This nightly adds a new "Add/Modify Container" FRED dialog, which you can reach from the right-click menu in FRED's Events Editor.
SEXP containers support storing/retrieving data in much more sophisticated ways than what variables can do. They'll allow for making missions that would otherwise be infeasible.
Containers come in two types:
list (aka "linked list") and
map (aka "unordered map"/"hash map"/"dictionary").
Right now, all you can do is save/load containers in FRED. Any nightly after June 1 can load containers, but the game can't (yet!) do anything with them.
Many more features, including a bunch of new SEXPs, will be rolled out over the coming months. Stay tuned.
Karajorma and I will work on documenting containers and writing tutorials.
If you're open to trying out the new dialog, we'd love to get your feedback.
For support, bug reports, or feature requests, you can post in the
containers thread and/or post on the #scp channel on HLP Discord and @ tag both me and Karajorma.
Special thanks to Goober5000 for his thorough PR reviews. The code is much better for them.
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