Undo most of the changes to eruby/ruby.

The new proprocess option is not useful here.

syntax_checkers/eruby/ruby.vim

@@ -15,34 +15,37 @@ if exists("g:loaded_syntastic_eruby_ruby_checker")
 endif
 let g:loaded_syntastic_eruby_ruby_checker=1
 
-if !exists("g:syntastic_erb_exec")
-    let g:syntastic_erb_exec = "erb"
-endif
-
 if !exists("g:syntastic_ruby_exec")
     let g:syntastic_ruby_exec = "ruby"
 endif
 
 function! SyntaxCheckers_eruby_ruby_IsAvailable()
-    return executable(expand(g:syntastic_erb_exec)) && executable(expand(g:syntastic_ruby_exec))
-endfunction
-
-function! SyntaxCheckers_eruby_ruby_Preprocess(errors)
-    let out = copy(a:errors)
-    for n in range(len(out))
-        let out[n] = substitute(out[n], '\V<%=', '<%', 'g')
-    endfor
-    return out
+    return executable(expand(g:syntastic_ruby_exec))
 endfunction
 
 function! SyntaxCheckers_eruby_ruby_GetLocList()
-    " TODO: do something about the encoding
-    let makeprg = syntastic#makeprg#build({
-        \ 'exe': expand(g:syntastic_erb_exec),
-        \ 'args': '-x -T -',
-        \ 'tail': ' | ' . expand(g:syntastic_ruby_exec) .  ' -c',
-        \ 'filetype': 'eruby',
-        \ 'subchecker': 'ruby' })
+    let exe = expand(g:syntastic_ruby_exec)
+    if !has('win32')
+        let exe = 'RUBYOPT= ' . exe
+    endif
+
+    let fname = "'" . escape(expand('%'), "\\'") . "'"
+
+    " TODO: encodings became useful in ruby 1.9 :)
+    if syntastic#util#versionIsAtLeast(syntastic#util#parseVersion('ruby --version'), [1, 9])
+        let enc = &fileencoding != '' ? &fileencoding : &encoding
+        let encoding_spec = ', :encoding => "' . (enc ==? 'utf-8' ? 'UTF-8' : 'BINARY') . '"'
+    else
+        let encoding_spec = ''
+    endif
+
+    "gsub fixes issue #7, rails has it's own eruby syntax
+    let makeprg =
+        \ exe . ' -rerb -e ' .
+        \ syntastic#util#shescape('puts ERB.new(File.read(' .
+        \     fname . encoding_spec .
+        \     ').gsub(''<%='',''<%''), nil, ''-'').src') .
+        \ ' | ' . exe . ' -c'
 
     let errorformat =
         \ '%-GSyntax OK,'.
@@ -54,7 +57,6 @@ function! SyntaxCheckers_eruby_ruby_GetLocList()
     return SyntasticMake({
         \ 'makeprg': makeprg,
         \ 'errorformat': errorformat,
-        \ 'preprocess': 'SyntaxCheckers_eruby_ruby_Preprocess',
         \ 'defaults': { 'bufnr': bufnr(""), 'vcol': 1 } })
 endfunction