Added the Mac OS X implementation of messageboxes.

dialog_darwin.go

@@ -0,0 +1,52 @@
+// 2 march 2014
+package ui
+
+import (
+	// ...
+)
+
+// #cgo LDFLAGS: -lobjc -framework Foundation -framework AppKit
+// #include "objc_darwin.h"
+import "C"
+
+// NSAlert styles.
+const (
+	_NSWarningAlertStyle = 0			// default
+	_NSInformationalAlertStyle = 1
+	_NSCriticalAlertStyle = 2
+)
+
+var (
+	_NSAlert = objc_getClass("NSAlert")
+
+	_setMessageText = sel_getUid("setMessageText:")
+	_setInformativeText = sel_getUid("setInformativeText:")
+	_setAlertStyle = sel_getUid("setAlertStyle:")
+	_addButtonWithTitle = sel_getUid("addButtonWithTitle:")
+	_runModal = sel_getUid("runModal")
+)
+
+func _msgBox(title string, text string, style uintptr, button0 string) {
+	ret := make(chan struct{})
+	defer close(ret)
+	uitask <- func() {
+		box := objc_new(_NSAlert)
+		// TODO is this appropriate for title?
+		C.objc_msgSend_id(box, _setMessageText, toNSString(title))
+		C.objc_msgSend_id(box, _setInformativeText, toNSString(text))
+		objc_msgSend_uint(box, _setAlertStyle, style)
+		C.objc_msgSend_id(box, _addButtonWithTitle, toNSString(button0))
+		C.objc_msgSend_noargs(box, _runModal)
+		ret <- struct{}{}
+	}
+	<-ret
+}
+
+func msgBox(title string, text string) {
+	// TODO _NSInformationalAlertStyle?
+	_msgBox(title, text, _NSWarningAlertStyle, "OK")
+}
+
+func msgBoxError(title string, text string) {
+	_msgBox(title, text, _NSCriticalAlertStyle, "OK")
+}

uitask_darwin.go

@@ -11,10 +11,6 @@ import (
 // #include "objc_darwin.h"
 import "C"
 
-// temporary for now
-func msgBox(string, string){}
-func msgBoxError(string, string){}
-
 var uitask chan func()
 
 var (