Swift 6.4 migration and exhancements (#1)
This PR contains the work done to update the library and the attached example project to use the Swift 6.4 computer as a minimum supported version and also, to use the latest features introduced in it. Reviewed-on: #1 Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
This commit was merged in pull request #1.
This commit is contained in:
@@ -1,21 +1,16 @@
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// A public import: `addFunction(_:name:)` and `pushFunction(_:)` expose the
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// `CFunction` alias of `lua_CFunction` in their public signatures.
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// Internal suffices: `CFunction.swift` publicly imports `lua_CFunction`.
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internal import CPlaydate
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/// The cached `playdate->lua` C API table.
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var luaAPI: UnsafePointer<playdate_lua> { Playdate.luaAPI.unsafelyUnwrapped }
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/// The Lua bridge: registering C functions and classes, and exchanging
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/// values with Lua code.
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///
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/// Lua callbacks are C function pointers without userdata, so functions
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/// registered here must be `@convention(c)` (the `CFunction` typealias),
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/// not capturing closures.
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/// Lua bridge: registers C functions and classes; exchanges values via the Lua stack.
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/// Registered functions must be `CFunction`s (`@convention(c)`), not capturing
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/// closures. Argument positions are 1-based.
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public enum Lua {}
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extension Lua {
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/// Buffers passed to `registerClass`/`addFunction`; the OS may keep
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/// referencing them, so they are retained for the life of the game.
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/// Strings and tables passed to `registerClass`; never freed (the OS may keep them).
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nonisolated(unsafe) private static var retainedBuffers: [UnsafeMutableRawPointer] = []
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private static func retainedCString(_ string: String) -> UnsafePointer<CChar> {
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@@ -26,25 +21,23 @@ extension Lua {
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// MARK: - Registration
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/// Makes `function` callable from Lua as `name` (which may contain dots
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/// for namespacing, e.g. "mylib.myfunc").
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/// Makes `function` callable from Lua as `name`, which may be a dotted path
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/// ("mylib.myfunc"). Throws `PlaydateError`.
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public static func addFunction(_ function: CFunction, name: String) throws(PlaydateError) {
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var error: UnsafePointer<CChar>?
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let ok = name.withPlaydateCString {
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let ok = name.withCString {
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luaAPI.pointee.addFunction.unsafelyUnwrapped(function, $0, &error) != 0
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}
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if !ok { throw PlaydateError(cString: error) }
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}
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/// Registers a Lua class named `name` with the given methods and
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/// constants. When `isStatic` is `true` a plain table of functions is
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/// created instead of a class.
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/// Registers class `name` (a metatable; a plain table if `isStatic`) with
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/// `functions` and constant `values`. Throws `PlaydateError`.
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public static func registerClass(name: String,
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functions: [(name: String, function: CFunction)],
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values: [ClassValue] = [],
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isStatic: Bool = false) throws(PlaydateError) {
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// The registration tables are kept alive permanently: the OS
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// documents no copying guarantees for them.
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// Leaked on purpose: the C API is not documented to copy them.
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var registrations: [lua_reg] = functions.map { entry in
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lua_reg(name: retainedCString(entry.name), func: entry.function)
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}
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@@ -72,7 +65,7 @@ extension Lua {
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retainedBuffers.append(UnsafeMutableRawPointer(constantsBuffer))
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var error: UnsafePointer<CChar>?
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let ok = name.withPlaydateCString {
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let ok = name.withCString {
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luaAPI.pointee.registerClass.unsafelyUnwrapped($0, registrationsBuffer,
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values.isEmpty ? nil : constantsBuffer,
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isStatic ? 1 : 0, &error) != 0
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@@ -80,36 +73,34 @@ extension Lua {
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if !ok { throw PlaydateError(cString: error) }
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}
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/// Pushes a function onto the stack, e.g. for `setUserValue`.
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public static func pushFunction(_ function: CFunction) {
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luaAPI.pointee.pushFunction.unsafelyUnwrapped(function)
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}
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/// From a class's `__index` callback: looks up the key in the instance
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/// metatable first. Returns 1 if a value was found.
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/// Looks up the indexed key in the class metatable; call first in `__index`.
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/// If `true`, the value is on the stack and `__index` should return 1.
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public static func indexMetatable() -> Bool {
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luaAPI.pointee.indexMetatable.unsafelyUnwrapped() != 0
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}
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/// Pauses the Lua runtime.
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/// Stops the Lua run loop.
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public static func stop() {
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luaAPI.pointee.stop.unsafelyUnwrapped()
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}
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/// Resumes the Lua runtime.
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/// Restarts the Lua run loop after `stop()`.
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public static func start() {
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luaAPI.pointee.start.unsafelyUnwrapped()
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}
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// MARK: - Arguments
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/// The number of arguments the Lua caller passed. Positions are 1-based.
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/// The number of arguments to the current Lua call.
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public static var argumentCount: Int {
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Int(luaAPI.pointee.getArgCount.unsafelyUnwrapped())
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}
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/// The type of the argument at 1-based `position`; for objects, also the
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/// class name.
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/// The argument's type, plus its metatable name if `.object` (else `nil`).
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public static func argumentType(at position: Int) -> (kind: Kind, className: String?) {
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var className: UnsafePointer<CChar>?
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let type = luaAPI.pointee.getArgType.unsafelyUnwrapped(Int32(position), &className)
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@@ -132,11 +123,12 @@ extension Lua {
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luaAPI.pointee.getArgFloat.unsafelyUnwrapped(Int32(position))
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}
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/// `nil` if the C API returns `NULL`.
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public static func stringArgument(at position: Int) -> String? {
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String(playdateCString: luaAPI.pointee.getArgString.unsafelyUnwrapped(Int32(position)))
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}
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/// The argument as raw bytes (which may contain embedded zeros).
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/// Raw bytes (may contain zeros), or `nil` if the C API returns `NULL`.
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public static func bytesArgument(at position: Int) -> [UInt8]? {
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var length = 0
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guard let bytes = luaAPI.pointee.getArgBytes.unsafelyUnwrapped(Int32(position), &length) else {
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@@ -146,28 +138,24 @@ extension Lua {
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return [UInt8](buffer)
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}
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/// The argument as an object instance of class `type`, with the
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/// `UDObject` handle for retaining it.
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/// Instance of class `type` and its handle; `object` is `nil` on type mismatch.
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public static func objectArgument(at position: Int, type: String)
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-> (object: UnsafeMutableRawPointer?, userdataObject: UDObject?) {
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var userdataObject: OpaquePointer?
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// The C API takes a non-const class name but only reads it, so the
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// stack copy can be passed with a mutating cast.
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let object = type.withPlaydateCString { cType in
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// The C API declares the class name non-const but only reads it.
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let object = type.withCString { cType in
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luaAPI.pointee.getArgObject.unsafelyUnwrapped(
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Int32(position), UnsafeMutablePointer(mutating: cType), &userdataObject)
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}
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return (object, userdataObject.map { UDObject(pointer: $0) })
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}
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/// The argument as a bitmap. References an object owned by Lua; retain
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/// the Lua value while using it.
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/// Lua owns the bitmap; keep the Lua value alive while using it.
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public static func bitmapArgument(at position: Int) -> Graphics.Bitmap? {
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guard let bitmap = luaAPI.pointee.getBitmap.unsafelyUnwrapped(Int32(position)) else { return nil }
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return Graphics.Bitmap(pointer: bitmap, isOwned: false)
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}
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/// The argument as a sprite.
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public static func spriteArgument(at position: Int) -> Sprite? {
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guard let sprite = luaAPI.pointee.getSprite.unsafelyUnwrapped(Int32(position)) else { return nil }
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return Sprite.wrapper(for: sprite)
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@@ -175,33 +163,27 @@ extension Lua {
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// MARK: - Return values
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/// Pushes nil onto the stack.
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public static func pushNil() {
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luaAPI.pointee.pushNil.unsafelyUnwrapped()
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}
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/// Pushes a boolean onto the stack.
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public static func push(_ value: Bool) {
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luaAPI.pointee.pushBool.unsafelyUnwrapped(value ? 1 : 0)
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}
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/// Pushes an integer onto the stack.
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public static func push(_ value: Int) {
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luaAPI.pointee.pushInt.unsafelyUnwrapped(Int32(value))
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}
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/// Pushes a float onto the stack.
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public static func push(_ value: Float) {
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luaAPI.pointee.pushFloat.unsafelyUnwrapped(value)
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}
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/// Pushes a string onto the stack.
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public static func push(_ value: String) {
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value.withPlaydateCString { luaAPI.pointee.pushString.unsafelyUnwrapped($0) }
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value.withCString { luaAPI.pointee.pushString.unsafelyUnwrapped($0) }
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}
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/// Pushes raw bytes (which may contain embedded zeros) onto the stack
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/// as a Lua string.
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/// Pushes `bytes` as a Lua string; zeros are kept.
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public static func push(bytes: [UInt8]) {
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bytes.withUnsafeBytes { buffer in
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luaAPI.pointee.pushBytes.unsafelyUnwrapped(
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@@ -209,24 +191,21 @@ extension Lua {
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}
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}
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/// Pushes a bitmap onto the stack.
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public static func push(_ bitmap: Graphics.Bitmap) {
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luaAPI.pointee.pushBitmap.unsafelyUnwrapped(bitmap.pointer)
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}
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/// Pushes a sprite onto the stack.
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public static func push(_ sprite: Sprite) {
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luaAPI.pointee.pushSprite.unsafelyUnwrapped(sprite.pointer)
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}
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/// Wraps `object` in a Lua instance of class `type` and pushes it, with
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/// `valueCount` extra user-value slots.
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/// Pushes `object` as an instance of class `type` with `valueCount` user-value
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/// slots. Returns its handle, or `nil` on failure.
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@discardableResult
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public static func pushObject(_ object: UnsafeMutableRawPointer, type: String,
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valueCount: Int = 0) -> UDObject? {
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// The C API takes a non-const class name but only reads it, so the
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// stack copy can be passed with a mutating cast.
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let pointer = type.withPlaydateCString { cType in
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// The C API declares the class name non-const but only reads it.
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let pointer = type.withCString { cType in
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luaAPI.pointee.pushObject.unsafelyUnwrapped(
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object, UnsafeMutablePointer(mutating: cType), Int32(valueCount))
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}
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@@ -236,11 +215,11 @@ extension Lua {
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// MARK: - Calling Lua
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/// Calls the Lua function `name`. Push the arguments onto the stack
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/// first. Calling Lua from Swift has overhead; use sparingly.
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/// Calls Lua function `name` (dotted path allowed) with the `argumentCount`
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/// arguments already pushed. Slow; use sparingly. Throws `PlaydateError`.
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public static func callFunction(_ name: String, argumentCount: Int = 0) throws(PlaydateError) {
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var error: UnsafePointer<CChar>?
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let ok = name.withPlaydateCString {
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let ok = name.withCString {
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luaAPI.pointee.callFunction.unsafelyUnwrapped($0, Int32(argumentCount), &error) != 0
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}
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if !ok { throw PlaydateError(cString: error) }
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