code: protected boolean ignore(VDMToken tok) throws LexException
  	{
  		if (lastToken().is(tok))
  		{
  			nextToken();
  			return true;
  		} else
  		{
  			return false;
  		}
  	}
docs: If the last token is the one passed, advance by one, else do nothing.
  
  @param tok
  The token type to check for.
  @return True if the token was skipped.
  @throws LexException