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Many state isolation๏
๐ข Beginner ยท Lesson 29
"many" means ISOLATED - each melded instance owns its own state; mutating one never leaks into the next. The confusion this example prevents: expecting fresh objects to share anything.
Before you run๏
Use the Beginner guide for prerequisite concepts. Run from a checkout with Melder installed and Python 3.14 free-threading selected. The collection download includes the level's local helper modules.
Run the saved script๏
python UX_and_AIX_experiences/01_beginner/29_many_state_isolation.py
py -3.14t UX_and_AIX_experiences/01_beginner/29_many_state_isolation.py
Public surface๏
md.Existence "many" state isolation
Code๏
1"""
2TIER: beginner (29)
3GOAL: "many" means ISOLATED - each melded instance owns its own state;
4 mutating one never leaks into the next. The confusion this
5 example prevents: expecting fresh objects to share anything.
6SURFACE EXERCISED: md.Existence "many" state isolation
7"""
8import melder as md
9
10
11class Basket:
12 def __init__(self) -> None:
13 self.items: list[str] = []
14
15
16def main() -> None:
17 book = md.Spellbook()
18 book.bind(spell=Basket, existence="many")
19 conduit = book.conjure()
20
21 first = conduit.meld(spell=Basket)
22 first.items.append("apples")
23 second = conduit.meld(spell=Basket)
24 assert first.items == ["apples"] and second.items == []
25 print("fresh instances, fresh state:", first.items, "vs", second.items)
26
27
28if __name__ == "__main__":
29 main()
Check the outcome๏
The script contains its own assertions or demonstrated refusal paths. Run it to evaluate those checks against your installed version. The code above is taken directly from the saved file; no run output is invented here.