Add elm support, closes #81

ftplugin/elm.vim

@@ -0,0 +1,86 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'elm') == -1
+  
+" elm.vim - Plugin for the Elm programming language
+" Maintainer:   Alexander Noriega <http://lambdatoast.com/>
+" Version:      0.4.3
+
+" Plugin setup stuff
+
+if exists("b:did_ftplugin")
+  finish
+endif
+
+let b:did_ftplugin = 1
+
+" Compilation
+
+function! ElmMake(file)
+  let args = a:file
+  return elm#io#system("elm-make", args)
+endfunction
+
+function! ElmMakeCurrentFile()
+  echo ElmMake(expand("%"))
+endfunction
+
+function! ElmMakeMain()
+  echo ElmMake("Main.elm")
+endfunction
+
+function! ElmMakeFile(file)
+  echo ElmMake(a:file)
+endfunction
+
+" REPL
+
+function! ElmRepl()
+  !elm-repl
+endfunction
+
+" Evaluation
+
+function! ElmEvalLine()
+  return ElmEval(getline("."))
+endfunction
+
+function! ElmEvalSelection()
+  let savedReg = @z
+  normal! `<v`>"zy
+  let res = ElmEval(substitute(getreg("z"), "\n", "\\\n", "g"))
+  let @z = savedReg
+  normal! gv
+endfunction
+
+function! ElmEval(sourceCode)
+  let currentLine = a:sourceCode
+  let args = "echo '" . currentLine . "' | elm-repl"
+  let result = elm#io#system("echo", args)
+  let cleanResult = "-- " . join(s:Filtered(function("s:IsUsefulReplOutput"), split(result, "\n")), "")
+  put =cleanResult
+endfunction
+
+function! s:IsUsefulReplOutput(str)
+  return a:str !~ "^Elm REPL" && a:str !~ "Type :help" && a:str !~ ">\\s*$"
+endfunction
+
+" List processing
+
+function! s:Filtered(fn, l)
+    let new_list = deepcopy(a:l)
+    call filter(new_list, string(a:fn) . '(v:val)')
+    return new_list
+endfunction
+
+command -buffer ElmEvalLine          call ElmEvalLine()
+command -buffer ElmEvalSelection     call ElmEvalSelection()
+command -buffer ElmMakeMain          call ElmMakeMain()
+command -buffer -nargs=1 ElmMakeFile call ElmMakeFile <args>
+command -buffer ElmMakeCurrentFile   call ElmMakeCurrentFile()
+command -buffer ElmRepl              call ElmRepl()
+
+" Define comment convention
+
+setlocal comments=:--
+setlocal commentstring=--%s
+
+endif