GROUP                        GROUP pattern

    GROUP re { action }
    GROUP re { action }
    GROUP re { action }
    GROUP re { action }

    or

    GROUP re
    GROUP re { action }
    GROUP re
    GROUP re { action }

    or

    GROUP re
    GROUP re { action }
    GROUP re
    GROUP re

    The pattern associated with the GROUP pattern keyword may be a  regular
    expression, a string constant or a variable.  Thus, the following GROUP
    patterns are allowable:

    GROUP /regular expression constant/
    GROUP "string expression constant"
    GROUP defined_variable

    Strings are treated as regular expressions.  Variables are converted to
    their string values and treated as regular expressions.  The conversion
    of  variables  is  done  only  once  when  the GROUP patterns are first
    utilized to scan an input record.

    All consecutive GROUP/action pairs are  grouped and the search for  the
    regular expressions optimized over the GROUP.  Each regular  expression
    of the GROUP may  have a separate action  associated with it.   In this
    case the appropriate  action is executed  if the regular  expression is
    matched on  the current  input record.   If  the action  for a  regular
    expression  is  not  given,  then  the  next action explicitly given is
    executed.  If no action is  given for the last regular expression  of a
    GROUP, then the default action

                                  { print ; }

    is assigned to it.  When one of the regular expressions of the GROUP is
    matched, the built-in variable, NG, is  set equal to the number of  the
    expression.  The numbering of the expressions in the GROUP starts  with
    one, 1.

    There may be more than one  GROUP of regular expression patterns.   Any
    pattern not preceded with  the GROUP keyword will  cause a GROUP to  be
    terminated.  The occurrence of the GROUP keyword again will start a new
    GROUP and the numbering of the new group starts over at one, 1.