Simplify ruby*Constant syntax group matching

Author: dkearns

syntax/ruby.vim

@@ -92,7 +92,7 @@ syn match rubyFloat	"\%(\%(\w\|[]})\"']\s*\)\@<!-\)\=\<\%(0\|[1-9]\d*\%(_\d\+\)*
 syn match rubyLocalVariableOrMethod "\<[_[:lower:]][_[:alnum:]]*[?!=]\=" contains=NONE display transparent
 syn match rubyBlockArgument	    "&[_[:lower:]][_[:alnum:]]"		 contains=NONE display transparent
 
-syn match  rubyConstant		"\%(\%([.@$]\@<!\.\)\@<!\<\|::\)\_s*\zs\u\w*\%(\>\|::\)\@=\%(\s*(\)\@!"
+syn match  rubyConstant		"\%(\%(^\|[^.]\)\.\_s*\)\@<!\<\u\w*\>\%(\s*(\)\@!"
 syn match  rubyClassVariable	"@@\%(\h\|[^\x00-\x7F]\)\%(\w\|[^\x00-\x7F]\)*" display
 syn match  rubyInstanceVariable "@\%(\h\|[^\x00-\x7F]\)\%(\w\|[^\x00-\x7F]\)*"  display
 syn match  rubyGlobalVariable	"$\%(\%(\h\|[^\x00-\x7F]\)\%(\w\|[^\x00-\x7F]\)*\|-.\)"
@@ -117,10 +117,8 @@ syn match rubyPredefinedVariable "$_\>"											   display
 syn match rubyPredefinedVariable "$-[0FIKadilpvw]\>"									   display
 syn match rubyPredefinedVariable "$\%(deferr\|defout\|stderr\|stdin\|stdout\)\>"					   display
 syn match rubyPredefinedVariable "$\%(DEBUG\|FILENAME\|KCODE\|LOADED_FEATURES\|LOAD_PATH\|PROGRAM_NAME\|SAFE\|VERBOSE\)\>" display
-syn match rubyPredefinedConstant "\%(\%(\.\@<!\.\)\@<!\|::\)\_s*\zs\%(MatchingData\|ARGF\|ARGV\|ENV\)\>\%(\s*(\)\@!"
-syn match rubyPredefinedConstant "\%(\%(\.\@<!\.\)\@<!\|::\)\_s*\zs\%(DATA\|FALSE\|NIL\)\>\%(\s*(\)\@!"
-syn match rubyPredefinedConstant "\%(\%(\.\@<!\.\)\@<!\|::\)\_s*\zs\%(STDERR\|STDIN\|STDOUT\|TOPLEVEL_BINDING\|TRUE\)\>\%(\s*(\)\@!"
-syn match rubyPredefinedConstant "\%(\%(\.\@<!\.\)\@<!\|::\)\_s*\zs\%(RUBY_\%(VERSION\|RELEASE_DATE\|PLATFORM\|PATCHLEVEL\|REVISION\|DESCRIPTION\|COPYRIGHT\|ENGINE\)\)\>\%(\s*(\)\@!"
+syn match rubyPredefinedConstant "\%(\%(^\|[^.]\)\.\_s*\)\@<!\<\%(ARGF\|ARGV\|ENV\|DATA\|FALSE\|NIL\|STDERR\|STDIN\|STDOUT\|TOPLEVEL_BINDING\|TRUE\)\>\%(\s*(\)\@!"
+syn match rubyPredefinedConstant "\%(\%(^\|[^.]\)\.\_s*\)\@<!\<\%(RUBY_\%(VERSION\|RELEASE_DATE\|PLATFORM\|PATCHLEVEL\|REVISION\|DESCRIPTION\|COPYRIGHT\|ENGINE\)\)\>\%(\s*(\)\@!"
 
 " Normal Regular Expression
 syn region rubyRegexp matchgroup=rubyRegexpDelimiter start="\%(\%(^\|\<\%(and\|or\|while\|until\|unless\|if\|elsif\|when\|not\|then\|else\)\|[;\~=!|&(,[<>?:*+-]\)\s*\)\@<=/" end="/[iomxneus]*" skip="\\\\\|\\/" contains=@rubyRegexpSpecial fold