PATCH: narrow-to-region

[Peter Stephenson <pws@xxxxxxx>]

Here is a tidied up version of narrow-to-region together with a simple
widget narrow-to-region-invisible which reduces text outside the region
to `...'.

Index: Doc/Zsh/contrib.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/contrib.yo,v
retrieving revision 1.19
diff -u -r1.19 contrib.yo
--- Doc/Zsh/contrib.yo	21 Mar 2002 23:03:14 -0000	1.19
+++ Doc/Zsh/contrib.yo	4 Jul 2002 13:24:46 -0000
@@ -475,6 +475,40 @@
 
 example(bindkey '^Xf' insert-files)
 )
+tindex(narrow-to-region)
+tindex(narrow-to-region-invisible)
+xitem(tt(narrow-to-region [ -p) var(pre) tt(] [ -P) var(post) tt(] [ -n ] [) var(start) var(end) tt(]))
+item(tt(narrow-to-region-invisible))(
+Narrow the editable portion of the buffer to the region between the cursor
+and the mark, which may be in either order.  The region may not be empty.
+
+tt(narrow-to-region) may be used as a widget or called as a function from a
+user-defined widget; by default, the text outside the editable area remains
+visible.  Various options and arguments are available when it is called as
+a function.
+
+The options tt(-p) var(pretext) and tt(-P) var(posttext) may be
+used to replace the text before and after the display for the duration of
+the function; either or both may be an empty string.
+
+If the option tt(-n) is also given, var(pretext) or var(posttext) will only
+be inserted if there is text before or after the region respectively which
+will be made invisible.
+
+Two numeric arguments may be given which will be used instead of the cursor
+and mark positions.
+
+tt(narrow-to-region-invisible) is a simple widget which calls
+tt(narrow-to-region) with arguments which replace any text outside the
+region with `tt(...)'.
+
+On return from both widgets, the display is restored by any zle command
+which would usually cause the line to be accepted or aborted.  Hence an
+additional such command is required to accept or abort the current line.
+
+The return status of both widgets is zero if the line was accepted, else
+non-zero.
+)
 tindex(predict-on)
 tindex(predict-off)
 item(tt(predict-on))(
Index: Functions/Zle/narrow-to-region
===================================================================
RCS file: Functions/Zle/narrow-to-region
diff -N Functions/Zle/narrow-to-region
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Functions/Zle/narrow-to-region	4 Jul 2002 13:24:46 -0000
@@ -0,0 +1,82 @@
+# Restrict the start of the editable line to the region between cursor
+# and mark (including the character at the end).  Can be bound used as
+# a zle widget, or called as a function from another widget.
+#
+# Optionally accepts exactly two arguments, which are used instead of
+# $CURSOR and $MARK as limits to the range.
+#
+# Other options:
+#   -p pretext   show `pretext' instead of the buffer text before the region.
+#   -P posttext  show  `posttext' instead of the buffer text after the region.
+#   -n           Only replace the text before or after the region with
+#                the -p or -P options if the text was not empty.
+# Either or both may be empty.
+
+emulate -L zsh
+setopt extendedglob
+
+local lbuffer rbuffer predisplay=$PREDISPLAY postdisplay=$POSTDISPLAY
+integer start end swap cursor=$CURSOR mark=$MARK stat
+
+local opt pretext posttext usepretext useposttext nonempty
+
+while getopts "np:P:" opt; do
+  case $opt in
+    (n) nonempty=1
+	;;
+    (p) pretext=$OPTARG usepretext=1
+	;;
+    (P) posttext=$OPTARG useposttext=1
+	;;
+    (*) [[ $opt != '?' ]] && print "$0: unhandled option: $opt" >&2
+	return 1
+	;;
+  esac
+done
+(( OPTIND > 1 )) && shift $(( OPTIND - 1 ))
+
+if (( $# )); then
+  if (( $# != 2 )); then
+    zle -M "$0: supply zero or two arguments"
+    return 1
+  fi
+  start=$1
+  end=$2
+else
+  start=$MARK
+  end=$CURSOR
+fi
+
+if (( start == end )); then
+  return 1
+elif (( start > end )); then
+  swap=start
+  start=end
+  end=swap
+fi
+
+(( end++, cursor -= start, mark -= start ))
+
+lbuffer=${BUFFER[1,start]}
+if [[ -z $usepretext || ( -n $nonempty && -z $lbuffer ) ]]; then
+  pretext=$lbuffer
+fi
+rbuffer=${BUFFER[end,-1]}
+if [[ -z $useposttext || ( -n $nonempty && -z $rbuffer ) ]]; then
+  posttext=$rbuffer
+fi
+PREDISPLAY="$predisplay$pretext"
+POSTDISPLAY="$posttext$postdisplay"
+BUFFER=${BUFFER[start+1,end-1]}
+CURSOR=$cursor
+MARK=$mark
+
+zle recursive-edit
+stat=$?
+
+PREDISPLAY=$predisplay
+POSTDISPLAY=$postdisplay
+LBUFFER="$lbuffer$LBUFFER"
+RBUFFER="$RBUFFER$rbuffer"
+
+return $stat
Index: Functions/Zle/narrow-to-region-invisible
===================================================================
RCS file: Functions/Zle/narrow-to-region-invisible
diff -N Functions/Zle/narrow-to-region-invisible
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ Functions/Zle/narrow-to-region-invisible	4 Jul 2002 13:24:46 -0000
@@ -0,0 +1,5 @@
+# As narrow-to-region, but replaces the text outside the editable region
+# with `...' if it was non-empty.  Can be used directly as a widget.
+
+autoload -U narrow-to-region
+narrow-to-region -p '...' -P '...' -n

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 392070


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