Add Perl6 support via 'perl6 -c'

doc/ale-perl6.txt

@@ -0,0 +1,43 @@
+===============================================================================
+ALE Perl6 Integration                                       *ale-perl6-options*
+
+Checking code with `perl6` is disabled by default, as `perl6` code cannot be
+checked without executing it. Specifically, we use the `-c` flag to see if
+`perl6` code compiles. This does not execute all of the code in a file, but it
+does run `BEGIN` and `CHECK` blocks. See `perl6 --help`
+
+Full support requires a perl6 implementation that supports the
+PERL6_EXCEPTIONS_HANDLER environment variable and JSON error output,
+which was specified in 6.d. Rakudo version 2018.08 is the first rakudo release
+that supports this. See `perl6 --version` and
+https://docs.perl6.org/programs/03-environment-variables.
+
+Without this variable, errors and warnings will appear at line 1, and can be
+viewed with ALEDetail. This also serves as a fallback for errors and warnings
+that do not trigger JSON output.
+
+See |g:ale_linters|.
+
+
+===============================================================================
+perl6                                                         *ale-perl6-perl6*
+
+g:ale_perl6_perl6_executable                     *g:ale_perl6_perl6_executable*
+                                                 *b:ale_perl6_perl6_executable*
+  Type: |String|
+  Default: `'perl6'`
+
+  This variable can be changed to modify the executable used for linting
+  perl6.
+
+
+g:ale_perl6_perl6_options                           *g:ale_perl6_perl6_options*
+                                                    *b:ale_perl6_perl6_options*
+  Type: |String|
+  Default: `'-c -Ilib'`
+
+  This variable can be changed to alter the command-line arguments to the
+  perl6 invocation.
+
+===============================================================================
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale.txt

@@ -203,6 +203,8 @@ CONTENTS                                                         *ale-contents*
       perl................................|ale-perl-perl|
       perlcritic..........................|ale-perl-perlcritic|
       perltidy............................|ale-perl-perltidy|
+    perl6.................................|ale-perl6-options|
+      perl6...............................|ale-perl6-perl6|
     php...................................|ale-php-options|
       langserver..........................|ale-php-langserver|
       phan................................|ale-php-phan|
@@ -438,6 +440,7 @@ Notes:
 * OCaml: `merlin` (see |ale-ocaml-merlin|), `ols`, `ocamlformat`
 * Pawn: `uncrustify`
 * Perl: `perl -c`, `perl-critic`, `perltidy`
+* Perl6: `perl6 -c`
 * PHP: `langserver`, `phan`, `php -l`, `phpcs`, `phpmd`, `phpstan`, `phpcbf`, `php-cs-fixer`, `psalm`!!
 * PO: `alex`!!, `msgfmt`, `proselint`, `write-good`
 * Pod: `alex`!!, `proselint`, `write-good`
@@ -1306,6 +1309,7 @@ g:ale_linters                                                   *g:ale_linters*
   \   'hack': ['hack'],
   \   'help': [],
   \   'perl': ['perlcritic'],
+  \   'perl6': [],
   \   'python': ['flake8', 'mypy', 'pylint'],
   \   'rust': ['cargo'],
   \   'spec': [],