regex - non-word characters vim -

I use the Vime Regex engine to highlight syntax highlighting, without having any word around it Trying, like:

  Does not match @ in @ matches.   
 I'm matching with either @ or I only match with the surrounding whitespace (which means that the line is not being matched at the beginning of the line. / P> 
 It seems as if the VIM does not really consider the standards in a very rigid manner, which is frustrating while writing syntax files.   
 
 
 I think regex in Vim is really powerful, even though syntax slightly awkward  
 provided in the form of an input:  
  @foo foo @ bar fu @fu @ bar   
 this Line: (leading by  /  (search)  
  / \ v (^ |) \ zs \ @ \ ze ($ |)   corresponds to  @  in the 1-3 line, but not the fourth row.  
 You  \ s  instead of  Space .