diff --git a/runtime/syntax/haskell.vim b/runtime/syntax/haskell.vim
index e398085..1adb7ab 100644
--- a/runtime/syntax/haskell.vim
+++ b/runtime/syntax/haskell.vim
@@ -1,7 +1,7 @@
 " Vim syntax file
 " Language:		Haskell
 " Maintainer:		Haskell Cafe mailinglist <haskell-cafe@haskell.org>
-" Last Change:		2017 Jun 04
+" Last Change:		2017 Dec 16
 " Original Author:	John Williams <jrw@pobox.com>
 "
 " Thanks to Ryan Crumley for suggestions and John Meacham for
@@ -59,8 +59,8 @@
 syn region  hsString		start=+"+  skip=+\\\\\|\\"+  end=+"+  contains=hsSpecialChar
 syn match   hsCharacter		"[^a-zA-Z0-9_']'\([^\\]\|\\[^']\+\|\\'\)'"lc=1 contains=hsSpecialChar,hsSpecialCharError
 syn match   hsCharacter		"^'\([^\\]\|\\[^']\+\|\\'\)'" contains=hsSpecialChar,hsSpecialCharError
-syn match   hsNumber		"\<[0-9]\+\>\|\<0[xX][0-9a-fA-F]\+\>\|\<0[oO][0-7]\+\>"
-syn match   hsFloat		"\<[0-9]\+\.[0-9]\+\([eE][-+]\=[0-9]\+\)\=\>"
+syn match   hsNumber		"\v<[0-9]%(_*[0-9])*>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*>|<0[oO]_*%(_*[0-7])*>|<0[bB]_*[01]%(_*[01])*>"
+syn match   hsFloat		"\v<[0-9]%(_*[0-9])*\.[0-9]%(_*[0-9])*%(_*[eE][-+]?[0-9]%(_*[0-9])*)?>|<[0-9]%(_*[0-9])*_*[eE][-+]?[0-9]%(_*[0-9])*>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*\.[0-9a-fA-F]%(_*[0-9a-fA-F])*%(_*[pP][-+]?[0-9]%(_*[0-9])*)?>|<0[xX]_*[0-9a-fA-F]%(_*[0-9a-fA-F])*_*[pP][-+]?[0-9]%(_*[0-9])*>"
 
 " Keyword definitions. These must be patterns instead of keywords
 " because otherwise they would match as keywords at the start of a