38670: New function for managing ZLE special widgets, modeled after Functions/Misc/add-zsh-hook.

Functions/Zle/add-zle-hook-widget

@@ -0,0 +1,140 @@
+# Add to HOOK the given WIDGET
+# 
+# HOOK is one of isearch-exit, isearch-update, line-pre-redraw, line-init,
+# line-finish, history-line-set, keymap-select (the zle- prefix is not
+# required).
+#
+# WIDGET may be of the form INDEX:NAME in which case the INDEX determines
+# the order in which the widget executes relative to other hook widgets.
+# 
+# With -d, remove the widget from the hook instead; delete the hook
+# variable if it is empty.
+#
+# -D behaves like -d, but pattern characters are active in the
+# widget name, so any matching widget will be deleted from the hook.
+#
+# Without -d, if the WIDGET is not already defined, a function having the
+# same name is marked for autoload; -U is passed down to autoload if that
+# is given, as are -z and -k.  (This is harmless if the function is
+# already defined.)  The WIDGET is then created with zle -N.
+
+emulate -L zsh
+
+# Setup - create the base functions for hook widgets that call the others
+
+zmodload zsh/parameter || {
+    print -u2 "Need parameter module for zle hooks"
+    return 1
+}
+
+local -a hooktypes=( isearch-exit isearch-update
+                     line-pre-redraw line-init line-finish
+                     history-line-set keymap-select )
+# Stash in zstyle to make it global
+zstyle zle-hook types $hooktypes
+
+for hook in $hooktypes
+do
+  function zle-$hook {
+      local -a hook_widgets
+      local hook
+      # Values of these styles look like number:name
+      # and we run them in number order
+      # $funcstack is more reliable than $0
+      # Also, ksh_arrays is annoying
+      emulate zsh -c 'zstyle -a $funcstack[2] widgets hook_widgets'
+      for hook in "${@${(@on)hook_widgets}#*:}"
+      do
+	zle "$hook" -Nw || return
+      done
+      return 0
+  }
+done
+
+# Redefine ourself with the setup left out
+
+function add-zle-hook-widget {
+    local -a hooktypes
+    zstyle -a zle-hook types hooktypes
+
+    # This part copied from add-zsh-hook
+    local usage="Usage: $0 hook widgetname\nValid hooks are:\n  $hooktypes"
+
+    local opt
+    local -a autoopts
+    integer del list help
+
+    while getopts "dDhLUzk" opt; do
+	case $opt in
+	    (d)
+	    del=1
+	    ;;
+
+	    (D)
+	    del=2
+	    ;;
+
+	    (h)
+	    help=1
+	    ;;
+
+	    (L)
+	    list=1
+	    ;;
+
+	    ([Uzk])
+	    autoopts+=(-$opt)
+	    ;;
+
+	    (*)
+	    return 1
+	    ;;
+	esac
+    done
+    shift $(( OPTIND - 1 ))
+
+    if (( list )); then
+	zstyle -L "zle-(${1:-${(@j:|:)hooktypes}})" widgets
+	return $?
+    elif (( help || $# != 2 || ${hooktypes[(I)${1#zle-}]} == 0 )); then
+	print -u$(( 2 - help )) $usage
+	return $(( 1 - help ))
+    fi
+
+    local -aU extant_hooks
+    local hook="zle-${1#zle-}"
+    local fn="$2"
+
+    if (( del )); then
+        # delete, if hook is set
+	if zstyle -g extant_hooks "$hook" widgets; then
+	    if (( del == 2 )); then
+		set -A extant_hooks ${extant_hooks:#(<->:|)${~fn}}
+	    else
+		set -A extant_hooks ${extant_hooks:#(<->:|)$fn}
+	    fi
+            # unset if no remaining entries
+	    if (( ${#extant_hooks} )); then
+		zstyle "$hook" widgets "${extant_hooks[@]}"
+	    else
+		zstyle -d "$hook" widgets
+	    fi
+	fi
+    else
+	zstyle -g extant_hooks "$hook" widgets
+	extant_hooks+=("$fn")
+	zstyle -- "$hook" widgets "${extant_hooks[@]}"
+	if [[ -z "${widgets[$fn]}" ]]; then
+	    autoload "${autoopts[@]}" -- "$fn"
+	    zle -N "$fn"
+	fi
+	if [[ -z "${widgets[$hook]}" ]]; then
+	    zle -N "$hook"
+	fi
+    fi
+}
+
+# Handle zsh autoloading conventions
+if [[ "$zsh_eval_context" = *loadautofunc && ! -o kshautoload ]]; then
+    add-zle-hook-widget "$@"
+fi