semantic-lex-open-paren

semantic-lex-open-paren is a variable defined in `lex.el'.
Its value is

((looking-at "\\s(")
 (setq semantic-lex-current-depth
       (1+ semantic-lex-current-depth))
 (semantic-lex-push-token
  (semantic-lex-token 'open-paren
		      (match-beginning 0)
		      (match-end 0))))

Documentation:
Detect and create an open parenthesis token.