@prog randomline.muf
1 9999 d
1 i
(
 randomline.muf - pick a random line from a list.
 Usage: link an exit to this program.  By default, the list is stored in
 _list1:, _list2:, etc, properties on the dbref the exit is attached to.
 You can change the property prefix with a property _prefix: on the exit
 [its value must be the prefix string]; you can change the dbref with a
 property _holder: on the exit [its value must be the dbref number,
 without the #].

 This program caches the count of the list in a property _list#: [or
 whatever prefix was specified] on the dbref.  It updates this property
 automatically.

 If the list contains no lines, nothing is printed.

 Unless the exit is owned by a royal or wiz, the holder dbref must be owned
 by the same player as the exit.

 The triggering exit is located with trig; messages are sent to "me" match.
)
$def holder-prop "_holder"
$def prefix-prop "_prefix"
$def default-prefix "_list"
: say "me" match swap notify ;
: prefix-str (trigger -- str)
	dup prefix-prop prop-exists? if
		prefix-prop getpropstr
	else
		pop default-prefix
	then
;
: recompute-list-count (holder pfx -- holder pfx count)
	1 begin
		( holder pfx n )
		over over intostr strcat 4 pick swap prop-exists?
	while
		1 +
	loop
	1 -
	dup 1 < if pop over over "#" strcat remove_prop 0 exit then
	3 pick 3 pick "#" strcat 3 pick intostr addprop
;
: get-list-count (holder pfx -- holder pfx count)
	over over "#" strcat getpropstr atoi
	( holder pfx n )
	dup if
		over over 1 + intostr strcat 4 pick swap prop-exists?
		not if exit then
	then
	pop recompute-list-count
;
: main
	pop
	trig holder-prop prop-exists? if
		trig holder-prop getpropstr atoi dbref
	else
		trig location
	then
	dup ok? if
		dup owner trig owner dbcmp if
			0
		else
			trig owner true-royalty? not
		then
	else
		1
	then
	if pop "Permission denied." say exit then
	( holder )
	trig prefix-str
	( holder pfx )
	get-list-count
	( holder pfx count )
	dup 1 < if pop pop pop exit then
	random swap % 1 + intostr strcat
	over over prop-exists? not if
		pop trig prefix-str recompute-list-count
		random swap % 1 + intostr strcat
	then
	getpropstr say
;
.
c
q