How would I adapt dialogue system for conditional variables?

I've noticed there are a lot of branching dialogue systems out there designed to allow you to use CSVs or JSON rather than doing Events for everything. However, in my game concept, a dialogue with any given NPC will branch at multiple points according to various variables (such as whether you've talked to the NPC before, whether you've done the NPC a favor, your character's personal qualities, etc.). I haven't found a dialogue system implementation that allows for this (the ones in the How Do I FAQ don't seem to); how would I go about it? Has one already been made that has that sort of flexibility? Happy to spend money in the Scirra store if that's what is called for.

I once implemented conditionnal branching using XML and a Dictionnary. The XML store the conditions and the actual dialogue, and the Dictionnary hold the game's variables that the conditions can use. I might add that to my dialogue system already in the store... Meanwhile, I guess you could ask me for some tips.

I'm surprised that a dialogue system hasn't been posted on the C2 store sooner! If yours were conditional, it would be near-perfect for my purposes.

As for tips -- how did you format the XML/JSON to reference the dictionary variables?

I can't find that capx for the life of me but if I recall correctly, I used an XML syntax like this:

<events>
    <event id="id1" x="50" y="50">
        <branches>
            <branch>
                <cnds>
                    <cnd>
                         <lop>litteral or #keyInDictionnary</lop>
                         <cp>(something to identify what kind of comparison)</cp>
                         <rop>litteral or #keyInDictionnary</rop>
                         {add more <lop>,<cp> and <rop> nodes for more conditions using a logical OR}
                    </cnd>
                    {add more <cnd> nodes for more conditions using a logical AND}
                </cnds>
                {... multiples nodes for information on sprite animation, direction, path, speed, etc. can be added here}
                <acts>
                    <act type="Dialogue">
                        <dialogueData>{dialogue data in whatever format}</dialogueData>
                    </act>
                    <act type="ChangeVar">
                         <varKey>key litteral</varKey>
                         <varOp>{kind of operation (add, substract, set)}</varOp>
                         <varValue>litteral or #keyInDictionnary</varValue>
                    </act>
                    {add more <act> nodes for more actions on this particular branch, with "type" values to anything you want, which will be interpreted to do whatever you see fit}
                </acts>
            </branch>
            {add more <branch> nodes to allow for multiple possibilities of actions from the same "event", branching should occur only once per event activation, branching at the first branch with satisfied conditions}
        </branches>
    </event>
    {add more <event> nodes to place more events on the map}
</events>[/code:1z5h1uju]

You then need quite a lot of XPath magic and events acrobatics to interpret all of this correctly, but when done correctly you can do pretty much anything you want, à la RPG Maker. You could also limit yourself to dialogue only, but my system was meant to be quite versatile.

Excellent, thanks! I've used XPath at work, so I'm comfortable with that.

Just wondering -- I've heard that JSON is better than XML for dialogue-heavy games. Do you agree? Or are there good reasons for doing this with XML rather than JSON?

JSON is definitely faster, but the data volume is most likely not heavy enough for it to make a difference. I find it easier to navigate with XPath than using JSON... maybe with a decent JSON plugin I would consider it over XML.

JSON is definitely faster, but the data volume is most likely not heavy enough for it to make a difference. I find it easier to navigate with XPath than using JSON... maybe with a decent JSON plugin I would consider it over XML.

The goal is many thousands of lines of dialogue by the end, so speed might come into play eventually? Hmm.

In a single file ? Then I guess you should stick with JSON ! But I don't know what kind of data plugin would be best to load it in... I think this could work.