Create reasonml merlin linter

copy @andreypopp 's ocaml merlin linter from this project into reason

README.md

@@ -95,6 +95,7 @@ name. That seems to be the fairest way to arrange this table.
 | Pug | [pug-lint](https://github.com/pugjs/pug-lint) |
 | Puppet | [puppet](https://puppet.com), [puppet-lint](https://puppet-lint.com) |
 | Python | [flake8](http://flake8.pycqa.org/en/latest/), [mypy](http://mypy-lang.org/), [pylint](https://www.pylint.org/) |
+| ReasonML | [merlin](https://github.com/the-lambda-church/merlin) see `:help ale-integration-reason-merlin` for configuration instructions
 | reStructuredText | [proselint](http://proselint.com/)|
 | RPM spec | [rpmlint](https://github.com/rpm-software-management/rpmlint) (disabled by default; see `:help ale-integration-spec`) |
 | Ruby | [reek](https://github.com/troessner/reek), [rubocop](https://github.com/bbatsov/rubocop), [ruby](https://www.ruby-lang.org) |

ale_linters/reason/merlin.vim

@@ -0,0 +1,17 @@
+" Author: Andrey Popp -- @andreypopp
+" Description: Report errors in ReasonML code with Merlin
+
+if !exists('g:merlin')
+    finish
+endif
+
+function! ale_linters#reason#merlin#Handle(buffer, lines) abort
+    return merlin#ErrorLocList()
+endfunction
+
+call ale#linter#Define('reason', {
+\   'name': 'merlin',
+\   'executable': 'ocamlmerlin',
+\   'command': 'true',
+\   'callback': 'ale_linters#reason#merlin#Handle',
+\})

doc/ale-reasonml.txt

@@ -0,0 +1,15 @@
+===============================================================================
+ALE ReasonML Integration                                       *ale-reasonml-options*
+
+
+-------------------------------------------------------------------------------
+merlin                                                       *ale-reasonml-merlin*
+
+  To use merlin linter for ReasonML source code you need to make sure Merlin for
+  Vim is correctly configured. See the corresponding Merlin wiki page for
+  detailed instructions
+  (https://github.com/the-lambda-church/merlin/wiki/vim-from-scratch).
+
+
+-------------------------------------------------------------------------------
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl: