Add turtle check via ttl

turtle in an RDF syntax defined by the W3C
https://www.w3.org/TR/turtle/

ttl is a nodejs turtle validation tool:
https://www.npmjs.com/package/turtle-validator

syntax_checkers/turtle/ttl.vim

@@ -0,0 +1,40 @@
+"============================================================================
+"File:        ttl.vim
+"Description: turtle syntax checker - using ttl from turtle-validator (npm)
+"Maintainer:  Antoine Reilles (tonio@NetBSD.org)
+"License:     This program is free software. It comes without any warranty,
+"             to the extent permitted by applicable law. You can redistribute
+"             it and/or modify it under the terms of the Do What The Fuck You
+"             Want To Public License, Version 2, as published by Sam Hocevar.
+"             See http://sam.zoy.org/wtfpl/COPYING for more details.
+"============================================================================
+
+if exists('g:loaded_syntastic_turtle_ttl_checker')
+    finish
+endif
+let g:loaded_syntastic_turtle_ttl_checker = 1
+
+let s:save_cpo = &cpo
+set cpo&vim
+
+function! SyntaxCheckers_turtle_ttl_GetLocList() dict
+    let makeprg = self.makeprgBuild({ 'post_args_after': '' })
+
+    let errorformat =
+        \ '%E[Error: %m at line %l.],' .
+        \ '%E[Error: %m on line %l.]'
+
+    return SyntasticMake({
+        \ 'makeprg': makeprg,
+        \ 'errorformat': errorformat,
+        \ 'defaults': {'bufnr': bufnr('')} })
+endfunction
+
+call g:SyntasticRegistry.CreateAndRegisterChecker({
+    \ 'filetype': 'turtle',
+    \ 'name': 'ttl'})
+
+let &cpo = s:save_cpo
+unlet s:save_cpo
+
+" vim: set sw=4 sts=4 et fdm=marker: