Dynamic

Handle reflection-based dispatch for members of structural types.

Given x.a, where x is of (widened) type T (a value type or a nullary method type), and x.a is of type U, map x.a to the equivalent of:

x1.selectDynamic("a").asInstanceOf[U]

where x1 is x adapted to Selectable.

Given x.a(a11, ..., a1n)...(aN1, ..., aNn), where x.a is of (widened) type (T11, ..., T1n)...(TN1, ..., TNn): R, it is desugared to:

x1.applyDynamic("a")(a11, ..., a1n, ..., aN1, ..., aNn)
  .asInstanceOf[R]

If this call resolves to an applyDynamic method that takes a Class[?]* as second parameter, we further rewrite this call to scala

x1.applyDynamic("a", c11, ..., c1n, ..., cN1, ... cNn)
                (a11, ..., a1n, ..., aN1, ..., aNn)
  .asInstanceOf[R]

where c11, ..., cNn are the classOf constants representing the erasures of T11, ..., TNn.

It's an error if U is neither a value nor a method type, or a dependent method type

Translate selection that does not typecheck according to the normal rules into a applyDynamic/applyDynamicNamed. foo.bar(baz0, baz1, ...) ~~> foo.applyDynamic(bar)(baz0, baz1, ...) foo.bar[T0, ...](baz0, baz1, ...) ~~> foo.applyDynamicT0, ...(baz0, baz1, ...) foo.bar(x = bazX, y = bazY, baz, ...) ~~> foo.applyDynamicNamed("bar")(("x", bazX), ("y", bazY), ("", baz), ...) foo.bar[T0, ...](x = bazX, y = bazY, baz, ...) ~~> foo.applyDynamicNamedT0, ...(("x", bazX), ("y", bazY), ("", baz), ...)

Translate selection that does not typecheck according to the normal rules into a updateDynamic. foo.bar = baz ~~> foo.updateDynamic(bar)(baz)

Translate selection that does not typecheck according to the normal rules into a selectDynamic. foo.bar ~~> foo.selectDynamic(bar) foo.bar[T0, ...] ~~> foo.selectDynamicT0, ...

Note: inner part of translation foo.bar(baz) = quux ~~> foo.selectDynamic(bar).update(baz, quux) is achieved through an existing transformation of in typedAssign [foo.bar(baz) = quux ~~> foo.bar.update(baz, quux)].