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Named bindings๏ƒ

๐ŸŸข Beginner ยท Lesson 04

Two implementations of one shape, told apart by binding_name - the beginner door into disambiguation (spellframes come later).

Before you run๏ƒ

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๏ƒ

python UX_and_AIX_experiences/01_beginner/04_named_bindings.py

py -3.14t UX_and_AIX_experiences/01_beginner/04_named_bindings.py

Download this collection ยท Source on GitHub

Public surface๏ƒ

md.Spellbook, md.Existence, binding_name= on bind/meld

Code๏ƒ

 1"""
 2TIER: beginner (04)
 3GOAL: Two implementations of one shape, told apart by binding_name -
 4      the beginner door into disambiguation (spellframes come later).
 5SURFACE EXERCISED: md.Spellbook, md.Existence, binding_name= on bind/meld
 6"""
 7import melder as md
 8
 9
10class PostgresStore:
11    kind = "postgres"
12
13
14class SqliteStore:
15    kind = "sqlite"
16
17
18def main() -> None:
19    book = md.Spellbook()
20    book.bind(
21        spell=PostgresStore,
22        existence="unique",
23        binding_name="primary",
24    )
25    book.bind(
26        spell=SqliteStore,
27        existence="unique",
28        binding_name="local",
29    )
30    conduit = book.conjure()
31
32    primary = conduit.meld("PostgresStore", binding_name="primary")
33    local = conduit.meld("SqliteStore", binding_name="local")
34    assert primary.kind == "postgres" and local.kind == "sqlite"
35    print("named bindings resolved:", primary.kind, "+", local.kind)
36
37
38if __name__ == "__main__":
39    main()

Check the outcome๏ƒ

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.

More beginner examples ยท Level guide

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