lib/rouge/lexers/prolog.rb in rouge-1.9.0 vs lib/rouge/lexers/prolog.rb in rouge-1.9.1

@@ -28,10 +28,10 @@
         rule /\d+\.\d+/, Num::Float
         rule /\d+/, Num
       end
 
       state :atoms do
-        rule /[[:lower:]]([_[:lower:][:digit:]])*/, Str::Symbol
+        rule /[[:lower:]]([_[:word:][:digit:]])*/, Str::Symbol
         rule /'[^']*'/, Str::Symbol
       end
 
       state :operators do
         rule /(<|>|=<|>=|==|=:=|=|\/|\/\/|\*|\+|-)(?=\s|[a-zA-Z0-9\[])/,