*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. Global Options.......................|ale-options| 4. Linter Options and Recommendations...|ale-linter-options| asm...................................|ale-asm-options| gcc.................................|ale-asm-gcc| c.....................................|ale-c-options| clang...............................|ale-c-clang| cppcheck............................|ale-c-cppcheck| gcc.................................|ale-c-gcc| chef..................................|ale-chef-options| foodcritic..........................|ale-chef-foodcritic| cpp...................................|ale-cpp-options| clang...............................|ale-cpp-clang| clangtidy...........................|ale-cpp-clangtidy| cppcheck............................|ale-cpp-cppcheck| gcc.................................|ale-cpp-gcc| css...................................|ale-css-options| stylelint...........................|ale-css-stylelint| cmake.................................|ale-cmake-options| cmakelint...........................|ale-cmake-cmakelint| erlang................................|ale-erlang-options| erlc................................|ale-erlang-erlc| fortran...............................|ale-fortran-options| gcc.................................|ale-fortran-gcc| go....................................|ale-go-options| gometalinter........................|ale-go-gometalinter| handlebars............................|ale-handlebars-options| ember-template-lint.................|ale-handlebars-embertemplatelint| html..................................|ale-html-options| htmlhint............................|ale-html-htmlhint| tidy................................|ale-html-tidy| java..................................|ale-java-options| checkstyle..........................|ale-java-checkstyle| javac...............................|ale-java-javac| javascript............................|ale-javascript-options| eslint..............................|ale-javascript-eslint| flow................................|ale-javascript-flow| jshint..............................|ale-javascript-jshint| standard............................|ale-javascript-standard| xo..................................|ale-javascript-xo| kotlin................................|ale-kotlin-options| kotlinc.............................|ale-kotlin-kotlinc| lua...................................|ale-lua-options| luacheck............................|ale-lua-luacheck| ocaml.................................|ale-ocaml-options| merlin..............................|ale-ocaml-merlin| perl..................................|ale-perl-options| perl................................|ale-perl-perl| php...................................|ale-php-options| phpcs...............................|ale-php-phpcs| phpmd...............................|ale-php-phpmd| python................................|ale-python-options| flake8..............................|ale-python-flake8| mypy................................|ale-python-mypy| pylint..............................|ale-python-pylint| ruby..................................|ale-ruby-options| reek................................|ale-ruby-reek| rubocop.............................|ale-ruby-rubocop| rust..................................|ale-rust-options| cargo...............................|ale-rust-cargo| rustc...............................|ale-rust-rustc| sass..................................|ale-sass-options| stylelint...........................|ale-sass-stylelint| scss..................................|ale-scss-options| stylelint...........................|ale-scss-stylelint| sh....................................|ale-sh-options| shell...............................|ale-sh-shell| shellcheck..........................|ale-sh-shellcheck| spec..................................|ale-spec-options| rpmlint.............................|ale-spec-rpmlint| tex...................................|ale-tex-options| chktex..............................|ale-tex-chktex| lacheck.............................|ale-tex-lacheck| typescript............................|ale-typescript-options| tslint..............................|ale-typescript-tslint| vim...................................|ale-vim-options| vint................................|ale-vim-vint| yaml..................................|ale-yaml-options| yamllint............................|ale-yaml-yamllint| 5. Commands/Keybinds....................|ale-commands| 6. API..................................|ale-api| 7. Special Thanks.......................|ale-special-thanks| 8. Contact..............................|ale-contact| =============================================================================== 1. Introduction *ale-introduction* ALE provides the means to run linters asynchronously in Vim in a variety of languages and tools. ALE sends the contents of buffers to linter programs using the |job-control| features available in Vim 8 and NeoVim. For Vim 8, Vim must be compiled with the |job| and |channel| and |timer| features as a minimum. ALE supports the following key features: 1. Running linters when text is changed. 2. Running linters when files are opened. 3. Running linters when files are saved. (When a global flag is set.) 4. Populating the |loclist| with warning and errors. 5. Setting |signs| with warnings and errors for error markers. 6. Using |echo| to show error messages when the cursor moves. =============================================================================== 2. Supported Languages & Tools *ale-support* The following languages and tools are supported. * ASM: 'gcc' * Ansible: 'ansible-lint' * Asciidoc: 'proselint' * Bash: 'shell' (-n flag), 'shellcheck' * Bourne Shell: 'shell' (-n flag), 'shellcheck' * C: 'cppcheck', 'gcc', 'clang' * C++ (filetype cpp): 'clang', 'clangtidy', 'cppcheck', 'gcc' * C#: 'mcs' * Chef: 'foodcritic' * CMake: 'cmakelint' * CoffeeScript: 'coffee', 'coffelint' * Crystal: 'crystal' * CSS: 'csslint', 'stylelint' * Cython (pyrex filetype): 'cython' * D: 'dmd' * Dockerfile: 'hadolint' * Elixir: 'credo', 'dogma' * Elm: 'elm-make' * Erlang: 'erlc' * Fortran: 'gcc' * Go: 'gofmt', 'go vet', 'golint', 'go build', 'gosimple', 'staticcheck' * Haml: 'hamllint' * Handlebars: 'ember-template-lint' * Haskell: 'ghc', 'hlint', 'hdevtools' * HTML: 'HTMLHint', 'proselint', 'tidy' * Java: 'javac' * JavaScript: 'eslint', 'jscs', 'jshint', 'flow', 'xo' * JSON: 'jsonlint' * Kotlin: 'kotlinc' * LaTeX (tex): 'chktex', 'lacheck', 'proselint' * Lua: 'luacheck' * Markdown: 'mdl', 'proselint', 'vale' * MATLAB: 'mlint' * nim: 'nim check' * nix: 'nix-instantiate' * nroff: 'proselint' * OCaml: 'merlin' (see |ale-linter-integration-ocaml-merlin|) * Perl: 'perl' (-c flag), 'perlcritic' * PHP: 'hack', 'php' (-l flag), 'phpcs', 'phpmd' * Pod: 'proselint' * Pug: 'pug-lint' * Puppet: 'puppet', 'puppet-lint' * Python: 'flake8', 'mypy', 'pylint' * ReasonML: 'merlin' * reStructuredText: 'proselint' * RPM spec: 'spec' * Rust: 'rustc' (see |ale-integration-rust|) * Ruby: 'reek', 'rubocop' * SASS: 'sasslint', 'stylelint' * SCSS: 'sasslint', 'scsslint', 'stylelint' * Scala: 'scalac' * Slim: 'slim-lint' * SML: 'smlnj' * SQL: 'sqlint' * Swift: 'swiftlint' * Texinfo: 'proselint' * Text: 'proselint', 'vale' * TypeScript: 'tslint', 'typecheck' * Verilog: 'iverilog', 'verilator' * Vim: 'vint' * Vim help: 'proselint' * XHTML: 'proselint' * YAML: 'yamllint' =============================================================================== 3. 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_echo_cursor *g:ale_echo_cursor* Type: |Number| Default: `1` When this option is set to `1`, a truncated message will be echoed when a cursor is near a warning or error. ALE will attempt to find the warning or error at a column nearest to the cursor when the cursor is resting on a line which contains a warning or error. This option can be set to `0` to disable this behaviour. The format of the message can be customizable in |g:ale_echo_msg_format|. g:ale_echo_msg_error_str *g:ale_echo_msg_error_str* Type: |String| Default: `Error` The string used for error severity in the echoed message. Note |`g:ale_echo_cursor`| should be set to 1 Note |`g:ale_echo_msg_format`| should contain the `%severity%` handler g:ale_echo_msg_format *g:ale_echo_msg_format* Type: |String| Default: `%s` This variable defines the format of the echoed message. The `%s` is the error message itself, and it can contain the following handlers: - `%linter%` for linter's name - `%severity%` for the type of severity Note |`g:ale_echo_cursor`| should be setted to 1 g:ale_echo_msg_warning_str *g:ale_echo_msg_warning_str* Type: |String| Default: `Warning` The string used for warning severity in the echoed message. Note |`g:ale_echo_cursor`| should be set to 1 Note |`g:ale_echo_msg_format`| should contain the `%severity%` handler g:ale_emit_conflict_warnings *g:ale_emit_conflict_warnings* Type: |Number| Default: `1` When set to `0`, ALE will not emit any warnings on startup about conflicting plugins. ALE will probably not work if other linting plugins are installed. g:ale_enabled *g: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. 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: `0` 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. ALE will likely consume a lot of memory if this option is on, so it should only be used for debugging problems with linters. g:ale_keep_list_window_open *g: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 quicfix windows will be closed automatically when there are no warnings or errors. See: |g:ale_open_list| 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 |BufEnter| and |BufRead| events will be used to apply linters when buffers are first opened. If this is not desired, this variable can be set to `0` in your vimrc file to disable this behaviour. g:ale_lint_on_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. 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` This option will make ALE run the linters whenever leaving insert mode when it it set to `1` in your vimrc file. 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: > { \ 'zsh': 'sh', \ 'csh': 'sh', \} < For example, if you wish to map a new filetype `'foobar'` to run the `'php'` linters, you could set the following: > let g:ale_linter_aliases = {'foobar': 'php'} < When combined with the |g:ale_linters| option, the original filetype (`'foobar'`) will be used for determining which linters to run, not the aliased type (`'php'`). This allows an aliased type to run a different set of linters from the type it is being mapped to. 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 filetepe. 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. 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. Only the filetypes specified in the dictionary will be limited in terms of which linters will be run. This |Dictionary| will be merged with a default dictionary containing the following values: > { \ 'csh': ['shell'], \ 'rust': ['cargo'], \ '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 available for a given filetype can be enabled by using the string `'all'`: > 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 a default Dictionary. 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_open_list *g:ale_open_list* Type: |Number| 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|) 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 until closed manually. g:ale_set_highlights *g:ale_set_highlights* Type: |Number| Default: `has('syntax')` When this option is set to `1`, highlights will be set in for erros and warnings. The `ALEError` and `ALEWarning` highlight groups will be used to provide highlights, and default to linking to `SpellBad` and `SpellCap` respectively by default. 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 warnings and errors which are found by ALE, instead of the |loclist|. The loclist will never be populated when this option is on. g:ale_set_signs *g:ale_set_signs* Type: |Number| Default: `has('signs')` When this option is set to `1`, the |sign| column will be populated with signs marking where errors and warnings appear in the file. The `ALEErrorSign` and `ALEWarningSign` highlight groups will be used to provide highlighting for the signs. The text used for signs can be customised with the |g:ale_sign_error| and |g:ale_sign_warning| options. The `ALEErrorSign` and `ALEWarningLine` highlight groups will be used to provide highlighting for the lines that the signs reside on. g:ale_sign_column_always *g:ale_sign_column_always* Type: |Number| Default: `0` By default, the sign gutter will disappear when all warnings and errors have been fixed for a file. When this option is set to `1`, the sign column will remain open. This can be preferable if you don't want the text in your file to move around as you edit a file. g:ale_sign_error *g:ale_sign_error* Type: |String| Default: `'>>'` This string can be changed to change the characters used for the sign gutter for lines which at least one error on them. Lines with both errors and warnings on them will show the error marker, as errors take precedence. g:ale_sign_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: `'--'` This string can be changed to change the characters used for the sign gutter for lines which at least one warning on them. g:ale_statusline_format *g:ale_statusline_format* Type: |List| Default: `['%d error(s)', '%d warning(s)', 'OK']` This variable defines the format of |`ale#statusline#status()`| output. - The 1st element is for errors - The 2nd element is for warnings - The 3rd element is for when no errors are detected g: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 in signs, the loclist, and echo messages, etc. If these errors are found to be too irritating while edits are being made, and you have configured Vim to automatically remove trailing whitespace, then you can disable these warnings for some linters by setting this option to `0`. Not all linters may respect this option. If a linter does not, please file a bug report, and it may be possible to add such support. This option may be configured on a per buffer basis. =============================================================================== 4. Linter Options and Recommendations *ale-linter-options* Linter options are documented in individual help files. See the table of contents at |ale-contents|. Every linter variable 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`. =============================================================================== 5. Commands/Keybinds *ale-commands* 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 `(ale_lint)` is defined for this command. ALEPrevious *ALEPrevious* ALEPreviousWrap *ALEPreviousWrap* ALENext *ALENext* ALENextWrap *ALENextWrap* *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. The following || mappings are defined for the commands: > (ale_previous) - ALEPrevious (ale_previous_wrap) - ALEPreviousWrap (ale_next) - ALENext (ale_next_wrap) - ALENextWrap < For example, these commands could be bound to the keys Ctrl + j and Ctrl + k: > " Map movement through errors without wrapping. nmap (ale_previous) nmap (ale_next) " OR map keys to use wrapping. nmap (ale_previous_wrap) nmap (ale_next_wrap) < ALEToggle *ALEToggle* ALEEnable *ALEEnable* ALEDisable *ALEDisable* Enable or disable ALE, including all of its autocmd events, loclist items, quickfix items, signs, current jobs, etc. Calling this option will change the |g:ale_enabled| variable. ALEDetail *ALEDetail* Show the full linter message for the current line. This will only have an effect on lines that contain a linter message. A plug mapping `(ale_detail)` is defined for this command. =============================================================================== 6. API *ale-api* ale#Queue(delay, [linting_flag]) *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. 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 rerurn the list of warnings and errors reported by ALE for a given buffer in the format accepted by |setqflist()|. 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#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. The keys for each item in the List will be handled in the following manner: `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 coverted to number using `str2nr()`. `bufnr` - The buffer number should match the buffer being checked, and this value will default to the buffer being checked. `vcol` - Defaults to `0`. `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 |ALELint-autocmd|. When this option is set to `1`, `read_buffer` will be set automatically to `0`. The two options cannot be used together. 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-behaviour* Linters for ALE will be loaded by searching |runtimepath| in the following format: > ale_linters//.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. ale#linter#Get(filetype) *ale#linter#Get()* Return all of linters configured for a given filetype as a |List| of |Dictionary| values in the format specified by |ale#linter#Define()|. Filetypes may be dot-seperated to invoke linters for multiple filetypes: for instance, the filetype `javascript.jsx` will return linters for both the `javascript` and `jsx` filetype. Aliases may be defined in as described in |g:ale_linter_aliases|. Aliases are applied after dot-seperated filetypes are broken up into their components. ale#statusline#Status() *ale#statusline#Status()* Return a formatted string that can be added to the statusline. The output's format is defined in |`g:ale_statusline_format`|. To enable it, the following should be present in your |statusline| settings: > %{ale#statusline#Status()} ALELint *ALELint-autocmd* This |User| autocommand is triggered by ALE every time it completes a lint cycle. It can be used to update statuslines, send notifications, or complete any other operation that needs to be done after linting has been performed. For example, you can echo a message when linting is complete like so: > autocmd User ALELint echom "ALE run!" < =============================================================================== 7. 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! =============================================================================== 8. 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: