Started rewriting the OS X backend. This time I start by writing the controls how I'd ideally write the boilerplate.

redo/reredo/darwin/button.m

@@ -0,0 +1,116 @@
+// 13 august 2015
+#import "uipriv_darwin.h"
+
+struct uiButton {
+	uiDarwinControl c;
+	NSButton *button;
+	void (*onClicked)(uiButton *, void *);
+	void *onClickedData;
+};
+
+@interface buttonDelegateClass : NSObject {
+	NSMutableDictionary *buttons;
+}
+- (IBAction)onClicked:(id)sender;
+- (void)registerButton:(uiButton *)b;
+- (void)unregisterButton:(uiButton *)b;
+@end
+
+@implementation buttonDelegateClass
+
+- (id)init
+{
+	self = [super init];
+	if (self)
+		self->buttons = [NSMutableDictionary new];
+	return self;
+}
+
+- (void)dealloc
+{
+	if ([self->buttons count] != 0)
+		complain("attempt to destroy shared button delegate but buttons are still registered to it");
+	[self->buttons release];
+	[super dealloc];
+}
+
+- (IBAction)onClicked:(id)sender
+{
+	NSValue *v;
+	uiButton *b;
+
+	v = (NSValue *) [self->buttons objectForKey:sender];
+	b = (uiButton *) [v pointerValue];
+	(*(b->onClicked))(b, b->onClickedData);
+}
+
+- (void)registerButton:(uiButton *)b
+{
+	[self->buttons setObject:[NSValue valueWithPointer:b]
+		forKey:b->button];
+	[b->button setTarget:self];
+	[b->button setAction:@selector(onClicked:)];
+}
+
+- (void)unregisterButton:(uiButton *)b
+{
+	[b->button setTarget:nil];
+	[self->buttons removeObjectForKey:b->button];
+}
+
+@end
+
+static buttonDelegateClass *buttonDelegate = nil;
+
+uiDarwinDefineControlWithOnDestroy(
+	uiButton,								// type name
+	uiButtonType,							// type function
+	button,								// handle
+	[buttonDelegate unregisterButton:this];		// on destroy
+)
+
+char *uiButtonText(uiButton *b)
+{
+	return uiDarwinNSStringToText([b->button title]);
+}
+
+void uiButtonSetText(uiButton *b, const char *text)
+{
+	[b->button setTitle:toNSString(text)];
+	// this may result in the size of the button changing
+	uiControlQueueResize(uiControl(b));
+}
+
+void uiButtonOnClicked(uiButton *b, void (*f)(uiButton *, void *), void *data)
+{
+	b->onClicked = f;
+	b->onClickedData = NULL;
+}
+
+static void defaultOnClicked(uiButton *b, void *data)
+{
+	// do nothing
+}
+
+uiButton *uiNewButton(const char *text)
+{
+	uiButton *b;
+
+	b = (uiButton *) uiNewControl(uiButtonType());
+
+	b->button = [[NSButton alloc] initWithFrame:NSZeroRect];
+	[b->button setTitle:toNSString(text)];
+	[b->button setButtonType:NSMomentaryPushInButton];
+	[b->button setBordered:YES];
+	[b->button setBezelStyle:NSRoundedBezelStyle];
+	uiDarwinSetControlFont(b->button, NSControlSizeRegular);
+
+	if (buttonDelegate == nil)
+		buttonDelegate = [buttonDelegateClass new];
+	[buttonDelegate registerButton:b];
+	uiButtonOnClicked(b, defaultOnClicked, NULL);
+
+	uiDarwinFinishNewControl(b, uiButton);
+
+	return b;
+}