I updated method. Eccma can looks at it if want. Its more useful now.
91 edits of post.
26 days ago(+1)
Some text relayed from eccma.
Eccma417:https://itch.io/t/4233858/tot-one-suggestion-for-improvement his text flag fix confirmed better. but i m gonna do it with my style 
Eccma417:point is allow it load text flag. not SAVE TEXT
Eccma417:in this case. some new def will be more reasonaable
Eccma417:also. reset her hole record
Eccma417:for trade.... now sure if i can do it... there are alot trade rely by custom codes and logic... make it a json need a stable strature.
Eccma417: ex... i would add more item if a quest done
Eccma417:or even lona is too weak
Eccma417:or fskadfglsdflgkjsdlfgkjaoewirjf
Ok. It's fine.
My own quest is done.
Eccma's quest has started.
—
At the very least, I've already figured out a way for modders to add items to traders without overwriting dialogs.
While Eccma's quest is not yet done all of this will not happen centrally. But it will still work.
Eccma can use json method for simple cases (may be it's possible to add some tags into items in jsons of traders, for story_stats[""] or actor.stat[""] check? ShopNerf is already added by me in code above), and use old method when it's something really unique, and slowly extend the json method. Let's say, Eccma can use a hybrid way, for short. And even that is enough for modders to connect to the existing structure and use it then.