EasyDialog

Free to use in any context for any reason. Provided by Pazako Karu
Take on high-security dialogs the easy way!
Simplifies listens and contextual information greatly into gets and sets. Each dialog uses a new listen, a new channel, and listens only to the originator of the dialog. Any use of a dialog will trigger self-clean garbage collection of old listens and values.
Caveats: If the last person to dialog chose to Ignore or close without a getDialog response, 1 listen event will remain in queue and active until another person touches it. This is not generally a problem, and this will be rare. If this trivial amount of lag is a problem (its a very specific listen, least possible lag), run cleanDialogs() on a timer after click events or after special events like reset.
Example use case below.
list DIALOG_DATA;
setDialog(key id, string caption, list buttons, integer context) // Creates a listen and a dialog
{ getDialog(id); // Clean up beforehand
 if (llList2Integer(DIALOG_DATA, -3) > llGetTime()) // Clear old
 { integer i;
 for (i = 0; i < llGetListLength(DIALOG_DATA); i++)
 llListenRemove((integer)DIALOG_DATA[i+2]);
 DIALOG_DATA = []; // If the last timed out, all are invalid
 }
 integer channel = -(integer)llFrand(DEBUG_CHANNEL);
 DIALOG_DATA += [llGetTime()+60, id, llListen(channel, llKey2Name(id), id, ""), context]; // Time, ID, Listen Handle, context
 llDialog(id, caption, buttons, channel);
}
integer getDialog(key id)
{ integer index = llListFindList(DIALOG_DATA, [id]); // Finds the dialog, if it exists
 integer context = (integer)DIALOG_DATA[index+2]; // Context that the dialog was sent in, integer
 if (~index) // If it does...
 { llListenRemove(llList2Integer(DIALOG_DATA, index+1)); // Remove the listen
 DIALOG_DATA = llDeleteSubList(DIALOG_DATA, index-1, index+1); // Free the memory
 }
 else context = -1; // If it doesn't exist, return nothing
 return context; // Return the context
}
cleanDialogs()
{ // Removes our listens and clears data
 integer index; // Time, Id, Listen, Context
 for (index = 2; index < llGetListLength(DIALOG_DATA); index+=4)
 llListenRemove((integer)DIALOG_DATA[index]);
 DIALOG_DATA=[];
}
= Example use =
Context is useful for creating sub-menus without complicating the listen logic. As you can have a precheck of context, you can keep simple "Yes" and "No" answers, rather than the often-used trope of including special characters with each menu option. No additional variables or flags are necessary. 
Think of 'context' the same as a 'listen handle', except it is set when you call a dialog, so you know the source and context of what your listen is handling. 
integer context_pancake = 1;
integer context_pie = 2;
default
{
 state_entry()
 {
 setDialog(llGetOwner(), "Do you like pancakes?", ["Yes", "No"], context_pancake);
 }
 listen(integer channel, key id, string message)
 {
 integer context = getDialog(id); // This gets our context number back, and cleans up the listen event
 if (context == context_pancake) // Do they like pancakes?
 { // Notice here we know the dialog is about pancakes, so we can use Yes/No exactly
 if (message == "Yes")
 llRegionSayTo(llGetOwner(), 0, "Glad to hear it!");
 else if (message == "No")
 setDialog(llGetOwner(), "Sorry, how about pie?", ["Yes", "No"], context_pie);
 }
 else if (context == context_pie) // They didn't like pancakes, how about pie? (sub-menu from "No" earlier)
 { // And here we know the dialog is about pie.
 if (message == "Yes")
 llRegionSayTo(llGetOwner(), 0, "Pie is my second favorite!");
 else if (message == "No")
 llRegionSayTo(llGetOwner(), 0, "I guess we dont have much in common :(");
 }
 }
}