Update

syntax/ecrystal.vim

@@ -0,0 +1,37 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'crystal') == -1
+
+if &syntax !~# '\<ecrystal\>' || get(b:, 'current_syntax') =~# '\<ecrystal\>'
+  finish
+endif
+
+if !exists('main_syntax')
+  let main_syntax = 'ecrystal'
+endif
+
+call ecrystal#SetSubtype()
+
+if b:ecrystal_subtype !=# ''
+  exec 'runtime! syntax/'.b:ecrystal_subtype.'.vim'
+  unlet! b:current_syntax
+endif
+
+syn include @crystalTop syntax/crystal.vim
+
+syn cluster ecrystalRegions contains=ecrystalControl,ecrystalRender,ecrystalComment
+
+syn region ecrystalControl matchgroup=ecrystalDelimiter start="<%%\@!-\="  end="-\=%>" display contains=@crystalTop        containedin=ALLBUT,@ecrystalRegions
+syn region ecrystalRender  matchgroup=ecrystalDelimiter start="<%%\@!-\==" end="-\=%>" display contains=@crystalTop        containedin=ALLBUT,@ecrystalRegions
+syn region ecrystalComment matchgroup=ecrystalDelimiter start="<%%\@!-\=#" end="-\=%>" display contains=crystalTodo,@Spell containedin=ALLBUT,@ecrystalRegions
+
+" Define the default highlighting.
+
+hi def link ecrystalDelimiter PreProc
+hi def link ecrystalComment   crystalComment
+
+let b:current_syntax = 'ecrystal'
+
+if exists('main_syntax') && main_syntax ==# 'ecrystal'
+  unlet main_syntax
+endif
+
+endif