Supporting Dave A, type-based calls are much more likely to be used than
instance calls, unlike with dynamicType/type(of:)
Term stdlib search gist search Google site:github +swift
sizeof 157 169 4880
sizeofValue 4 34 584
alignof 44 11 334
alignofValue 5 5 154
strideof 347 19 347
strideofValue 4 5 163
Type-based calls like sizeof() are poor candidates for parameter labels. While
it's acceptable to write sizeof(Int), but one must write size(of: Int.self)
(with the trailing self) when the function has a label. For this reason, this
proposal prefers using no-label calls for types (otherwise they would have been
ofType) and labeled calls for values:
print(sizeof(Int)) // works
print(sizeof(Int.self)) // works
func withoutLabel<T>(thetype: T.Type) -> Int { return sizeof(T) }
func withLabel<T>(label label: T.Type) -> Int { return sizeof(T) }
// Works
print(withoutLabel(Int))
// Works
print(withLabel(label: Int.self))
// Does not work
// error: cannot create a single-element tuple with an element label
// print(withLabel(label: Int))
So with this in mind:
/// Returns the contiguous memory footprint of `T`.
///
/// Does not include any dynamically-allocated or "remote" storage.
/// In particular, `size(X.self)`, when `X` is a class type, is the
/// same regardless of how many stored properties `X` has.
public func size<T>(_: T.Type) -> Int
/// Returns the contiguous memory footprint of `T`.
///
/// Does not include any dynamically-allocated or "remote" storage.
/// In particular, `size(of: a)`, when `a` is a class instance, is the
/// same regardless of how many stored properties `a` has.
public func size<T>(of: T) -> Int
/// Returns the least possible interval between distinct instances of
/// `T` in memory. The result is always positive.
public func spacing<T>(_: T.Type) -> Int
/// Returns the least possible interval between distinct instances of
/// `T` in memory. The result is always positive.
public func spacing<T>(of: T) -> Int
/// Returns the minimum memory alignment of `T`.
public func alignment<T>(_: T.Type) -> Int
/// Returns the minimum memory alignment of `T`.
public func alignment<T>(of: T) -> Int
-- E_______________________________________________
swift-evolution mailing list
[email protected]
https://lists.swift.org/mailman/listinfo/swift-evolution
