#!/bin/sh

# Make a tags file for Fortran routines.

info() {
	cat <<-END
	Use: `basename $0` [-m] [-_] file...

	Purpose: create a tags file for Fortran files.

	Restrictions: the Fortran word "function" or "subroutine"
	must be space- or tab-delimited on the left, and appear on the
	same line as the routine name.

	Options:
	-m	merge into existing tags file (default is to replace it).
	-_	For all routines "xxx_", make a duplicate entry "xxx".
	END

}

case $# in
0 ) info ; exit ;;
esac

merge=no
strip=no
for opt in "$@"
do
    case "$opt" in
    -m ) merge=yes ; shift ;;
    -h ) info ; exit 0 ;;
    -_ ) strip=yes ; shift ;;
    -* ) echo "`basename $0`: Invalid option $opt" ; exit 1 ;;
    * ) break ;;
    esac
done

if [ $merge = no -a -f tags ] ; then rm tags ; fi

for file in "$@"
do
    sed -n -e \
    '/^[ 	][ 	]*[Ss][Uu][Bb][Rr][Oo][Uu][Tt][Ii][Nn][Ee][ 	]*\([a-zA-Z_0-9]\)/ {s?.*?/^&$/?;h;s/.*[Ss][Uu][Bb][Rr][Oo][Uu][Tt][Ii][Nn][Ee][     ]*\([a-zA-Z_0-9][a-zA-Z_0-9]*\).*/\1/;G;s/\n/	@@@@@	/;p
}' \
    -e '/^[ 	][ 	]*[a-zA-Z_0-9*]*[ 	]*[Ff][Uu][Nn][Cc][Tt][Ii][Oo][Nn][ 	]*\([a-zA-Z_0-9]\)/ {s?.*?/^&$/?;h;s/.*[Ff][Uu][Nn][Cc][Tt][Ii][Oo][Nn][     ]*\([a-zA-Z_0-9][a-zA-Z_0-9]*\).*/\1/;G;s/\n/	@@@@@	/;p
}' \
    -e '/^[ 	][ 	]*[a-zA-Z_0-9*]*[ 	]*[a-zA-Z_0-9]*[ 	]*[Ff][Uu][Nn][Cc][Tt][Ii][Oo][Nn][ 	]*\([a-zA-Z_0-9]\)/ {s?.*?/^&$/?;h;s/.*[Ff][Uu][Nn][Cc][Tt][Ii][Oo][Nn][     ]*\([a-zA-Z_0-9][a-zA-Z_0-9]*\).*/\1/;G;s/\n/	@@@@@	/;p
}' \
    $file | sed "s
@@@@@
$file
" >> tags
done

f=/usr/tmp/tags.$$
sort tags > $f
case $strip in
yes )
    sed -n -e \
    'h;/^[a-zA-Z_0-9][a-zA-Z_0-9]*_[	]/s/\([a-zA-Z_0-9][a-zA-Z_0-9]*\)_[	]/\1	/p;g;p' $f >\
    tags
    ;;
* )
    cp $f tags
    ;;
esac
rm $f