From 749fd503dde69042fcb472e9b3a0e5252e4e9551 Mon Sep 17 00:00:00 2001 From: Greg Date: Wed, 29 May 2019 00:03:51 -0400 Subject: [PATCH] Add README.md and LICENSE. --- LICENSE | 22 ++ README.md | 713 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 735 insertions(+) create mode 100644 LICENSE create mode 100644 README.md diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..6b6f51d --- /dev/null +++ b/LICENSE @@ -0,0 +1,22 @@ +MIT License + +Copyright (c) 2019 Greg Pomerantz +Copyright (c) 2017 Elliot Chance and Izyumov Konstantin + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 index 0000000..6f00ca4 --- /dev/null +++ b/README.md @@ -0,0 +1,713 @@ +# NSWrap + +Create Go language bindings for Objective-C. + +Using NSWrap, you can easily work with many MacOS interfaces, subclasses, +library functions, protocols and delegates entirely in Go. + +# Getting Started + +## Installation + +NSWrap runs on MacOS and requires `clang` (from the XCode command line +tools) and the MacOS system header files. + +```sh +go get gitlab.wow.st/gmp/nswrap +``` + +From your `go` source directory, type: + +```sh +cd gitlab.wow.st/gmp/nswrap/cmd/nswrap +go install +``` + +Since NSWrap uses `clang` to generate an AST from Objective-C input files, you +will need to install XCode and its associated command line tools. Enter +`clang --version` from your terminal prompt to see if you have it installed +already. You will also need to have the Objective-C header files for the +various frameworks you want to use. Look for them in +`/System/Library/Frameworks/*/Headers`. + +## Try Out An Example + +NSWrap is designed to be easy to use. To get started with an example, visit +your Go source directory in a terminal and enter: + +```sh +cd gitlab.wow.st/gmp/nswrap/examples/app +go generate +go build +./app +``` + +# Basic Usage + +## YAML configuration file + +NSWrap takes no command line arguments. All configuration directives are +included in a file named `nswrap.yaml`, which must be found in the directory +from which NSWrap is invoked. + +```yaml +# nswrap.yaml example + +package: MyWrapper +inputfiles: + - /System/Library/Frameworks/Foundation.framework/Headers/Foundation.h + +classes: + - NSString + - NSArray + +frameworks: [ Foundation ] +pragma [ clang diagnostic ignored "-Wformat-security" ] +``` + +Regular expressions are permitted in the names of classes, functions, +protocols and protocol methods, overridden superclass methods, and enums. + +When invoked, NSWrap creates a subdirectory with the name of the package +as specified in `nswrap.yaml` or, by default, `ns` if a package name is not +specified. +In the output directory, a `main.go` file and, if required, `exports.go`, +will be created or overwritten. + +To automatically invoke NSWrap, put a `//go:generate nswrap` comment at the +top of your go source file and use `go generate` to create your Objective-C +bindings. + +NSWrap will look for Objective-C header files where directed under +`inputfiles` in your configuration file. CGo will also automatically +compile and link any Objective-C implementation (`.m`) files found in +this output directory, so put them in there if you are going to be +hand-crafting any Objective-C implementations that need to go in the same +package as your automatically generated bindings. + +## Class and Instance Methods + +NSWrap will create bindings for all classes identified in the `classes` +directive of the configuration file. All of the class and instance methods +are bound to Go and all types identified in the process are wrapped +in Go types (as described below), except for methods that contain prohibited +return types or paramater types (such as blocks and function pointers). + +```go +s1 := ns.NSStringAlloc() // allocate and autorelease an instance of NSString +s2 := ns.NSStringWithSting(s1) // call a class method of NSString +class := ns.NSStringClass() // class method returning the class of NSString +fmt.Println(s2.UTF8String()) // call UTF8String, an NSString instance method +``` + +As seen above, generated class methods will have the same name as their +Objective-C method name, converted to the Go TitleCase convention, prefixed +with the class name, and, if necessary, disambiguated for overloaded +Objective-C methods. Any redundant initial +characters are elided (e.g. the Objective-C +`[NSString stringWithString:aString]` is shortened in Go to +`ns.NSStringWithString(aString)`). Instance methods are carried over +as-is but in TitleCase, and disambiguated for method overloading as described +below. + +Note that while return types and parameter types needed for the binding will +be defined and wrapped for you in Go types, +you will not get any of their methods +unless those types also appear in your NSWrap configuration file. +For example, the `NSDictionaryWithObjects(...)` constructor takes two `NSArray` +parameters, so if you want to use it you will probably want +to have `NSArray` in your configuration file in addition to `NSDictionary`. + +## Overloaded Methods + +Because Go does not allow overloaded function definitions, NSWrap automatically +disambiguates overloaded method names as required. +This is done by successively adding parameter names onto the end of the Go +function name until a unique name is created. + +For example, `NSString` provides the folowing `compare` methods: + +```objective-c +- compare: +- compare:options: +- compare:options:range: +- compare:options:range:locale: +``` + +These are translated into Go as: + +```go +func (o NSString) Compare(string NSString) NSComparisonResult { } + +func (o NSString) CompareOptions(string NSString, mask NSStringCompareOptions) NSComparisonResult { } + +func (o NSString) CompareOptionsRange(string NSString, mask NSStringCompareOptions, + rangeOfReceiverToCompare NSRange) NSComparisonResult { } + +func (o NSString) CompareOptionsRangeLocale(string NSString, mask NSStringCompareOptions, + rangeOfReceiverToCompare NSRange, locale NSObject) NSComparisonResult { } +``` + +## NSString Helpers + +When NSWrap sees a class or instance method ending in `...WithString` (taking +an Objective-C `NSString` as a parameter), it will automatically create an +additional helper method ending in `WithGoString` that takes a Go string. + +```go +str := ns.NSStringWithGoString("** your string goes here **") +fmt.Printf("%s\n",str) +``` + +NSWrap creates a `Char` Go type that is equivalent to a C `char`. A pointer to +`Char` in Go code can therefore be used with Objective-C functions and methods +that take a `char*` parameter. +NSWrap provides the helper functions `CharWithGoString` and `CharWithBytes` +that take, respectively, Go strings and Go byte arrays (`[]byte`) and return +`*Char` in Go. As demonstrated above, NSWrap also provides a `String()` +methods so that the `*Char` and `NSString` types implement the `Stringer` +Go interface. + +## Working With NSObject and its Descendants + +Objective-C Objects are represented in Go by a type and an interface as +follows: + +```go +type Id struct { + ptr unsafe.Pointer +} +func (o Id) Ptr() unsafe.Pointer { return o.ptr } + +type NSObject interface { + Ptr() unsafe.Pointer +} +``` +Other object types in Go are structs that directly or indirectly embed `Id` +and therefore implement `NSObject`. + +* The NSObject Interface + +The `Id` type in Go represents the Objective-C type `id`, which is a pointer +to an Objective-C object. Because `cgo` does not understand this type, +NSWrap will always translate it to a `void*` on the C side. +The `NSObject` interface in Go allows any `NS` type to be used with +generic Objective-C functions. For example: + +```go +o1 := ns.NSStringWithGoString("my string") +s1 := ns.NSSetWithOBjects(o1) +a := ns.NSMutableArrayWithObjects(o1,s1) +``` +Since `NSString` and `NSSet` in Go both implement the `NSObject` interface, +they can both be used as parameters to the `NSMutableArray` constructor. + +This will help you, too, with delegates +(see below). Classes that accept delegates will generally accept any +`NSObject` in ther `initWithDelegate()` or `setDelegate()` methods, and +may or may not test at runtime if the provided object actually +implements the required delegate protocol. + +* Inheritance + +Objective-C permits single inheritance. In Go, this is modeled using +embedding. Top level objects that inherit from `NSObject` in Objective-C +embed the Go type `Id` and therefore implement the `NSObject` Go interface. +Other objects embed their superclass. For example: + +```go +type NSArray struct { Id } +func (o NSArray) Ptr() unsafe.Pointer { return o.ptr } +func (o Id) NSArray() NSArray { + ret := NSArray{} + ret.ptr = o.ptr + return ret +} + +type NSMutableArray struct { NSArray } +func (o NSMutableArray) Ptr() unsafe.Pointer { return o.ptr } +func (o Id) NSMutableArray() NSMutableArray {...} +``` + +Observe: +```go +b := ns.NSButtonAlloc() // NSButton > NSControl > NSView > NSResponder > NSObject +b.InitWithFrame(ns.NSMakeRect(100,100,200,200)) // Method of NSView +b.SetTitle(nst("PUSH")) // Method of NSButton +vw := win.ContentView() +vw.AddSubview(b.NSView) // Pass the button's embedded NSView +``` +In Go, `NSButtonAlloc` returns a Go object of type `ns.NSButton`. However, +there is no `InitWithFrame` method for receivers of this type. This is +not necessary because `NSButton` embeds `NSControl` which in turn embeds +`NSView`. The `InitWithFrame` method only needs to be implemented for `NSView` +receivers. Go will automatically find the indirectly embedded `NSView` and +call the right method. + +Go's type inference appears to be slightly broken (as of 1.12.1) because +the following does not work. Look out for this if you are getting type +errors: + +```go +//DO NOT DO THIS +b := ns.NSButtonAlloc().InitWithFrame(ns.MakeRect(100,100,200,200)) +//For some reason Go thinks b has type ns.NSView, because InitWithFrame is defined for ns.NSView, even though +//NSButtonAlloc() returns an ns.NSButton. +``` + +Go has no trouble finding embedded methods for your `NSButton` and will +happily search up the chain through `NSControl`, `NSView`, `NSResponder` and +`NSObject` and all of their associated protocols and categories. As of this +writing, on MacOS 10.13.6, NSWrap binds 90 instance methods for `NSObject`, +so things like `Hash()`, `IsEqualTo()`, `ClassName()` and many many +others are available and can be called on any object directly from Go. + +Go does not perform the same type +magic when you use variables as function or method parameters. +If you want to pass your `NSButton` as a parameter to a method that accepts +an `NSView` type, you need to explicitly pass the embedded `NSView` +(`b.NSView` in the example above). + +NSWrap creates a method for `Id` allowing objects to be converted +at run-time to any other class. You will need this for Enumerators, which +always return `Id`. See below under Enumerators for an example, but make +sure you know (or test) what type your objects are before converting them, +or else you will get an exception from the Objective-C runtime. + +Because `Id` can be converted to any type, and every object in the Foundation +classes inherits from `Id`, it is possible to send any message to any +object, if you are feeling lucky. You are going to have to explicitly +convert your object to the wrong type before the compiler will let you do this. + +```go +a := ns.NSArrayWithObjects(o1,o2) // NSArray embeds Id +fmt.Println(a.NSString().UTF8String()) // DON'T! +// | | \-method of NSString, returns *Char, a "Stringer" type +// | \-method of Id returning NSString +// \-calls "String()" on its parameters +``` + +The above code will compile, but you will get an exception at runtime: + +```sh +*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: +'-[__NSArrayM UTF8String]: unrecognized selector sent to instance 0x4608940' +``` + + +## Variadic Functions + +As seen above with the `NSMutableArrayWithObjects()` constructor example, +NSWrap supports variadic +functions. Because of the limitations of `cgo`, there is a numerical limit +to the number of parameters in a variadic function call, which defaults to +16 but can be set with the `vaargs` configuration directive. + +## Pointers to Pointers + +When NSWrap encounters a pointer to a pointer to an Objective-C object, it +treats it as an array of objects and translates it into a pointer to a +Go slice. If you are passing empty slices into these functions, be sure to +pre-allocate them to a sufficient size and capacity (see below for an +example). These Go slices can be used for input and output of methods and +functions. + +Pointers to pointers are sometimes passed to Objective-C methods or functions +as a way of receiving output from those functions. In those cases, after the +CGo call, the method parameter is treated as a nil-terminated array of object +pointers. The object pointers are copied into the input Go slice, which is +then truncated to the appropriate length. + +An example in Core Foundation is the `getObjects:andKeys:count` method for +`NSDictionary`: + +```go + nst := ns.NSStringWithGoString + dict := ns.NSDictionaryWithObjectsForKeys( + ns.NSArrayWithObjects(nst("obj1"),nst("obj2")), + ns.NSArrayWithObjects(nst("key1"),nst("key2")), + ) + os,ks := make([]ns.Id,0,5), make([]ns.Id,0,5) // length 0, capacity 5 slices + dict.GetObjects(&os,&ks,5) // count = 5, must be the same size or smaller than the input slice capacity + fmt.Printf("Length of os is now %d\n",len(os)) // os and ks slices are now length = 2 + for i,k := range ks { + fmt.Printf("-- %s -> %s\n",k.NSString(),os[i].NSString()) + } +``` + +Using pointers to pointers is necessary in many Core Foundation situations +where you need to get an error message out of a function or method, for example +in `[NSString stringWithContentsOfURL...]`: + +```go + err := make([]ns.NSError,1) + n1 = ns.NSStringWithContentsOfURLEncoding(ns.NSURLWithGoString("htttypo://example.com"),0,&err) + fmt.Printf("err: %s\n",err[0].LocalizedDescription()) +//err: The file couldn’t be opened because URL type htttypo isn’t supported. +``` + +## Selectors + +You can specify selectors using a Go string. The `Selector()` function +returns a Go type `SEL` which corresponds to a pointer to +`struct objc_selector` in C. +Among other things, this lets you set actions on `NSControls` and `NSMenuItems`: + +```go +appMenu.AddItemWithTitle( + ns.NSStringWithGoString("Quit"), + ns.Selector("terminate:"), + ns.NSStringWithGoString("q")) +``` + +## Enumerators + +NSWrap provides a `ForIn` method for the `NSEnumerator` type. Call it with a +`func(ns.Id) bool` parameter that returns `true` to continue and `false` to +stop the enumeration. + +```go +a := ns.NSArrayWithObjects(o1,o2,o3) +a.ObjectEnumerator().ForIn(func (o ns.Id) bool { + switch { + case o.IsKindOfClass(ns.NSStringClass()): + fmt.Println(o.NSString().UTF8String()) + return true // continue enumeration + default: + fmt.Println("Unknown class") + return false // terminate enumeration + } +}) +``` + +As seen above, you can do the usual Objective-C thing for runtime type +identification. + +## Enum Definitions + +NSWrap translates C `enum` values into Go constants. The enums you need are +specified in `nswrap.yaml` by regular expression, which, in the case of named +enums, must match the name of the `enum` itself, or in the case of anonymous +enums, must match the name of the constant(s) you are looking for as declared +within the `enum`. +The generated constants receive Go types associated with their underlying C +types, which are automatically declared by NSWrap as needed. + +The following configuration: + +```yaml +# nswrap.yaml +inputfiles: [/System/Library/Frameworks/AppKit.framework/Headers/AppKit.h] +enums: + - _CLOCK.* # match constants in an anonymous enum + - NSWindowOrdering.* # match a named enum +``` + +results in: + +```go +//ns/main.go +... +type NSWindowOrderingMode C.enum_NSWindowOrderingMode +const NSWindowAbove NSWindowOrderingMode = C.NSWindowAbove +const NSWindowBelow NSWindowOrderingMode = C.NSWindowBelow +const NSWindowOut NSWindowOrderingMode = C.NSWindowOut + +const _CLOCK_REALTIME = C._CLOCK_REALTIME +const _CLOCK_MONOTONIC = C._CLOCK_MONOTONIC +const _CLOCK_MONOTONIC_RAW = C._CLOCK_MONOTONIC_RAW +... +``` + + +## Memory management + +You can call `Retain()`, `Release()` and `Autorelease()` on any object. + +All allocation functions generated by NSWrap call `autorelease` before they +return an object. If you are not working in an environment (such as an +Application Delegate callback) that provides an autorelease pool, you can +create your own: + +* Work directly with NSAutoreleasePool objects + +```go +swamp := ns.NSAutoreleasePoolAlloc().Init() +del := ns.AppDelegateAlloc() +menu := ns.NSMenuAlloc().InitWithTitle(nst("Main")) +str := ns.NSStringWithGoString("these objects will be automatically deallocated when swamp is drained.") +... +swamp.Drain() +``` + +* ...or use the AutoreleasePool() helper function + +NSWrap provides a helper function that can be passed a `func()` with no +parameters or return value. It is conventient to give it an anonymous function +and write your code in line, just like you would if you were using an +`@autoreleasepool { }` block. + +```go +ns.AutoreleasePool(func() { + a := MyObjectAlloc().Init() + b := MyOtherObjectAlloc().Init() + ... +}) +``` + +You will need to make sure `NSAutoreleasePool` is included in the `classes` +directive in your configuration file before working with +`NSAutoreleasePool` objects or the `AutoreleasePool` helper function. + +Memory management seems to work but there ought to be a comprehensive +tests before anyone should feel confident with it. + +## Delegates + +The `delegates` directive in `nswrap.yaml` creates a new Objective-C +class and associated Go wrapper functions. For example, the following +configuration file creates a class called `CBDelegate` that implements +the Objective-C protocols `CBCentralManagerDelegate` and +`CBPeripheralDelegate`, along with the Go code you need to allocate +and use instances of the class. + +```yaml +# nswrap.yaml +inputfiles: + - /System/Library/Frameworks/CoreBluetooth.framework/Headers/CoreBluetooth.h + +classes: + - CBCentralManager + +delegates: + CBDelegate: # a name for your delegate class + CBCentralManagerDelegate: # a protocol to implement + - centralManagerDidUpdateState # messages you want to respond to + - centralManagerDidDiscoverPeripheral + - centralManagerDidConnectPeripheral + CBPeripheralDelegate: # another protocol to implement + - peripheralDidDiscoverServices + - peripheralDidDiscoverCharacteristicsForService + - peripheralDidUpdateValueForCharacteristic +... +``` + +The generated delegate inherits from NSObject and is identified as implementing +the protocols specified in `nswrap.yaml`. + +When a delegate is activated and one of the callback methods named in the +configuration file is called, the delegate will call back into an exported Go +function. If a user-defined callback function has been specified, +it will be called with all of its parameters converted to their Go type +equivalents. User-defined callbacks are registered by calling a function +with the method name in TitleCase + `Callback`, so in the example above, +call `ns.CentralManagerDidUpdateStateCallback(...)` with the name of your +callback function to register to receive notifications when your central +manager updates its state. + +The code in `examples/bluetooth` implements a working Bluetooth Low Energy +heart rate monitor entirely in Go. + +The following Go code creates a CBDelegate object in Go, +registers a callback for `centralManagerDidUpdateState`, allocates +a CBCentralManager object, and installs our delegate: + +```go +func cb(c ns.CBCentralManager) { + ... +} + +func main() { + ... + del := ns.CBDelegateAlloc() + del.CentralManagerDidUpdateStateCallback(cb) + cm := ns.CBCentralManagerAlloc().InitWithDelegateQueue(del,queue) +``` + +When you provide user-defined callback functions, you will need to specify +them with exactly the right type, +matching NSWrap's generated Go wrapper types for the callback function and +the Go types for all of its parameters. If `go build` fails, the error +messages will point you in the right direction. + +``` +$ go build +./main.go:127:43: cannot use didFinishLaunching (type func(ns.NSNotification, bool)) as type +func(ns.NSNotification) in argument to del.ApplicationDidFinishLaunchingCallback +``` +In the above example, build failed because an extra `bool` parameter was +included in the callback function. The compiler is telling you that the right +type for the callback is `func(ns.NSNotification)` with no return value. + +## Working with AppKit + +You can wrap the AppKit framework classes and create an NSApplication +Delegate. This allows you to build a Cocoa app entirely in Go. + +Because AppKit uses thread local storage, you will need to make sure all +calls into it are done from the main OS thread. This can be a challenge in +Go even though runtime.LockOSThread() is supposed to provide +this functionality. Good luck with that! + +This is actually a full working example: + +```yaml +# nswrap.yaml +inputfiles: + - /System/Library/Frameworks/AppKit.framework/Headers/AppKit.h + +classes: + - NSApplication + - NSWindow + - NSString + - NSMenu + +enums: + - NSApplication.* + - NSBackingStore.* + - NSWindowStyleMask.* + +functions: + - NSMakeRect + +delegates: + AppDelegate: + NSApplicationDelegate: + - applicationDidFinishLaunching + - applicationShouldTerminateAfterLastWindowClosed +frameworks: [ Foundation, AppKit, CoreGraphics ] +``` + +```go +//go:generate nswrap +package main + +import ( + "fmt" + "runtime" + "gitlab.wow.st/gmp/nswrap/examples/app/ns" // point to your NSWrap output directory +) + +func didFinishLaunching(n ns.NSNotification) { + fmt.Println("Go: did finish launching!") +} + +func shouldTerminate(s ns.NSApplication) ns.BOOL { + return 1 +} + +func main() { + runtime.LockOSThread() + a := ns.NSApplicationSharedApplication() + a.SetActivationPolicy(ns.NSApplicationActivationPolicyRegular) + del := ns.AppDelegateAlloc() + del.ApplicationDidFinishLaunchingCallback(didFinishLaunching) + del.ApplicationShouldTerminateAfterLastWindowClosedCallback(shouldTerminate) + a.SetDelegate(del) + + win := ns.NSWindowAlloc().InitWithContentRectStyleMask( + ns.NSMakeRect(200,200,600,600), + ns.NSWindowStyleMaskTitled | ns.NSWindowStyleMaskClosable, + ns.NSBackingStoreBuffered, + 0, + ) + win.SetTitle(ns.NSStringWithGoString("Hi World")) + win.MakeKeyAndOrderFront(win) + a.Run() +} +``` + +Pretty simple right? Not really, NSWrap just generated almost 15,000 lines of +code. See `examples/app` for a slightly more complex example with working +menus and visual format-based auto layout. + +## Subclasses + +NSWrap includes functionality to generate subclasses as specified in +`nswrap.yaml`. + +You can override existing methods or create new methods with any type +signature you specify using Objective-C method signature syntax. + +```yaml +# nswrap.yaml +... +subclasses: + myClass: # the name of the new class + yourClass: # the superclass to inherit from + - init.* # what methods to override + - -(void)hi_there:(int)x # Objective-C prototype of your new method(s) +# |--note the hyphen indicating that this is an instance method +``` + +In the example above, your new class will be named `myClass` in Objective-C +and `MyClass` in Go. It will override any `init` methods found in `yourClass` +(which must be defined in one of the header files included in the +`inputfiles` directive of `nswrap.yaml`). In addition, because the second +entry under `yourClass` starts with a `-`, it will be treated as a new +instance method definition for `myClass`. The remainder of the line will +be parsed as an Objective-C method prototype in order to determine the method +name, its return type, and the names and types of its parameters if any. + +Since multiple inheritance is not permitted in Objective-C, it is not possible +to specify more than one superclass in a `subclasses` entry. + +You can use subclasses to define new AppKit controls with configurable +callbacks. For example, lets make an `NSButton` that calls back into Go when +you press it: + +```yaml +# nswrap.yaml +... +subclasses: + GButton: + NSButton: + - -(void)pressed +... +``` + +```go +func pressed() { + fmt.Println("Button pressed!") +} +... +func didFinishLaunching(n ns.NSNotification) { + ... + button := ns.GButtonAlloc() + button.Init() + button.PressedCallback(pressed) # register user-defined callback + button.SetAction(ns.Selector("pressed")) + button.SetTarget(button) + button.SetTitle(ns.NSStringWithGoString("PUSH")) + ... +} +``` + +Later on you can add the your new button to a view and tell Cocoa where to lay +it out. It's all a little verbose, but that's because for some reason you +decided to write Objective-C code in Go. + +# Limitations + +## Blocks + +NSWrap does not support methods or functions that take C functions or blocks +as parameters or return values. + +# Why? + +Um, I was trying to make a nice modern Go binding for CoreBluetooth on MacOS +and got carried away. + +# Acknowledgements + +This work was inspired by Maxim's excellent +[c-for-go](https://github.com/xlab/c-for-go). Much of the +infrastructure was lifted from Elliot Chance's equally excellent +[c2go](https://github.com/elliotchance/c2go). Kiyoshi Murata's +post on [coderwall.com](https://coderwall.com/p/l9jr5a/accessing-cocoa-objective-c-from-go-with-cgo) +was an essential piece of inspiration. + +The combinatorial Objective-C type parsers are mine as are the +Objective-C and Go code generators, so this is where you will find +all of the bugs.