Finished the implementation of Combobox on Mac OS X.

bleh_darwin.m

@@ -31,6 +31,11 @@ id _objc_msgSend_uint(id obj, SEL sel, uintptr_t a)
 same as above, but for NSInteger
 */
 
+intptr_t objc_msgSend_intret_noargs(id obj, SEL sel)
+{
+	return (intptr_t) ((NSInteger) objc_msgSend(obj, sel));
+}
+
 id objc_msgSend_int(id obj, SEL sel, intptr_t a)
 {
 	return objc_msgSend(obj, sel, (NSInteger) a);

objc_darwin.h

@@ -44,6 +44,8 @@ struct xsize {
 
 extern struct xsize objc_msgSend_stret_size_noargs(id obj, SEL sel);
 
+extern intptr_t objc_msgSend_intret_noargs(id obj, SEL sel);
+
 #define m1(name, type1) \
 	inline id objc_msgSend_ ## name (id obj, SEL sel, type1 a) \
 	{ \

sysdata_darwin.go

@@ -26,6 +26,7 @@ type classData struct {
 	alttextsel		C.SEL
 	append		func(id C.id, what string, alternate bool)
 	insertBefore	func(id C.id, what string, before int, alternate bool)
+	selIndex		func(id C.id) int
 	// TODO others
 	delete		func(id C.id, index int)
 }
@@ -180,6 +181,9 @@ var classTypes = [nctypes]*classData{
 				C.objc_msgSend_id_int(id, _insertItemWithTitleAtIndex, str, C.intptr_t(before))
 			}
 		},
+		selIndex:		func(id C.id) int {
+			return int(C.objc_msgSend_intret_noargs(id, _indexOfSelectedItem))
+		},
 		delete:		func(id C.id, index int) {
 			C.objc_msgSend_int(id, _removeItemAtIndex, C.intptr_t(index))
 		},
@@ -341,8 +345,13 @@ if classTypes[s.ctype].insertBefore == nil { return nil }
 }
 
 func (s *sysData) selectedIndex() int {
-	// TODO
-	return -1
+if classTypes[s.ctype].selIndex == nil { return -1 }
+	ret := make(chan int)
+	defer close(ret)
+	uitask <- func() {
+		ret <- classTypes[s.ctype].selIndex(s.id)
+	}
+	return <-ret
 }
 
 func (s *sysData) selectedIndices() []int {

todo.md

@@ -28,6 +28,7 @@ important things:
 - Cocoa coordinates have (0,0) at the bottom left: need to fix this somehow
 - I think Cocoa NSButton text is not vertically aligned properly...?
 - resizing Cocoa windows does not redraw controls correctly
+- NSComboBox scans the entered text to see if it matches one of the items and returns the index of that item if it does; find out how to suppress this so that it returns -1 unless the item was chosen from the list (like the other platforms)
 - figure out what to do about deleting a nonexistent item; each backend responds differently by default
 - there's no GTK+ error handling whatsoever; we need to figure out how it works
 - make sure GTK+ documentation point differences don't matter