#! /bin/sh 

# dgrep -- perform a delimeted grep 
# $Id: dgrep,v 1.1 1998/09/06 23:14:29 cdua Exp cdua $
# Carlos Duarte, 980722

USAGE="\
usage: $0 [-hn] -d delim pattern [files]

  -h      this help
  -d      specify delimeter to use (default: newline)
  -p      also print delimeter with matched record
  -r      simply dump all records

example: 
  dgrep -d '\n\n' word file 
    find word on a paragraph from file
    a paragraph is considered to be text, separated by one blank line
"

DOPRINT="s/@1@.*$//"
while : ; do
	case x"$1" in 
	x-h)	echo "$USAGE"; exit 1 ;;
	x-d)	shift; delim="$1" ;;
	x-p)	
		DOPRINT='
s/@2@.*$//
s/@1@//g'
		;;
	x-r)	DUMP='
i\
::::::::::
#' 	
		;;
	x--)	shift; break ;;
	x-?)	echo "invalid option -- `echo $1|cut -c2-`"
		echo "$USAGE"; exit 1 ;;
	*)	break ;;
	esac
	shift
done

# if _must_ accept one extra argument after options
if test $# -eq 0; then echo "$USAGE"; exit 1; fi

pattern="$1"
shift

: ${delim='\n'}
delim="`echo $delim | sed -e 's:/:\\\\/:g' -e 's/@/@@@/g'`"
pattern="`echo $pattern | sed -e 's:/:\\\\/:g' -e 's/@/@@@/g'`"

#echo "delim: $delim"
#echo "pattr: $pattern"
#exit

sed -n '
s/@/@@@/g
:chk_delm
/'"$delim"'/! {
	${
		/./!q
		s/$/@1@x@2@/
		b chk_pat
	}
	x
	n 
	s/@/@@@/g
	H
	x
	b chk_delm
}
s/'"$delim"'/@1@&@2@/
: chk_pat
'"$DUMP"' /^.*'"$pattern"'.*@1@/!b skip
h
# print delim?
# no:  s/@1@.*$//
# yes: s/@2@.*$//; s/@1@//g
'"$DOPRINT"'
s/@@@/@/g
p
x
:skip
s/^.*@2@//
b chk_delm
' "$@"

exit