coerceCallableToFunction static method

Object? coerceCallableToFunction(InterpreterVisitor visitor, Object? value)

GEN-110: Wrap a Callable (typically an InterpretedFunction) as a native Dart function value, so it can be passed to native code that expects a typed Function argument — e.g. VoidCallback, ValueChanged<T>, StateSetter, (BuildContext) => Widget.

Used by visitMethodInvocation / visitFunctionExpressionInvocation at the Function.apply(...) fallback. Without this wrapping the underlying Dart runtime throws type 'InterpretedFunction' is not a subtype of type '() => void' because the interpreter's Callable.call signature ((visitor, positional, [named, typeArgs])) doesn't match any native function type. The arity of the wrapper matches the Callable's declared required-positional count.

Mirrors tom_d4rt/lib/src/generator/d4.dart per the quest's sync rule.

Implementation

static Object? coerceCallableToFunction(
    InterpreterVisitor visitor, Object? value) {
  if (value is! Callable) return value;
  final n = value.arity;
  switch (n) {
    case 0:
      return () => callInterpreterCallback(visitor, value, const []);
    case 1:
      return (a) => callInterpreterCallback(visitor, value, [a]);
    case 2:
      return (a, b) => callInterpreterCallback(visitor, value, [a, b]);
    case 3:
      return (a, b, c) =>
          callInterpreterCallback(visitor, value, [a, b, c]);
    case 4:
      return (a, b, c, d) =>
          callInterpreterCallback(visitor, value, [a, b, c, d]);
    default:
      return ([p0, p1, p2, p3, p4, p5, p6, p7, p8, p9]) {
        final args = <Object?>[];
        for (final p in [p0, p1, p2, p3, p4, p5, p6, p7, p8, p9]) {
          if (p == null) break;
          args.add(p);
        }
        return callInterpreterCallback(visitor, value, args);
      };
  }
}