#! /bin/sh
#
# newsyntax38 -- update a screenrc file from 3.3 to 3.8 syntax
#
# Please bring your scripts up to syntax level 3.3 before running this script.
# Please check all comments after running this script and watch out 
# for funny passages.
#
# * aka and shellaka are replaced by title and shelltitle.
# 
# * Pairs of termcap and terminfo commands are folded into a single 
#   termcapinfo command where possible.
#
# * trailing blanks are zapped. Unintentionally.
#
# 12.10.95, jnweiger, use at your own risk.
#
if [ $# != 1 ]; then
  echo "usage $0 screenrcfile"
  echo ""
  echo "The named file will be updated in place to the syntax of screen 3.8"
  echo "A backup copy will be written to <screenrcfile>.bak"
  exit 1;
fi

#Ultrix 4.2 /bin/sh does not handle "read a < $1" 
#Dean Gaudet <dgaudet@watdragon.uwaterloo.ca>
exec < $1
read a

if [ "$a" = "#3.8" ]; then
  echo "$1 already updated"
  exit 0
fi

rm -f $1.old $1.dups

cp $1 $1.old
echo "#3.8" > $1
echo "# Do not remove the above line. This screen rc file was updated" >> $1
echo "# by the newsyntax script." >> $1

# termcap and terminfo lines can only be folded when there is no parameter
# expansion in the codes. Parameters are denoted differently in 
# termcap and termcap syntax. Everything else is identical, I assume.
# Thus codes not containing '%' can be savely folded.

sed < $1.old > $1.dups \
-e 's/^\([	 #]*\)aka/\1title/' \
-e 's/^\([	 #]*\)shellaka/\1shelltitle/' \
-e 's/^\([	 #]*\)termcap[	 ][	 ]*\([^%]*$\)/\1termcapinfo \2/' \
-e 's/^\([	 #]*\)terminfo[	 ][	 ]*\([^%]*$\)/\1termcapinfo \2/' \
-e 's/\\/\\\\/g'

# Oh, my bourne shell seems to gobble backslashes while reading.
# Thus the sed above duplicates them in advance. 
# Hope this is not just another silly bash featureism.
# It still zaps trailing blanks. I do not know why. But that is nice.

exec < $1.dups
while read a ; do
  if [ "$a" = "$b" ]; then
    case "$a" in
      *termcapinfo*) continue ;;
    esac
  fi
  echo "$a" >> $1
  b="$a"
done

rm -f $1.dups