Phase 12.7: Nyash文法革命とANCP 90%圧縮技法の発見 - 文法改革完了とFunctionBox実装

docs/development/current/function_values_and_captures.md

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+# Function Values, Captures, and Events
+
+Summary of current behavior and guidelines.
+
+- Function values: created via `function(...) { ... }` produce a `FunctionBox` with
+  captured environment (by-ref for locals via `RefCellBox`, by-value for globals/statics) and optional weak `me`.
+- Assignment cell reflection: assigning to a variable or field bound to `RefCellBox` updates the inner value instead of replacing the cell.
+- `this → me`: inside methods, `this` is bound as `me` for field/method access. External code should prefer `me`.
+- Parent:: syntax: parser groundwork exists for `Parent::method` references; calling from child uses from-call lowering.
+- `?` (propagate): `expr ?` lowers to `isOk`/`getValue` branching and returns early with the Result on error.
+- `peek`: tokenized and parsed; desugars to if-else chain in VM.
+
+Event APIs
+
+- P2PBox.on/onOnce/off: handlers now accept both `MethodBox` and `FunctionBox`.
+  - `MethodBox` handlers invoke the bound method on receive with arguments `(intent, from)`.
+  - `FunctionBox` handlers execute the function body with params bound from `(intent, from)` (excess args ignored).
+
+Notes
+
+- RefCell-backed locals captured by closures will reflect assignments (`x = ...`) in the outer scope.
+- For plugin-backed boxes, assignment and argument passing uses share semantics to preserve identity.
+