diff --git a/redo/reredo/darwin/alloc.m b/redo/reredo/darwin/alloc.m
new file mode 100644
index 00000000..b20cd538
--- /dev/null
+++ b/redo/reredo/darwin/alloc.m
@@ -0,0 +1,84 @@
+// 4 december 2014
+#import <stdlib.h>
+#import "uipriv_darwin.h"
+
+NSMutableArray *allocations;
+
+void initAlloc(void)
+{
+	allocations = [NSMutableArray new];
+}
+
+#define UINT8(p) ((uint8_t *) (p))
+#define PVOID(p) ((void *) (p))
+#define EXTRA (sizeof (size_t) + sizeof (const char **))
+#define DATA(p) PVOID(UINT8(p) + EXTRA)
+#define BASE(p) PVOID(UINT8(p) - EXTRA)
+#define SIZE(p) ((size_t *) (p))
+#define CCHAR(p) ((const char **) (p))
+#define TYPE(p) CCHAR(UINT8(p) + sizeof (size_t))
+
+void uninitAlloc(void)
+{
+	if ([allocations count] == 0) {
+		[allocations release];
+		return;
+	}
+	fprintf(stderr, "[libui] leaked allocations:\n");
+	[allocations enumerateObjectsUsingBlock:^(id obj, NSUInteger index, BOOL *stop) {
+		NSValue *v;
+		void *ptr;
+
+		v = (NSValue *) obj;
+		ptr = [v pointerValue];
+		fprintf(stderr, "[libui] %p %s\n", ptr, *TYPE(ptr));
+	}];
+	complain("either you left something around or there's a bug in libui");
+}
+
+void *uiAlloc(size_t size, const char *type)
+{
+	void *out;
+
+	out = malloc(EXTRA + size);
+	if (out == NULL) {
+		fprintf(stderr, "memory exhausted in uiAlloc()\n");
+		abort();
+	}
+	memset(DATA(out), 0, size);
+	*SIZE(out) = size;
+	*TYPE(out) = type;
+	[allocations addObject:[NSValue valueWithPointer:out]];
+	return DATA(out);
+}
+
+void *uiRealloc(void *p, size_t new, const char *type)
+{
+	void *out;
+	size_t *s;
+
+	if (p == NULL)
+		return uiAlloc(new, type);
+	p = BASE(p);
+	out = realloc(p, EXTRA + new);
+	if (out == NULL) {
+		fprintf(stderr, "memory exhausted in uiRealloc()\n");
+		abort();
+	}
+	s = SIZE(out);
+	if (new <= *s)
+		memset(((uint8_t *) DATA(out)) + *s, 0, new - *s);
+	*s = new;
+	[allocations removeObject:[NSValue valueWithPointer:p]];
+	[allocations addObject:[NSValue valueWithPointer:out]];
+	return DATA(out);
+}
+
+void uiFree(void *p)
+{
+	if (p == NULL)
+		complain("attempt to uiFree(NULL); there's a bug somewhere");
+	p = BASE(p);
+	free(p);
+	[allocations removeObject:[NSValue valueWithPointer:p]];
+}
diff --git a/redo/reredo/darwin/main.m b/redo/reredo/darwin/main.m
new file mode 100644
index 00000000..172e5844
--- /dev/null
+++ b/redo/reredo/darwin/main.m
@@ -0,0 +1,110 @@
+// 6 april 2015
+#import "uipriv_darwin.h"
+
+static BOOL canQuit = NO;
+
+@implementation applicationClass
+
+// hey look! we're overriding terminate:!
+// we're going to make sure we can go back to main() whether Cocoa likes it or not!
+// and just how are we going to do that, hm?
+// (note: this is called after applicationShouldTerminate:)
+- (void)terminate:(id)sender
+{
+	// yes that's right folks: DO ABSOLUTELY NOTHING.
+	// the magic is [NSApp run] will just... stop.
+
+	// well let's not do nothing; let's actually quit our graceful way
+	NSEvent *e;
+
+	// for debugging
+	NSLog(@"in terminate:");
+
+	if (!canQuit)
+		complain("call to [NSApp terminate:] when not ready to terminate");
+
+	[realNSApp() stop:realNSApp()];
+	// stop: won't register until another event has passed; let's synthesize one
+	e = [NSEvent otherEventWithType:NSApplicationDefined
+		location:NSZeroPoint
+		modifierFlags:0
+		timestamp:[[NSProcessInfo processInfo] systemUptime]
+		windowNumber:0
+		context:[NSGraphicsContext currentContext]
+		subtype:0
+		data1:0
+		data2:0];
+	[realNSApp() postEvent:e atStart:NO];		// let pending events take priority (this is what PostQuitMessage() on Windows does so we have to do it here too for parity; thanks to mikeash in irc.freenode.net/#macdev for confirming that this parameter should indeed be NO)
+}
+
+@end
+
+@implementation appDelegate
+
+- (void)dealloc
+{
+	[self.menuManager release];
+	[super dealloc];
+}
+
+- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)app
+{
+	// for debugging
+	NSLog(@"in applicationShouldTerminate:");
+	if (shouldQuit()) {
+		canQuit = YES;
+		// this will call terminate:, which is the same as uiQuit()
+		return NSTerminateNow;
+	}
+	return NSTerminateCancel;
+}
+
+- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication *)app
+{
+	return NO;
+}
+
+@end
+
+uiInitOptions options;
+
+const char *uiInit(uiInitOptions *o)
+{
+	options = *o;
+	[applicationClass sharedApplication];
+	// don't check for a NO return; something (launch services?) causes running from application bundles to always return NO when asking to change activation policy, even if the change is to the same activation policy!
+	// see https://github.com/andlabs/ui/issues/6
+	[realNSApp() setActivationPolicy:NSApplicationActivationPolicyRegular];
+	[realNSApp() setDelegate:[appDelegate new]];
+
+	initAlloc();
+
+	// always do this so we always have an application menu
+	appDelegate().menuManager = [menuManager new];
+	[realNSApp() setMainMenu:[appDelegate().menuManager makeMenubar]];
+
+	return NULL;
+}
+
+void uiUninit(void)
+{
+	uninitMenus();
+	// TODO free application delegate
+	// TODO free NSApplication resources (main menu, etc.)
+	uninitAlloc();
+}
+
+void uiFreeInitError(const char *err)
+{
+}
+
+void uiMain(void)
+{
+	[realNSApp() run];
+}
+
+void uiQuit(void)
+{
+	canQuit = YES;
+	[realNSApp() terminate:realNSApp()];
+}
diff --git a/redo/reredo/darwin/stddialogs.m b/redo/reredo/darwin/stddialogs.m
new file mode 100644
index 00000000..7890ad55
--- /dev/null
+++ b/redo/reredo/darwin/stddialogs.m
@@ -0,0 +1,24 @@
+// 26 june 2015
+#import "uipriv_darwin.h"
+
+char *uiOpenFile(void)
+{
+	// TODO
+	return NULL;
+}
+
+char *uiSaveFile(void)
+{
+	// TODO
+	return NULL;
+}
+
+void uiMsgBox(const char *title, const char *description)
+{
+	// TODO
+}
+
+void uiMsgBoxError(const char *title, const char *description)
+{
+	// TODO
+}
diff --git a/redo/reredo/darwin/text.m b/redo/reredo/darwin/text.m
new file mode 100644
index 00000000..f0d3dab6
--- /dev/null
+++ b/redo/reredo/darwin/text.m
@@ -0,0 +1,19 @@
+// 10 april 2015
+#import "uipriv_darwin.h"
+
+char *uiDarwinNSStringToText(NSString *s)
+{
+	char *out;
+
+	out = strdup([s UTF8String]);
+	if (out == NULL) {
+		fprintf(stderr, "memory exhausted in uiDarwinNSStringToText()\n");
+		abort();
+	}
+	return out;
+}
+
+void uiFreeText(char *s)
+{
+	free(s);
+}
diff --git a/redo/reredo/darwin/util.m b/redo/reredo/darwin/util.m
new file mode 100644
index 00000000..37af7c58
--- /dev/null
+++ b/redo/reredo/darwin/util.m
@@ -0,0 +1,56 @@
+// 7 april 2015
+#import "uipriv_darwin.h"
+
+// also fine for NSCells and NSTexts (NSTextViews)
+void setStandardControlFont(NSControl *control)
+{
+	[control setFont:[NSFont systemFontOfSize:[NSFont systemFontSizeForControlSize:NSRegularControlSize]]];
+}
+
+void disableAutocorrect(NSTextView *tv)
+{
+	[tv setEnabledTextCheckingTypes:0];
+	[tv setAutomaticDashSubstitutionEnabled:NO];
+	// don't worry about automatic data detection; it won't change stringValue (thanks pretty_function in irc.freenode.net/#macdev)
+	[tv setAutomaticSpellingCorrectionEnabled:NO];
+	[tv setAutomaticTextReplacementEnabled:NO];
+	[tv setAutomaticQuoteSubstitutionEnabled:NO];
+	[tv setAutomaticLinkDetectionEnabled:NO];
+	[tv setSmartInsertDeleteEnabled:NO];
+}
+
+void complain(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	fprintf(stderr, "[libui] ");
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+	va_end(ap);
+	abort();
+}
+
+// These are based on measurements from Interface Builder.
+// These seem to be based on Auto Layout constants, but I don't see an API that exposes these...
+// This one is 8 for most pairs of controls that I've tried; the only difference is between two pushbuttons, where it's 12...
+#define macXPadding 8
+// Likewise, this one appears to be 12 for pairs of push buttons...
+#define macYPadding 8
+
+uiSizing *uiDarwinNewSizing(void)
+{
+	uiSizing *d;
+
+	d = uiNew(uiSizing);
+	d->XPadding = macXPadding;
+	d->YPadding = macYPadding;
+	d->Sys = uiNew(uiSizingSys);
+	return d;
+}
+
+void uiFreeSizing(uiSizing *d)
+{
+	uiFree(d->Sys);
+	uiFree(d);
+}
diff --git a/redo/reredo/menu.c b/redo/reredo/menu.c
new file mode 100644
index 00000000..917e4eaf
--- /dev/null
+++ b/redo/reredo/menu.c
@@ -0,0 +1,19 @@
+// 29 may 2015
+#include "ui.h"
+
+static uintmax_t type_uiMenu = 0;
+static uintmax_t type_uiMenuItem = 0;
+
+uintmax_t uiTypeMenu(void)
+{
+	if (type_uiMenu == 0)
+		type_uiMenu = uiRegisterType("uiMenu", 0, 0);
+	return type_uiMenu;
+}
+
+uintmax_t uiTypeMenuItem(void)
+{
+	if (type_uiMenuItem == 0)
+		type_uiMenuItem = uiRegisterType("uiMenuItem", 0, 0);
+	return type_uiMenuItem;
+}
diff --git a/redo/reredo/ptrarray.c b/redo/reredo/ptrarray.c
new file mode 100644
index 00000000..45d36f67
--- /dev/null
+++ b/redo/reredo/ptrarray.c
@@ -0,0 +1,49 @@
+// 5 may 2015
+#include <string.h>
+#include "ui.h"
+#include "uipriv.h"
+
+struct ptrArray *newPtrArray(void)
+{
+	return uiNew(struct ptrArray);
+}
+
+void ptrArrayDestroy(struct ptrArray *p)
+{
+	if (p->len != 0)
+		complain("attempt to destroy ptrarray %p while it still has pointers inside", p);
+	if (p->ptrs != NULL)			// array was created but nothing was ever put inside
+		uiFree(p->ptrs);
+	uiFree(p);
+}
+
+#define grow 32
+
+void ptrArrayAppend(struct ptrArray *p, void *d)
+{
+	ptrArrayInsertAt(p, p->len, d);
+}
+
+void ptrArrayInsertAt(struct ptrArray *p, uintmax_t i, void *d)
+{
+	if (i > p->len)
+		complain("index out of range in ptrArrayInsertAt()");
+	if (p->len >= p->cap) {
+		p->cap += grow;
+		p->ptrs = (void **) uiRealloc(p->ptrs, p->cap * sizeof (void *), "void *[]");
+	}
+	// thanks to ValleyBell
+	memmove(&(p->ptrs[i + 1]), &(p->ptrs[i]), (p->len - i) * sizeof (void *));
+	p->ptrs[i] = d;
+	p->len++;
+}
+
+void ptrArrayDelete(struct ptrArray *p, uintmax_t i)
+{
+	if (i >= p->len)
+		complain("index out of range in ptrArrayRemove()");
+	// thanks to ValleyBell
+	memmove(&(p->ptrs[i]), &(p->ptrs[i + 1]), (p->len - i - 1) * sizeof (void *));
+	p->ptrs[p->len - 1] = NULL;
+	p->len--;
+}
diff --git a/redo/reredo/shouldquit.c b/redo/reredo/shouldquit.c
new file mode 100644
index 00000000..27805df8
--- /dev/null
+++ b/redo/reredo/shouldquit.c
@@ -0,0 +1,22 @@
+// 9 may 2015
+#include "ui.h"
+#include "uipriv.h"
+
+static int defaultOnShouldQuit(void *data)
+{
+	return 0;
+}
+
+static int (*onShouldQuit)(void *) = defaultOnShouldQuit;
+static void *onShouldQuitData;
+
+void uiOnShouldQuit(int (*f)(void *), void *data)
+{
+	onShouldQuit = f;
+	onShouldQuitData = data;
+}
+
+int shouldQuit(void)
+{
+	return (*onShouldQuit)(onShouldQuitData);
+}
diff --git a/redo/reredo/types.c b/redo/reredo/types.c
new file mode 100644
index 00000000..62fe1543
--- /dev/null
+++ b/redo/reredo/types.c
@@ -0,0 +1,88 @@
+// 17 may 2015
+#include "ui.h"
+#include "uipriv.h"
+
+struct typeinfo {
+	const char *name;
+	uintmax_t parent;
+	size_t size;
+};
+
+static struct ptrArray *types = NULL;
+
+uintmax_t uiRegisterType(const char *name, uintmax_t parent, size_t size)
+{
+	struct typeinfo *ti;
+
+	if (types == NULL) {
+		types = newPtrArray();
+		// reserve ID 0
+		ptrArrayAppend(types, NULL);
+	}
+	// TODO prevent our size from being smaller than our parent's
+	ti = uiNew(struct typeinfo);
+	ti->name = name;
+	ti->parent = parent;
+	ti->size = size;
+	ptrArrayAppend(types, ti);
+	return types->len - 1;
+}
+
+void *uiIsA(void *p, uintmax_t id, int fail)
+{
+	uiTyped *t;
+	struct typeinfo *ti, *ti2;
+	uintmax_t compareTo;
+
+	if (id == 0 || id >= types->len)
+		complain("invalid type ID given to uiIsA()");
+	t = (uiTyped *) p;
+	compareTo = t->Type;
+	if (compareTo == 0)
+		complain("object %p has no type in uiIsA()", t);
+	for (;;) {
+		if (compareTo >= types->len)
+			complain("invalid type ID in uiIsA()", t);
+		if (compareTo == id)
+			return t;
+		ti = ptrArrayIndex(types, struct typeinfo *, compareTo);
+		if (ti->parent == 0)
+			break;
+		compareTo = ti->parent;
+	}
+	if (fail) {
+		ti = ptrArrayIndex(types, struct typeinfo *, id);
+		ti2 = ptrArrayIndex(types, struct typeinfo *, t->Type);
+		complain("object %p not a %s in uiIsA() (is a %s)", t, ti->name, ti2->name);
+	}
+	return NULL;
+}
+
+void uninitTypes(void)
+{
+	struct typeinfo *ti;
+
+	if (types == NULL)		// never initialized; do nothing
+		return;
+	// the first entry is NULL; get rid of it directly
+	ptrArrayDelete(types, 0);
+	while (types->len != 0) {
+		ti = ptrArrayIndex(types, struct typeinfo *, 0);
+		ptrArrayDelete(types, 0);
+		uiFree(ti);
+	}
+	ptrArrayDestroy(types);
+}
+
+uiTyped *newTyped(uintmax_t type)
+{
+	struct typeinfo *ti;
+	uiTyped *instance;
+
+	if (type == 0 || type >= types->len)
+		complain("invalid type ID given to newTyped()");
+	ti = ptrArrayIndex(types, struct typeinfo *, type);
+	instance = (uiTyped *) uiAlloc(ti->size, ti->name);
+	instance->Type = type;
+	return instance;
+}