I am just beginning to fiddle around with semantic, for the purpose of writing a language translator.  I have not found out how to define multi-character operators, such as ++, += etc.  Trying to pick that up from the java.bnf file seems to reveal there is no support for multi-character operators on the token level. 

Also the regexp for postfix operators in the bnf definition was given as "[-+][-+]", which would mean "-+" and "+-" are also accepted as postfix operators (line 628 of java.bnf).

What is the right way to define multi-character operator tokens?