a |Dictionary| is returned for an |ALEFix| callback, the following keys
are supported for running the commands.

  `command`             A |String| for the command to run. This key is required.

                      When `%t` is included in a command string, a temporary
                      file will be created, containing the lines from the file
                      after previous adjustment have been done.

  `read_temporary_file` When set to `1`, ALE will read the contents of the
                      temporary file created for `%t`. This option can be used
                      for commands which need to modify some file on disk in
                      order to fix files.

  `process_with`        An optional callback for post-processing.

                      The callback must accept two arguments,
                      `(buffer, output)`, which can be used for converting
                      the output from a command into lines to replace the
                      buffer's contents with.

                      A |List| of |String|s must be returned.

  `chain_with`          An optional key for defining a callback to call next.

                      The callback must accept two or three arguments,
                      `(buffer, output)` or `(buffer, output, input)` .
                      Functions receiving a variable number of arguments will
                      only receive the first two values. The `output` argument
                      will contain the lines of output from the command run.
                      The `input` argument is the List of lines for the
                      buffer, after applying any previous fixers.

                      The callback must return the same values returned for
                      any fixer function. This allows fixer functions to be
                      chained recursively.

                      When the command string returned for a fixer is an empty
                      string, the next command in the chain will still be run.
                      This allows commands to be skipped, like version checks
                      that are cached. An empty List will be passed to the
                      next callback in the chain for the `output`.

  `read_buffer`         An optional key for disabling reading the buffer.

                      When set to `0`, ALE will not pipe the buffer's data
                      into the command via stdin. This option is ignored and
                      the buffer is not read when `read_temporary_file` is
                      `1`.

                      This option defaults to `0` when `chain_with` is defined
                      as anything other than `v:null`, and defaults to `1`
                      otherwise. This is so earlier commands in a chain
                      do not receive the buffer's data by default.

                                                        *ale-fix-configuration*

Synchronous functions and asynchronous jobs will be run in a sequence for
fixing files, and can be combined. For example:
>
  let g:ale_fixers = {
  \   'javascript': [
  \       'DoSomething',
  \       'eslint',
  \       {buffer, lines -> filter(lines, 'v:val !=~ ''^\s*//''')},
  \   ],
  \}

  ALEFix
<
The above example will call a function called `DoSomething` which could act
upon some lines immediately, then run `eslint` from the ALE registry, and
then call a lambda function which will remove every single line comment
from the file.

For buffer-local settings, such as in |g:ale_pattern_options| or in ftplugin
files, a |List| may be used for configuring the fixers instead.
>
  " Same as the above, only a List can be used instead of a Dictionary.
  let b:ale_fixers = [
  \   'DoSomething',
  \   'eslint',
  \   {buffer, lines -> filter(lines, 'v:val !=~ ''^\s*//''')},
  \]

  ALEFix
<
For convenience, a plug mapping is defined for |ALEFix|, so you can set up a
keybind easily for fixing files. >

  " Bind F8 to fixing problems with ALE
  nmap <F8> <Plug>(ale_fix)
<
Files can be fixed automatically with the following options, which are all off
by default.

|g:ale_fix_on_save| - Fix files when they are saved.


===============================================================================
5. Language Server Protocol Support                                   *ale-lsp*

ALE offers some support for integrating with Language Server Protocol (LSP)
servers. LSP linters can be used in combination with any other linter, and
will automatically connect to LSP servers when needed. ALE also supports
`tsserver` for TypeScript, which uses a different but very similar protocol.

ALE supports the following LSP/tsserver features.

1. Diagnostics/linting - Enabled via selecting linters as usual.
2. Completion (Only for tsserver)
3. Go to definition


-------------------------------------------------------------------------------
5.1 Completion                                                 *ale-completion*

NOTE: At the moment, only `tsserver` for TypeScript code is supported for
completion.

ALE offers limited support for automatic completion of code while you type.
Completion is only supported while a least one LSP linter is enabled. ALE
will only suggest symbols provided by the LSP servers.

Suggestions will be made while you type after completion is enabled.
Completion can be enabled by setting |g:ale_completion_enabled| to `1`. The
delay for completion can be configured with |g:ale_completion_delay|. ALE will
only suggest so many possible matches for completion. The maximum number of
items can be controlled with |g:ale_completion_max_suggestions|.

If you don't like some of the suggestions you see, you can filter them out
with |g:ale_completion_excluded_words| or |b:ale_completion_excluded_words|.


-------------------------------------------------------------------------------
5.2 Go To Definition                                     *ale-go-to-definition*

ALE supports jumping to the files and locations where symbols are defined
through any enabled LSP linters. The locations ALE will jump to depend on the
information returned by LSP servers. The following commands are supported:

|ALEGoToDefinition|      - Open the definition of the symbol under the cursor.
|ALEGoToDefinitionInTab| - The same, but for opening the file in a new tab.


-------------------------------------------------------------------------------
5.3 Find References                                       *ale-find-references*

ALE supports finding references for symbols though any enabled LSP linters.
ALE will display a preview window showing the places where a symbol is
referenced in a codebase when a command is run. The following commands are
supported:

|ALEFindReferences| - Find references for the word under the cursor.


-------------------------------------------------------------------------------
5.4 Hovering                                                        *ale-hover*

ALE supports "hover" information for printing brief information about symbols
at the cursor taken from LSP linters. The following commands are supported:

|ALEHover| - Print information about the symbol at the cursor.

If |b:ale_set_balloons| is set to `1` and your version of Vim supports the
|balloon_show()| function, then "hover" information also show up when you move
the mouse over a symbol in a buffer. Diagnostic information will take priority
over hover information for balloons. If a line contains a problem, that
problem will be displayed in a balloon instead of hover information.


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

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|.


g:ale_cache_executable_check_failures   *g:ale_cache_executable_check_failures*

  Type: |Number|
  Default: undefined

  When set to `1`, ALE will cache failing executable checks for linters. By
  default, only executable checks which succeed will be cached.

  When this option is set to `1`, Vim will have to be restarted after new
  executables are installed for ALE to be able to run linters for those
  executables.


g:ale_change_sign_column_color                 *g:ale_change_sign_column_color*

  Type: |Number|
  Default: `0`

  When set to `1`, this option will set different highlights for the sign
  column itself when ALE reports problems with a file. This option can be
  combined with |g:ale_sign_column_always|.

  ALE uses the following highlight groups for highlighting the sign column:

  `ALESignColumnWithErrors`    -  Links to `error` by default.
  `ALESignColumnWithoutErrors` -  Uses the value for `SignColumn` by default.

  The sign column color can only be changed globally in Vim. The sign column
  might produce unexpected results if editing different files in split
  windows.


g:ale_command_wrapper                                   *g:ale_command_wrapper*
                                                        *b:ale_command_wrapper*
  Type: |String|
  Default: `''`

  An option for wrapping all commands that ALE runs, for linters, fixers,
  and LSP commands. This option can be set globally, or for specific buffers.

  This option can be used to apply nice to all commands. For example: >

    " Prefix all commands with nice.
    let g:ale_command_wrapper = 'nice -n5'
<
  Use the |ALEInfo| command to view the commands that are run. All of the
  arguments for commands will be put on the end of the wrapped command by
  default. A `%*` marker can be used to spread the arguments in the wrapped
  command. >

    " Has the same effect as the above.
    let g:ale_command_wrapper = 'nice -n5 %*'
<

  For passing all of the arguments for a command as one argument to a wrapper,
  `%@` can be used instead. >

    " Will result in say: /bin/bash -c 'other-wrapper -c "some command" -x'
    let g:ale_command_wrapper = 'other-wrapper -c %@ -x'
<
  For commands including `&&` or `;`, only the last command in the list will
  be passed to the wrapper. `&&` is most commonly used in ALE to change the
  working directory before running a command.


g:ale_completion_delay                                 *g:ale_completion_delay*

  Type: |Number|
  Default: `100`

  The number of milliseconds before ALE will send a request to a language
  server for completions after you have finished typing.

  See |ale-completion|


g:ale_completion_enabled                             *g:ale_completion_enabled*

  Type: |Number|
  Default: `0`

  When this option is set to `1`, completion support will be enabled.

  See |ale-completion|


g:ale_completion_excluded_words               *g:ale_completion_excluded_words*
                                              *b:ale_completion_excluded_words*
  Type: |List|
  Default: `[]`

  This option can be set to a list of |String| values for "words" to exclude
  from completion results, as in the words for |complete-items|. The strings
  will be matched exactly in a case-sensitive manner. (|==#|)

  This setting can be configured in ftplugin files with buffer variables, so
  that different lists can be used for different filetypes. For example: >

  " In ~/.vim/ftplugin/typescript.vim

  " Don't suggest `it` or `describe` so we can use snippets for those words.
  let b:ale_completion_excluded_words = ['it', 'describe']
<

g:ale_completion_max_suggestions             *g:ale_completion_max_suggestions*

  Type: |Number|
  Default: `50`

  The maximum number of items ALE will suggest in completion menus for
  automatic completion.

  Setting this number higher will require more processing time, and may
  suggest too much noise. Setting this number lower will require less
  processing time, but some suggestions will not be included, so you might not
  be able to see the suggestions you want.

  Adjust this option as needed, depending on the complexity of your codebase
  and your available processing power.


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_delay                                             *g:ale_echo_delay*
                                                             *b:ale_echo_delay*
  Type: |Number|
  Default: `10`

  Given any integer, this option controls the number of milliseconds before
  ALE will echo a message for a problem near the cursor.

  The value can be increased to decrease the amount of processing ALE will do
  for files displaying a large number of problems.


g:ale_echo_msg_error_str                             *g:ale_echo_msg_error_str*

  Type: |String|
  Default: `'Error'`

  The string used for `%severity%` for errors. See |g:ale_echo_msg_format|


g:ale_echo_msg_format                                   *g:ale_echo_msg_format*
b:ale_echo_msg_format                                   *b:ale_echo_msg_format*

  Type: |String|
  Default: `'%code: %%s'`

  This variable defines a message format for echoed messages. The following
  sequences of characters will be replaced.

    `%s`           - replaced with the text for the problem
    `%...code...% `- replaced with the error code
    `%linter%`     - replaced with the name of the linter
    `%severity%`   - replaced withe severity of the problem

  The strings for `%severity%` can be configured with the following options.

    |g:ale_echo_msg_error_str|   - Defaults to `'Error'`
    |g:ale_echo_msg_info_str|    - Defaults to `'Info'`
    |g:ale_echo_msg_warning_str| - Defaults to `'Warning'`

  `%code%` is replaced with the error code, and replaced with an empty string
  when there is no error code. Any extra characters between the percent signs
  will be printed when an error code is present. For example, a message like
  `(error code): message` will be printed for `'%(code): %%s'` and simply the
  message will be printed when there is no code.

  |g:ale_echo_cursor| needs to be set to 1 for messages to be displayed.

  The echo message format can also be configured separately for each buffer,
  so different formats can be used for differnt languages. (Say in ftplugin
  files.)


g:ale_echo_msg_info_str                               *g:ale_echo_msg_info_str*

  Type: |String|
  Default: `'Info'`

  The string used for `%severity%` for info. See |g:ale_echo_msg_format|


g:ale_echo_msg_warning_str                         *g:ale_echo_msg_warning_str*

  Type: |String|
  Default: `'Warning'`

  The string used for `%severity%` for warnings. See |g:ale_echo_msg_format|


g:ale_enabled                                                   *g:ale_enabled*
                                                                *b:ale_enabled*

  Type: |Number|
  Default: `1`

  When set to `0`, this option will completely disable ALE, such that no
  error checking will be performed, etc. ALE can be toggled on and off with
  the |ALEToggle| command, which changes this option.

  ALE can be disabled in each buffer by setting `let b:ale_enabled = 0`
  Disabling ALE based on filename patterns can be accomplished by setting
  a regular expression for |g:ale_pattern_options|. For example: >

  " Disable linting for all minified JS files.
  let g:ale_pattern_options = {'\.min.js$': {'ale_enabled': 0}}
<

  See |g:ale_pattern_options| for more information on that option.


g:ale_fixers                                                     *g:ale_fixers*
                                                                 *b:ale_fixers*

  Type: |Dictionary|
  Default: `{}`

  A mapping from filetypes to |List| values for functions for fixing errors.
  See |ale-fix| for more information.

  This variable can be overridden with variables in each buffer.
  `b:ale_fixers` can be set to a |List| of callbacks instead, which can be
  more convenient.


g:ale_fix_on_save                                           *g:ale_fix_on_save*
b:ale_fix_on_save                                           *b:ale_fix_on_save*

  Type: |Number|
  Default: `0`

  When set to 1, ALE will fix files when they are saved.

  If |g:ale_lint_on_save| is set to 1, files will be checked with linters
  after files are fixed, only when the buffer is open, or re-opened. Changes
  to the file will be saved to the file on disk.

  Fixing files can be disabled or enabled for individual buffers by setting
  `b:ale_fix_on_save` to `0` or `1`.


g:ale_history_enabled                                   *g:ale_history_enabled*

  Type: |Number|
  Default: `1`

  When set to `1`, ALE will remember the last few commands which were run
  for every buffer which is open. This information can be viewed with the
  |ALEInfo| command. The size of the buffer can be controlled with the
  |g:ale_max_buffer_history_size| option.

  This option can be disabled if storing a command history is not desired.


g:ale_history_log_output                             *g:ale_history_log_output*

  Type: |Number|
  Default: `1`

  When set to `1`, ALE will store the output of commands which have completed
  successfully in the command history, and the output will be displayed when
  using |ALEInfo|.

  |g:ale_history_enabled| must be set to `1` for this output to be stored or
  printed.

  Some memory will be consumed by this option. It is very useful for figuring
  out what went wrong with linters, and for bug reports. Turn this option off
  if you want to save on some memory usage.


g:ale_keep_list_window_open                       *g:ale_keep_list_window_open*
                                                  *b:ale_keep_list_window_open*
  Type: |Number|
  Default: `0`

  When set to `1`, this option will keep the loclist or quickfix windows event
  after all warnings/errors have been removed for files. By default the
  loclist or quickfix windows will be closed automatically when there are no
  warnings or errors.

  See |g:ale_open_list|


g:ale_list_window_size                                 *g:ale_list_window_size*
                                                       *b:ale_list_window_size*
  Type: |Number|
  Default: `10`

  This number configures the number of lines to set for the height of windows
  opened automatically for ALE problems. The default of `10` matches the Vim
  default height.

  See |g:ale_open_list| for information on automatically opening windows
  for quickfix or the loclist.


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 `always`, `insert`, or `normal`.


g:ale_lint_on_enter                                       *g:ale_lint_on_enter*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, the |BufWinEnter| 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.

  The |FileChangedShellPost| and |BufEnter| events will be used to check if
  files have been changed outside of Vim. If a file is changed outside of
  Vim, it will be checked when it is next opened.

  A |BufWinLeave| event will be used to look for the |E924|, |E925|, or |E926|
  errors after moving from a loclist or quickfix window to a new buffer. If
  prompts for these errors are opened after moving to new buffers, then ALE
  will automatically send the `<CR>` key needed to close the prompt.


g:ale_lint_on_filetype_changed                 *g:ale_lint_on_filetype_changed*

  Type: |Number|
  Default: `1`

  This option will cause ALE to run whenever the filetype is changed. A short
  delay will be used before linting will be done, so the filetype can be
  changed quickly several times in a row, but resulting in only one lint
  cycle.

  If |g:ale_lint_on_enter| is set to `0`, then ALE will not lint a file when
  the filetype is initially set. Otherwise ALE would still lint files when
  buffers are opened, and the option for doing so is turned off.


g:ale_lint_on_save                                         *g:ale_lint_on_save*

  Type: |Number|
  Default: `1`

  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_lint_on_text_changed                         *g:ale_lint_on_text_changed*

  Type: |String|
  Default: `always`

  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 `never`. 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. This option can also be set to `insert` or `normal`
  to lint when text is changed only in insert or normal mode respectively.


g:ale_lint_on_insert_leave                         *g:ale_lint_on_insert_leave*

  Type: |Number|
  Default: `0`

  When set to `1` in your vimrc file, this option will cause ALE to run
  linters when you leave insert mode.

  ALE will not lint files when you escape insert mode with |CTRL-C| by
  default. You can make ALE lint files with this option when you use |CTRL-C|
  with the following keybind. >

    " Make using Ctrl+C do the same as Escape, to trigger autocmd commands
    inoremap <C-c> <Esc>
<

g:ale_linter_aliases                                     *g:ale_linter_aliases*
                                                         *b: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: >

  {
  \   'Dockerfile': 'dockerfile',
  \   'csh': 'sh',
  \   'plaintex': 'tex',
  \   'systemverilog': 'verilog',
  \   'vimwiki': 'markdown',
  \   'zsh': '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.

  Passing a list of filetypes is also supported. Say you want to lint
  javascript and css embedded in HTML (using linters that support that).
  You could alias `html` like so:

  `let g:ale_linter_aliases = {'html': ['html', 'javascript', 'css']}`

  Note that `html` itself was included as an alias. That is because aliases
  will override the original linters for the aliased filetype.

  Linter aliases can be configured in each buffer with buffer-local variables.
  ALE will first look for aliases for filetypes in the `b:ale_linter_aliases`
  variable, then `g:ale_linter_aliases`, and then a default Dictionary.

  `b:ale_linter_aliases` can be set to a |List|, to tell ALE to load the
  linters for specific filetypes for a given buffer. >

  let b:ale_linter_aliases = ['html', 'javascript', 'css']
<
  No linters will be loaded when the buffer's filetype is empty.

g:ale_linters                                                   *g:ale_linters*
                                                                *b: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.

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

  {
  \   'csh': ['shell'],
  \   'go': ['gofmt', 'golint', 'go vet'],
  \   'help': [],
  \   'perl': ['perlcritic'],
  \   'python': ['flake8', 'mypy', 'pylint'],
  \   'rust': ['cargo'],
  \   'spec': [],
  \   'text': [],
  \   'zsh': ['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 will be run for unspecified filetypes. All available linters can
  be enabled explicitly for a given filetype by passing the string `'all'`,
  instead of a List. >

  let g:ale_linters = {'c': 'all'}
<
  Linters can be configured in each buffer with buffer-local variables. ALE
  will first look for linters for filetypes in the `b:ale_linters` variable,
  then `g:ale_linters`, and then the default Dictionary mentioned above.

  `b:ale_linters` can be set to a List, or the string `'all'`. When linters
  for two different filetypes share the same name, the first linter loaded
  will be used. Any ambiguity can be resolved by using a Dictionary specifying
  which linter to run for which filetype instead. >

  " Use ESLint for the buffer if the filetype includes 'javascript'.
  let b:ale_linters = {'javascript': ['eslint'], 'html': ['tidy']}
  " Use a List for the same setting. This will work in most cases.
  let b:ale_linters = ['eslint', 'tidy']
  " Disable all linters for the buffer.
  let b:ale_linters = []
  " Explicitly enable all available linters for the filetype.
  let b:ale_linters = 'all'
<
  ALE can be configured to disable all linters unless otherwise specified with
  `g:ale_enabled` or `b:ale_enabled` with the option |g:ale_linters_explicit|.


g:ale_linters_explicit                                 *g:ale_linters_explicit*

  Type: |Number|
  Default: `0`

  When set to `1`, only the linters from |g:ale_linters| and |b:ale_linters|
  will be enabled. The default behavior for ALE is to enable as many linters
  as possible, unless otherwise specified.


g:ale_list_vertical                                       *g:ale_list_vertical*
                                                          *b:ale_list_vertical*
  Type: |Number|
  Default: `0`

  When set to `1`, this will cause ALE to open any windows (loclist or
  quickfix) vertically instead of horizontally (|vert| |lopen|) or (|vert|
  |copen|)


g:ale_loclist_msg_format                             *g:ale_loclist_msg_format*
b:ale_loclist_msg_format                             *b:ale_loclist_msg_format*

  Type: |String|
  Default: `g:ale_echo_msg_format`

  This option is the same as |g:ale_echo_msg_format|, but for formatting the
  message used for the loclist and the quickfix list.

  The strings for configuring `%severity%` are also used for this option.


g:ale_max_buffer_history_size                   *g:ale_max_buffer_history_size*

  Type: |Number|
  Default: `20`

  This setting controls the maximum number of commands which will be stored in
  the command history used for |ALEInfo|. Command history will be rotated in
  a FIFO manner. If set to a number <= 0, then the history will be
  continuously set to an empty |List|.

  History can be disabled completely with |g:ale_history_enabled|.


g:ale_max_signs                                               *g:ale_max_signs*
                                                              *b:ale_max_signs*
  Type: |Number|
  Default: `-1`

  When set to any positive integer, ALE will not render any more than the
  given number of signs for any one buffer.

  When set to `0`, no signs will be set, but sign processing will still be
  done, so existing signs can be removed.

  When set to any other value, no limit will be imposed on the number of signs
  set.

  For disabling sign processing, see |g:ale_set_signs|.


g:ale_maximum_file_size                               *g:ale_maximum_file_size*
                                                      *b:ale_maximum_file_size*
  Type: |Number|
  Default: undefined

  A maximum file size in bytes for ALE to check. If set to any positive
  number, ALE will skip checking files larger than the given size.


g:ale_open_list                                               *g:ale_open_list*
                                                              *b:ale_open_list*
  Type: |Number| or |String|
  Default: `0`

  When set to `1`, this will cause ALE to automatically open a window for the
  loclist (|lopen|) or for the quickfix list instead if |g:ale_set_quickfix|
  is `1`. (|copen|)

  When set to `'on_save'`, ALE will only open the loclist after buffers have
  been saved. The list will be opened some time after buffers are saved and
  any linter for a buffer returns results.

  The window will be kept open until all warnings or errors are cleared,
  including those not set by ALE, unless |g:ale_keep_list_window_open| is set
  to `1`, in which case the window will be kept open when no problems are
  found.

  The window size can be configured with |g:ale_list_window_size|.

  Windows can be opened vertically with |g:ale_list_vertical|.

  If you want to close the loclist window automatically when the buffer is
  closed, you can set up the following |autocmd| command: >

  augroup CloseLoclistWindowGroup
    autocmd!
    autocmd QuitPre * if empty(&buftype) | lclose | endif
  augroup END
<

g:ale_pattern_options                                   *g:ale_pattern_options*

  Type: |Dictionary|
  Default: `{}`

  This option maps regular expression patterns to |Dictionary| values for
  buffer variables. This option can be set to automatically configure
  different settings for different files. For example: >

  " Use just ESLint for linting and fixing files which end in '.foo.js'
  let g:ale_pattern_options = {
  \   '\.foo\.js$': {
  \       'ale_linters': ['eslint'],
  \       'ale_fixers': ['eslint'],
  \   },
  \}
<
  See |b:ale_linters| and |b:ale_fixers| for information for those options.

  Filenames are matched with |match()|, and patterns depend on the |magic|
  setting, unless prefixed with the special escape sequences like `'\v'`, etc.
  The patterns can match any part of a filename. The absolute path of the
  filename will be used for matching, taken from `expand('%:p')`.

  The options for every match for the filename will be applied, with the
  pattern keys sorted in alphabetical order. Options for `'zebra'` will
  override the options for `'alpha'` for a filename `alpha-zebra`.


g:ale_pattern_options_enabled                   *g:ale_pattern_options_enabled*

  Type: |Number|
  Default: `!empty(g:ale_pattern_options)`

  This option can be used for turning the behaviour of setting
  |g:ale_pattern_options| on or off. By default, setting a single key for
  |g:ale_pattern_options| will turn this option on, as long as the setting is
  configured before ALE is loaded.


g:ale_set_balloons                                         *g:ale_set_balloons*
                                                           *b:ale_set_balloons*

  Type: |Number|
  Default: `(has('balloon_eval') && has('gui_running'))`
           `|| (has('balloon_eval_term') && !has('gui_running'))`

  When this option is set to `1`, balloon messages will be displayed for
  problems or hover information if available.

  Problems nearest to the line the mouse cursor is over will be displayed. If
  there are no problems to show, and one of the linters is an LSP linter
  supporting "Hover" information, per |ale-hover|, then brief information
  about the symbol under the cursor will be displayed in a balloon.

  `b:ale_set_balloons` can be set to `0` to disable balloons for a buffer.
  Balloons cannot be enabled for a specific buffer when not initially enabled
  globally.

  Balloons will not be shown when |g:ale_enabled| or |b:ale_enabled| is `0`.


g:ale_set_balloons_legacy_echo                 *g:ale_set_balloons_legacy_echo*
                                               *b:ale_set_balloons_legacy_echo*
  Type: |Number|
  Default: undefined

  If set to `1`, moving your mouse over documents in Vim will make ALE ask
  `tsserver` or `LSP` servers for information about the symbol where the mouse
  cursor is, and print that information into Vim's echo line. This is an
  option for supporting older versions of Vim which do not properly support
  balloons in an asynchronous manner.

  If your version of Vim supports the |balloon_show| function, then this
  option does nothing meaningful.


g:ale_set_highlights                                     *g:ale_set_highlights*

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

  When this option is set to `1`, highlights will be set for problems.

  ALE will use the following highlight groups for problems:

  |ALEError|        - Items with `'type': 'E'`
  |ALEWarning|      - Items with `'type': 'W'`
  |ALEInfo.|        - Items with `'type': 'I'`
  |ALEStyleError|   - Items with `'type': 'E'` and `'sub_type': 'style'`
  |ALEStyleWarning| - Items with `'type': 'W'` and `'sub_type': 'style'`

  When |g:ale_set_signs| is set to `0`, the following highlights for entire
  lines will be set.

  |ALEErrorLine|   - All items with `'type': 'E'`
  |ALEWarningLine| - All items with `'type': 'W'`
  |ALEInfoLine|    - All items with `'type': 'I'`

  Vim can only highlight the characters up to the last column in a buffer for
  match highlights, whereas the line highlights when signs are enabled will
  run to the edge of the screen.


g:ale_set_loclist                                           *g:ale_set_loclist*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, the |loclist| will be populated 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_quickfix                                         *g:ale_set_quickfix*

  Type: |Number|
  Default: `0`

  When this option is set to `1`, the |quickfix| list will be populated with
  any problems which are found by ALE, instead of the |loclist|. The loclist
  will never be populated when this option is on.

  Problems from every buffer ALE has checked will be included in the quickfix
  list, which can be checked with |:copen|. Problems will be de-duplicated.

  This feature should not be used in combination with tools for searching for
  matches and commands like |:cfdo|, as ALE will replace the quickfix list
  pretty frequently. If you wish to use such tools, you should populate the
  loclist instead.


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 problems appear in the file.

  ALE will use the following highlight groups for problems:

  |ALEErrorSign|        - Items with `'type': 'E'`
  |ALEWarningSign|      - Items with `'type': 'W'`
  |ALEInfoSign|         - Items with `'type': 'I'`
  |ALEStyleErrorSign|   - Items with `'type': 'E'` and `'sub_type': 'style'`
  |ALEStyleWarningSign| - Items with `'type': 'W'` and `'sub_type': 'style'`

  In addition to the style of the signs, the style of lines where signs appear
  can be configured with the following highlights:

  |ALEErrorLine|   - All items with `'type': 'E'`
  |ALEWarningLine| - All items with `'type': 'W'`
  |ALEInfoLine|    - All items with `'type': 'I'`

  The markers for the highlights can be customized with the following options:

  |g:ale_sign_error|
  |g:ale_sign_warning|
  |g:ale_sign_info|
  |g:ale_sign_style_error|
  |g:ale_sign_style_warning|

  When multiple problems exist on the same line, the signs will take
  precedence in the order above, from highest to lowest.

  To limit the number of signs ALE will set, see |g:ale_max_signs|.


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: `'>>'`

  The sign for errors in the sign gutter.


g:ale_sign_info                                               *g:ale_sign_info*

  Type: |String|
  Default: `g:ale_sign_warning`

  The sign for "info" markers in the sign gutter.


g:ale_sign_style_error                                 *g:ale_sign_style_error*

  Type: |String|
  Default: `g:ale_sign_error`

  The sign for style errors in the sign gutter.


g:ale_sign_style_warning                             *g:ale_sign_style_warning*

  Type: |String|
  Default: `g:ale_sign_warning`

  The sign for style warnings in the sign gutter.


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_sign_warning                                         *g:ale_sign_warning*

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

  The sign for warnings in the sign gutter.


g:ale_type_map                                                 *g:ale_type_map*
                                                               *b:ale_type_map*
  Type: |Dictionary|
  Default: `{}`

  This option can be set re-map problem types for linters. Each key in the
  |Dictionary| should be the name of a linter, and each value must be a
  |Dictionary| mapping problem types from one type to another. The following
  types are supported:

  `'E'`  - `{'type': 'E'}`
  `'ES'` - `{'type': 'E', 'sub_type': 'style'}`
  `'W'`  - `{'type': 'W'}`
  `'WS'` - `{'type': 'W', 'sub_type': 'style'}`
  `'I'`  - `{'type': 'I'}`

  For example, if you want to turn flake8 errors into warnings, you can write
  the following: >

  let g:ale_type_map = {'flake8': {'ES': 'WS', 'E': 'W'}}
<
  If you wanted to turn style errors and warnings into regular errors and
  warnings, you can write the following: >

  let g:ale_type_map = {'flake8': {'ES': 'E', 'WS': 'W'}}
<
  Type maps can be set per-buffer with `b:ale_type_map`.


g:ale_use_global_executables                     *g:ale_use_global_executables*

  Type: |Number|
  Default: not set

  This option can be set to change the default for all `_use_global` options.
  This option must be set before ALE is loaded, preferably in a vimrc file.

  See |ale-integrations-local-executables| for more information on those
  options.


g:ale_virtualenv_dir_names                         *g:ale_virtualenv_dir_names*
b:ale_virtualenv_dir_names                         *b:ale_virtualenv_dir_names*

  Type: |List|
  Default: `['.env', 'env', 've-py3', 've', 'virtualenv', 'venv']`

  A list of directory names to be used when searching upwards from Python
  files to discover virtulenv directories with.

  For directory named `'foo'`, ALE will search for `'foo/bin/activate'`
  (`foo\Scripts\activate\` on Windows) in all directories on and above the
  directory containing the Python file to find virtualenv paths.


g:ale_warn_about_trailing_blank_lines   *g:ale_warn_about_trailing_blank_lines*
b:ale_warn_about_trailing_blank_lines   *b:ale_warn_about_trailing_blank_lines*

  Type: |Number|
  Default: `1`

  When this option is set to `1`, warnings about trailing blank lines will be
  shown.

  This option behaves similarly to |g:ale_warn_about_trailing_whitespace|.


g:ale_warn_about_trailing_whitespace     *g:ale_warn_about_trailing_whitespace*
b:ale_warn_about_trailing_whitespace     *b: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. If warnings are too irritating while editing buffers,
  and you have configured Vim to automatically remove trailing whitespace,
  you can disable these warnings 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.

  This option may be configured on a per buffer basis.


g:ale_windows_node_executable_path         *g:ale_windows_node_executable_path*
                                           *b:ale_windows_node_executable_path*

  Type: |String|
  Default: `'node.exe'`

  This variable is used as the path to the executable to use for executing
  scripts with Node.js on Windows.

  For Windows, any file with a `.js` file extension needs to be executed with
  the node executable explicitly. Otherwise, Windows could try and open the
  scripts with other applications, like a text editor. Therefore, these
  scripts are executed with whatever executable is configured with this
  setting.


-------------------------------------------------------------------------------
6.1. Highlights                                                *ale-highlights*

ALEError                                                             *ALEError*

  Default: `highlight link ALEError SpellBad`

  The highlight used for highlighted errors. See |g:ale_set_highlights|.


ALEErrorLine                                                     *ALEErrorLine*

  Default: Undefined

  The highlight for an entire line where errors appear. Only the first
  line for a problem will be highlighted.

  See |g:ale_set_signs| and |g:ale_set_highlights|.


ALEErrorSign                                                     *ALEErrorSign*

  Default: `highlight link ALEErrorSign error`

  The highlight used for error signs. See |g:ale_set_signs|.


ALEInfo                                                              *ALEInfo.*
                                                            *ALEInfo-highlight*
  Default: `highlight link ALEInfo ALEWarning`

  The highlight used for highlighted info messages. See |g:ale_set_highlights|.


ALEInfoSign                                                       *ALEInfoSign*

  Default: `highlight link ALEInfoSign ALEWarningSign`

  The highlight used for info message signs. See |g:ale_set_signs|.


ALEInfoLine                                                       *ALEInfoLine*

  Default: Undefined

  The highlight for entire lines where info messages appear. Only the first
  line for a problem will be highlighted.

  See |g:ale_set_signs| and |g:ale_set_highlights|.


ALEStyleError                                                   *ALEStyleError*

  Default: `highlight link ALEStyleError ALEError`

  The highlight used for highlighted style errors. See |g:ale_set_highlights|.


ALEStyleErrorSign                                           *ALEStyleErrorSign*

  Default: `highlight link ALEStyleErrorSign ALEErrorSign`

  The highlight used for style error signs. See |g:ale_set_signs|.


ALEStyleWarning                                               *ALEStyleWarning*

  Default: `highlight link ALEStyleWarning ALEError`

  The highlight used for highlighted style warnings. See |g:ale_set_highlights|.


ALEStyleWarningSign                                       *ALEStyleWarningSign*

  Default: `highlight link ALEStyleWarningSign ALEWarningSign`

  The highlight used for style warning signs. See |g:ale_set_signs|.


ALEWarning                                                         *ALEWarning*

  Default: `highlight link ALEWarning SpellCap`

  The highlight used for highlighted warnings. See |g:ale_set_highlights|.


ALEWarningLine                                                 *ALEWarningLine*

  Default: Undefined

  The highlight for entire lines where warnings appear. Only the first line
  for a problem will be highlighted.

  See |g:ale_set_signs| and |g:ale_set_highlights|.


ALEWarningSign                                                 *ALEWarningSign*

  Default: `highlight link ALEWarningSign todo`

  The highlight used for warning signs. See |g:ale_set_signs|.


-------------------------------------------------------------------------------
6.2. Options for write-good                            *ale-write-good-options*

The options for the write-good linter are global because it does not make
sense to have them specified on a per-language basis.

g:ale_writegood_executable                         *g:ale_writegood_executable*
                                                   *b:ale_writegood_executable*
  Type: |String|
  Default: `'writegood'`

  See |ale-integrations-local-executables|


g:ale_writegood_options                               *g:ale_writegood_options*
                                                      *b:ale_writegood_options*
  Type: |String|
  Default: `''`

  This variable can be set to pass additional options to writegood.


g:ale_writegood_use_global                         *g:ale_writegood_use_global*
                                                   *b:ale_writegood_use_global*
  Type: |Number|
  Default: `get(g:, 'ale_use_global_executables', 0)`

  See |ale-integrations-local-executables|


===============================================================================
7. Integration Documentation                                 *ale-integrations*

Linter and fixer options are documented in individual help files. See the
table of contents at |ale-contents|.

Every option for programs can be set globally, or individually for each
buffer.  For example, `b:ale_python_flake8_executable` will override any
values set for `g:ale_python_flake8_executable`.

                                           *ale-integrations-local-executables*

Some tools will prefer to search for locally-installed executables, unless
configured otherwise. For example, the `eslint` linter will search for
various executable paths in `node_modules`. The `flake8` linter will search
for virtualenv directories.

If you prefer to use global executables for those tools, set the relevant
`_use_global` and `_executable` options for those linters. >

  " Use the global executable with a special name for eslint.
  let g:ale_javascript_eslint_executable = 'special-eslint'
  let g:ale_javascript_eslint_use_global = 1

  " Use the global executable with a special name for flake8.
  let g:ale_python_flake8_executable = '/foo/bar/flake8'
  let g:ale_python_flake8_use_global = 1
<

|g:ale_use_global_executables| can be set to `1` in your vimrc file to make
ALE use global executables for all linters by default.

The option |g:ale_virtualenv_dir_names| controls the local virtualenv paths
ALE will use to search for Python executables.


===============================================================================
8. Commands/Keybinds                                             *ale-commands*

ALEFindReferences                                           *ALEFindReferences*

  Find references in the codebase for the symbol under the cursor using the
  enabled LSP linters for the buffer. ALE will display a preview window
  containing the results if some references are found.

  The window can be navigated using the usual Vim navigation commands. The
  Enter key (`<CR>`) can be used to jump to a referencing location, or the `t`
  key can be used to jump to the location in a new tab.

  You can jump back to the position you were at before going to a reference of
  something with jump motions like CTRL-O. See |jump-motions|.

  A plug mapping `<Plug>(ale_find_references)` is defined for this command.

ALEFix                                                                 *ALEFix*

  Fix problems with the current buffer. See |ale-fix| for more information.

  A plug mapping `<Plug>(ale_fix)` is defined for this command.


ALEFixSuggest                                                   *ALEFixSuggest*

  Suggest tools that can be used to fix problems in the current buffer.

  See |ale-fix| for more information.


ALEGoToDefinition                                           *ALEGoToDefinition*

  Jump to the definition of a symbol under the cursor using the enabled LSP
  linters for the buffer. ALE will jump to a definition if an LSP server
  provides a location to jump to. Otherwise, ALE will do nothing.

  You can jump back to the position you were at before going to the definition
  of something with jump motions like CTRL-O. See |jump-motions|.

  A plug mapping `<Plug>(ale_go_to_definition)` is defined for this command.


ALEGoToDefinitionInTab                                 *ALEGoToDefinitionInTab*

  The same as |ALEGoToDefinition|, but opens results in a new tab.

  A plug mapping `<Plug>(ale_go_to_definition_in_tab)` is defined for this
  command.


ALEHover                                                             *ALEHover*

  Print brief information about the symbol under the cursor, taken from any
  available LSP linters. There may be a small non-blocking delay before
  information is printed.

  NOTE: In Vim 8, long messages will be shown in a preview window, as Vim 8
  does not support showing a prompt to press enter to continue for long
  messages from asynchronous callbacks.

  A plug mapping `<Plug>(ale_hover)` is defined for this command.

                                                                     *:ALELint*
ALELint                                                               *ALELint*

  Run ALE once for the current buffer. This command can be used to run ALE
  manually, instead of automatically, if desired.

  This command will also run linters where `lint_file` is set to `1`, or in
  other words linters which check the file instead of the Vim buffer.

  A plug mapping `<Plug>(ale_lint)` is defined for this command.


ALEPrevious                                                       *ALEPrevious*
ALEPreviousWrap                                               *ALEPreviousWrap*
ALENext                                                               *ALENext*
ALENextWrap                                                       *ALENextWrap*
ALEFirst                                                             *ALEFirst*
ALELast                                                               *ALELast*
                                                      *ale-navigation-commands*

  Move between warnings or errors in a buffer. ALE will only navigate between
  the errors or warnings it generated, even if both |g:ale_set_quickfix|
  and |g:ale_set_loclist| are set to `0`.

  `ALEPrevious` and `ALENext` will stop at the top and bottom of a file, while
  `ALEPreviousWrap` and `ALENextWrap` will wrap around the file to find
  the last or first warning or error in the file, respectively.

  `ALEFirst` goes to the first error or warning in the buffer, while `ALELast`
  goes to the last one.

  The following |<Plug>| mappings are defined for the commands: >
  <Plug>(ale_previous) - ALEPrevious
  <Plug>(ale_previous_wrap) - ALEPreviousWrap
  <Plug>(ale_next) - ALENext
  <Plug>(ale_next_wrap) - ALENextWrap
  <Plug>(ale_first) - ALEFirst
  <Plug>(ale_last) - ALELast
<
  For example, these commands could be bound to the keys Ctrl + j
  and Ctrl + k: >

  " Map movement through errors without wrapping.
  nmap <silent> <C-k> <Plug>(ale_previous)
  nmap <silent> <C-j> <Plug>(ale_next)
  " OR map keys to use wrapping.
  nmap <silent> <C-k> <Plug>(ale_previous_wrap)
  nmap <silent> <C-j> <Plug>(ale_next_wrap)
<

ALEToggle                                                           *ALEToggle*
ALEEnable                                                           *ALEEnable*
ALEDisable                                                         *ALEDisable*
ALEToggleBuffer                                               *ALEToggleBuffer*
ALEEnableBuffer                                               *ALEEnableBuffer*
ALEDisableBuffer                                             *ALEDisableBuffer*

  `ALEToggle`, `ALEEnable`, and `ALEDisable` enable or disable ALE linting,
  including all of its autocmd events, loclist items, quickfix items, signs,
  current jobs, etc., globally. Executing any of these commands will change
  the |g:ale_enabled| variable.

  ALE can be disabled or enabled for only a single buffer with
  `ALEToggleBuffer`, `ALEEnableBuffer`, and `ALEDisableBuffer`. Disabling ALE
  for a buffer will not remove autocmd events, but will prevent ALE from
  checking for problems and reporting problems for whatever buffer the
  `ALEDisableBuffer` or `ALEToggleBuffer` command is executed from. These
  commands can be used for temporarily disabling ALE for a buffer. These
  commands will modify the |b:ale_enabled| variable.

  ALE linting cannot be enabled for a single buffer when it is disabled
  globally, as disabling ALE globally removes the autocmd events needed to
  perform linting with.

  The following plug mappings are defined, for conveniently defining keybinds:

  |ALEToggle|        - `<Plug>(ale_toggle)`
  |ALEEnable|        - `<Plug>(ale_enable)`
  |ALEDisable|       - `<Plug>(ale_disable)`
  |ALEToggleBuffer|  - `<Plug>(ale_toggle_buffer)`
  |ALEEnableBuffer|  - `<Plug>(ale_enable_buffer)`
  |ALEDisableBuffer| - `<Plug>(ale_disable_buffer)`

  For removing problems reported by ALE, but leaving ALE enabled, see
  |ALEReset| and |ALEResetBuffer|.

                                                                   *:ALEDetail*
ALEDetail                                                           *ALEDetail*

  Show the full linter message for the current line in the preview window.
  This will only have an effect on lines that contain a linter message. The
  preview window can be easily closed with the `q` key.

  A plug mapping `<Plug>(ale_detail)` is defined for this command.


                                                                     *:ALEInfo*
ALEInfo                                                               *ALEInfo*
ALEInfoToClipboard                                         *ALEInfoToClipboard*

  Print runtime information about ALE, including the values of global and
  buffer-local settings for ALE, the linters that are enabled, the commands
  that have been run, and the output of commands.

  ALE will log the commands that are run by default. If you wish to disable
  this, set |g:ale_history_enabled| to `0`. Because it could be expensive, ALE
  does not remember the output of recent commands by default. Set
  |g:ale_history_log_output| to `1` to enable logging of output for commands.
  ALE will only log the output captured for parsing problems, etc.

  The command `:ALEInfoToClipboard` can be used to output ALEInfo directly to
  your clipboard. This might not work on every machine.

  `:ALEInfoToFile` will write the ALE runtime information to a given filename.
  The filename works just like |:w|.


ALEReset                                                             *ALEReset*
ALEResetBuffer                                                 *ALEResetBuffer*

  `ALEReset` will remove all problems reported by ALE for all buffers.
  `ALEResetBuffer` will remove all problems reported for a single buffer.

  Either command will leave ALE linting enabled, so ALE will report problems
  when linting is performed again. See |ale-lint| for more information.

  The following plug mappings are defined, for conveniently defining keybinds:

  |ALEReset|       - `<Plug>(ale_reset)`
  |ALEResetBuffer| - `<Plug>(ale_reset_buffer)`

  ALE can be disabled globally or for a buffer with |ALEDisable| or
  |ALEDisableBuffer|.


ALEStopAllLSPs                                                 *ALEStopAllLSPs*

  `ALEStopAllLSPs` will close and stop all channels and jobs for all LSP-like
  clients, including tsserver, remove all of the data stored for them, and
  delete all of the problems found for them, updating every linted buffer.

  This command can be used when LSP clients mess up and need to be restarted.


===============================================================================
9. API                                                                *ale-api*

ale#Queue(delay, [linting_flag, buffer_number])                   *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

  An optional `linting_flag` argument can be given. If `linting_flag`
  is `'lint_file'`, then linters where the `lint_file` option is set to `1` will be
  run. Linters with `lint_file` set to `1` are not run by default.

  An optional `buffer_number` argument can be given for specifying the buffer
  to check. The active buffer (`bufnr('')`) will be checked by default.

                                                                *ale-cool-down*
  If an exception is thrown when queuing/running ALE linters, ALE will enter
  a cool down period where it will stop checking anything for a short period
  of time. This is to prevent ALE from seriously annoying users if a linter
  is broken, or when developing ALE itself.


ale#engine#CreateDirectory(buffer)               *ale#engine#CreateDirectory()*

  Create a new temporary directory with a unique name, and manage that
  directory with |ale#engine#ManageDirectory()|, so it will be removed as
  soon as possible.

  It is advised to only call this function from a callback function for
  returning a linter command to run.


ale#engine#EscapeCommandPart(command_part)     *ale#engine#EscapeCommandPart()*

  Given a |String|, return a |String| with all `%` characters replaced with
  `%%` instead. This function can be used to escape strings which are
  dynamically generated for commands before handing them over to ALE,
  so that ALE doesn't treat any strings with `%` formatting sequences
  specially.


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

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

  A reference to the buffer's list of problems will be returned. The list must
  be copied before applying |map()| or |filter()|.


ale#engine#IsCheckingBuffer(buffer)             *ale#engine#IsCheckingBuffer()*

  Given a buffer number, returns `1` when ALE is busy checking that buffer.

  This function can be used for status lines, tab names, etc.


ale#engine#ManageFile(buffer, filename)               *ale#engine#ManageFile()*

  Given a buffer number for a buffer currently running some linting tasks
  and a filename, register a filename with ALE for automatic deletion after
  linting is complete, or when Vim exits.

  If Vim exits suddenly, ALE will try its best to remove temporary files, but
  ALE cannot guarantee with absolute certainty that the files will be removed.
  It is advised to create temporary files in the operating system's managed
  temporary file directory, such as with |tempname()|.

  Directory names should not be given to this function. ALE will only delete
  files and symlinks given to this function. This is to prevent entire
  directories from being accidentally deleted, say in cases of writing
  `dir . '/' . filename` where `filename` is actually `''`, etc. ALE instead
  manages directories separetly with the |ale#engine#ManageDirectory| function.


ale#engine#ManageDirectory(buffer, directory)    *ale#engine#ManageDirectory()*

  Like |ale#engine#ManageFile()|, but directories and all of their contents
  will be deleted, akin to `rm -rf directory`, which could lead to loss of
  data if mistakes are made. This command will also delete any temporary
  filenames given to it.

  It is advised to use |ale#engine#ManageFile()| instead for deleting single
  files.


ale#fix#registry#Add(name, func, filetypes, desc, [aliases])
                                                       *ale#fix#registry#Add()*

  Given a |String| `name` for a name to add to the registry, a |String| `func`
  for a function name, a |List| `filetypes` for a list of filetypes to
  set for suggestions, and a |String| `desc` for a short description of
  the fixer, register a fixer in the registry.

  The `name` can then be used for |g:ale_fixers| in place of the function
  name, and suggested for fixing files.

  An optional |List| of |String|s for aliases can be passed as the `aliases`
  argument. These aliases can also be used for looking up a fixer function.
  ALE will search for fixers in the registry first by `name`, then by their
  `aliases`.


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, unless the linter is an
                         LSP linter. In which case, this argument must not be
                         defined, as LSP linters handle diangostics
                         automatically. See |ale-lsp-linters|.

                         The keys for each item in the List will be handled in
                         the following manner:
                                                           *ale-loclist-format*
                         `text` - This error message is required.
                         `lnum` - The line number is required. Any strings
                           will be automatically converted to numbers by
                           using `str2nr()`.

                           Line 0 will be moved to line 1, and lines beyond
                           the end of the file will be moved to the end.
                         `col` - The column number is optional and will
                           default to `0`. Any strings will be automatically
                           converted to number using `str2nr()`.
                         `end_col` - An optional end column number.
                           This key can be set to specify the column problems
                           end on, for improved highlighting.
                         `end_lnum` - An optional end line number.
                           This key can set along with `end_col` for
                           highlighting multi-line problems.
                         `bufnr` - This key represents the buffer number the
                           problems are for. This value will default to
                           the buffer number being checked.

                           The `filename` key can be set instead of this key,
                           and then the eventual `bufnr` value in the final
                           list will either represent the number for an open
                           buffer or `-1` for a file not open in any buffer.
                         `filename` - An optional filename for the file the
                           problems are for. This should be an absolute path to
                           a file.

                           Problems for files which have not yet been opened
                           will be set in those files after they are opened
                           and have been checked at least once.

                           Temporary files in directories used for Vim
                           temporary files with `tempname()` will be asssumed
                           to be the buffer being checked, unless the `bufnr`
                           key is also set with a valid number for some other
                           buffer.
                         `vcol` - Defaults to `0`.

                           If set to `1`, ALE will convert virtual column
                           positions for `col` and `end_col` to byte column
                           positions. If the buffer is changed in-between
                           checking it and displaying the results, the
                           calculated byte column positions will probably be
                           wrong.
                         `type` - Defaults to `'E'`.
                         `nr` - Defaults to `-1`.

  `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`.

  `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.

                         If an empty string is returned from the callback,
                         no jobs for linting will be run for that linter.
                         This can be used for skipping a linter call,
                         say if no configuration file was found.

                                                            *ale-command-chain*
  `command_chain`          A |List| of |Dictionary| items defining a series
                         of commands to be run. At least one |Dictionary|
                         should be provided. Each Dictionary must contain the
                         key `callback`, defining a |String| or |Funcref| for
                         a function returning a |String| for a command to run.

                         The callback functions for each command after the
                         first command in in the chain should accept two
                         arguments `(buffer, output)`, a buffer number and a
                         |List| of lines of output from the previous command
                         in the chain.

                         The first callback function in a chain accepts only
                         a `(buffer)` argument, as there are no previous
                         commands to run which return `output`.

                         If an empty string is returned for a command in a
                         chain, that command in the chain will be skipped,
                         and the next function in the chain will be called
                         immediately instead. If the last command in a chain
                         returns an empty string, then no linting will be
                         performed.

                         Commands in the chain will all use the
                         `output_stream` value provided in the root
                         |Dictionary|. Each command in the chain can also
                         provide an `output_stream` key to override this value.
                         See the `output_stream` description for more
                         information.

                         Commands in the chain all behave as if `read_buffer`
                         is set to `0` by default, except for the last command
                         in the chain, which uses the value set for
                         `read_buffer` in the root |Dictionary|. Each command
                         in the chain can also provide a `read_buffer` key
                         to override these values.
                         See the `read_buffer` description for more
                         information.

  `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.

  `read_buffer`            A |Number| (`0` or `1`) indicating whether a command
                         should read the Vim buffer as input via stdin. This
                         option is set to `1` by default, and can be disabled
                         if a command manually reads from a temporary file
                         instead, etc.

                                                                *ale-lint-file*
  `lint_file`              A |Number| (`0` or `1`) indicating whether a command
                         should read the file instead of the Vim buffer. This
                         option can be used for linters which must check the
                         file on disk, and which cannot check a Vim buffer
                         instead.

                         Linters set with this option will not be run as a
                         user types, per |g:ale_lint_on_text_changed|. Linters
                         will instead be run only when events occur against
                         the file on disk, including |g:ale_lint_on_enter|
                         and |g:ale_lint_on_save|. Linters with this option
                         set to `1` will also be run when linters are run
                         manually, per |ALELintPost-autocmd|.

                         When this option is set to `1`, `read_buffer` will
                         be set automatically to `0`. The two options cannot
                         be used together.

                                                              *ale-lsp-linters*
  `lsp`                    A |String| for defining LSP (Language Server Protocol)
                         linters.

                         This argument may be omitted or `''` when a linter
                         does not represent an LSP linter.

                         When this argument is set to `'stdio'`, then the
                         linter will be defined as an LSP linter which keeps a
                         process for a language server runnning, and
                         communicates with it directly via a |channel|.

                         When this argument is not empty, only one of either
                         `language` or `language_callback` must be defined,
                         and `project_root_callback` must be defined.

                         LSP linters handle diagnostics automatically, so
                         the `callback` argument must not be defined.

                         An optional `completion_filter` callback may be
                         defined for filtering completion results.

                         An optional `initialization_options` or
                         `initialization_options_callback` may be defined to
                         pass initialization options to the LSP.

  `project_root_callback`  A |String| or |Funcref| for a callback function
                         accepting a buffer number. A |String| should be
                         returned representing the path to the project for the
                         file being checked with the language server. If an
                         empty string is returned, the file will not be
                         checked at all.

                         This argument must only be set if the `lsp` argument
                         is also set to a non-empty string.

  `language`               A |String| representing the name of the language
                         being checked. This string will be sent to the LSP to
                         tell it what type of language is being checked.

                         This argument must only be set if the `lsp` argument
                         is also set to a non-empty string.

  `language_callback`      A |String| or |Funcref| for a callback function
                         accepting a buffer number. A |String| should be
                         returned representing the name of the language being
                         checked.

                         This option can be used instead of `language` if a
                         linter can check multiple languages.

  `completion_filter`      A |String| or |Funcref| for a callback function
                         accepting a buffer number and a completion item.

                         The completion item will be a |Dictionary| following
                         the Language Server Protocol `CompletionItem`
                         interface as described in the specification,
                         available online here:
                         https://microsoft.github.io/language-server-protocol

  `aliases`                A |List| of aliases for the linter name.

                         This argument can be set with alternative names for
                         selecting the linter with |g:ale_linters|. This
                         setting can make it easier to guess the linter name
                         by offering a few alternatives.

  `initialization_options` A |Dictionary| of initialization options for LSPs.
                         This will be fed (as JSON) to the LSP in the
                         initialize command.

  `initialization_options_callback`
                         A |String| or |Funcref| for a callback function
                         accepting a buffer number. A |Dictionary| should be
                         returned for initialization options to pass the LSP.
                         This can be used in place of `initialization_options`
                         when more complicated processing is needed.

  Only one of `command`, `command_callback`, or `command_chain` should be
  specified. `command_callback` is generally recommended when a command string
  needs to be generated dynamically, or any global options are used.
  `command_chain` is recommended where any system calls need to be made to
  retrieve some kind of information before running the final command.

  If temporary files or directories are created for commands run with
  `command_callback` or `command_chain`, then these tempoary files or
  directories can be managed by ALE, for automatic deletion.
  See |ale#engine#ManageFile()| and |ale#engine#ManageDirectory| for more
  information.

                                                   *ale-command-format-strings*

  All command strings will be formatted for special character sequences.
  Any substring `%s` will be replaced with the full path to the current file
  being edited. This format option can be used to pass the exact filename
  being edited to a program.

  For example: >
  'command': 'eslint -f unix --stdin --stdin-filename %s'
<
  Any substring `%t` will be replaced with a path to a temporary file. Merely
  adding `%t` will cause ALE to create a temporary file containing the
  contents of the buffer being checked. All occurrences of `%t` in command
  strings will reference the one temporary file. The temporary file will be
  created inside a temporary directory, and the entire temporary directory
  will be automatically deleted, following the behaviour of
  |ale#engine#ManageDirectory|. This option can be used for some linters which
  do not support reading from stdin.

  For example: >
  'command': 'ghc -fno-code -v0 %t',
<
  The character sequence `%%` can be used to emit a literal `%` into a
  command, so literal character sequences `%s` and `%t` can be escaped by
  using `%%s` and `%%t` instead, etc.

  If a callback for a command generates part of a command string which might
  possibly contain `%%`, `%s`, or `%t` where the special formatting behaviour
  is not desired, the |ale#engine#EscapeCommandPart()| function can be used to
  replace those characters to avoid formatting issues.

                                                  *ale-linter-loading-behavior*
                                                 *ale-linter-loading-behaviour*

  Linters for ALE will be loaded by searching |runtimepath| in the following
  format: >

  ale_linters/<filetype>/<linter_name>.vim
<
  Any linters which exist anywhere in |runtimepath| with that directory
  structure will be automatically loaded for the matching |filetype|. Filetypes
  containing `.` characters will be split into individual parts, and files
  will be loaded for each filetype between the `.` characters.

  Linters can be defined from vimrc and other files as long as this function
  is loaded first. For example, the following code will define a Hello World
  linter in vimrc in Vim 8: >

  " Plugins have to be loaded first.
  " If you are using a plugin manager, run that first.
  packloadall

  call ale#linter#Define('vim', {
  \   'name': 'echo-test',
  \   'executable': 'echo',
  \   'command': 'echo hello world',
  \   'callback': {buffer, lines -> map(lines, '{"text": v:val, "lnum": 1}')},
  \})
<

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-separated 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-separated filetypes are broken up into their
  components.


ale#linter#PreventLoading(filetype)               *ale#linter#PreventLoading()*

  Given a `filetype`, prevent any more linters from being loaded from
  |runtimepath| for that filetype. This function can be called from vimrc or
  similar to prevent ALE from loading linters.


ale#statusline#Count(buffer)                           *ale#statusline#Count()*

  Given the number of a buffer which may have problems, return a |Dictionary|
  containing information about the number of problems detected by ALE. The
  following keys are supported:

  `error`         -> The number of problems with type `E` and `sub_type != 'style'`
  `warning`       -> The number of problems with type `W` and `sub_type != 'style'`
  `info`          -> The number of problems with type `I`
  `style_error`   -> The number of problems with type `E` and `sub_type == 'style'`
  `style_warning` -> The number of problems with type `W` and `sub_type == 'style'`
  `total`         -> The total number of problems.


b:ale_linted                                                     *b:ale_linted*

  `b:ale_linted` is set to the number of times a buffer has been checked by
  ALE after all linters for one lint cycle have finished checking a buffer.
  This variable may not be defined until ALE first checks a buffer, so it
  should be accessed with |get()| or |getbufvar()|. For example: >

    " Print a message indicating how many times ALE has checked this buffer.
    echo 'ALE has checked this buffer ' . get(b:, 'ale_linted') . ' time(s).'
    " Print 'checked' using getbufvar() if a buffer has been checked.
    echo getbufvar(bufnr(''), 'ale_linted', 0) > 0 ? 'checked' : 'not checked'
<

ALELintPre                                                 *ALELintPre-autocmd*
ALELintPost                                               *ALELintPost-autocmd*
ALEFixPre                                                   *ALEFixPre-autocmd*
ALEFixPost                                                 *ALEFixPost-autocmd*

  These |User| autocommands are triggered before and after every lint or fix
  cycle. They can be used to update statuslines, send notifications, etc.
  The autocmd commands are run with |:silent|, so |:unsilent| is required for
  echoing messges.

  For example to change the color of the statusline while the linter is
  running:
>
    augroup ALEProgress
        autocmd!
        autocmd User ALELintPre  hi Statusline ctermfg=darkgrey
        autocmd User ALELintPOST hi Statusline ctermfg=NONE
    augroup end
<
  Or to display the progress in the statusline:
>
    let s:ale_running = 0
    let l:stl .= '%{s:ale_running ? "[linting]" : ""}'
    augroup ALEProgress
        autocmd!
        autocmd User ALELintPre  let s:ale_running = 1 | redrawstatus
        autocmd User ALELintPost let s:ale_running = 0 | redrawstatus
    augroup end

<
ALEJobStarted                                           *ALEJobStarted-autocmd*

  This |User| autocommand is triggered immediately after a job is successfully
  run. This provides better accuracy for checking linter status with
  |ale#engine#IsCheckingBuffer()| over |ALELintPre-autocmd|, which is actually
  triggered before any linters are executed.


===============================================================================
10. 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!

===============================================================================
11. 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:
