implemented tagging a client

client.c

@@ -11,44 +11,76 @@
 
 #include "dwm.h"
 
-static void (*arrange)(void *) = floating;
+static void (*arrange)(Arg *) = floating;
+
+static Client *
+next(Client *c)
+{
+	for(c = c->next; c && !c->tags[tsel]; c = c->next);
+	return c;
+}
+
+static Client *
+prev(Client *c)
+{
+	for(c = c->prev; c && !c->tags[tsel]; c = c->prev);
+	return c;
+}
 
 void
-max(void *aux)
+max(Arg *arg)
 {
-	if(!stack)
+	if(!csel)
 		return;
-	stack->x = sx;
-	stack->y = sy;
-	stack->w = sw - 2 * stack->border;
-	stack->h = sh - 2 * stack->border;
-	craise(stack);
-	resize(stack);
+	csel->x = sx;
+	csel->y = sy;
+	csel->w = sw - 2 * csel->border;
+	csel->h = sh - 2 * csel->border;
+	craise(csel);
+	resize(csel);
 	discard_events(EnterWindowMask);
 }
 
 void
-floating(void *aux)
+tag(Arg *arg)
+{
+	if(!csel)
+		return;
+
+	if(arg->i == tsel)
+		return;
+
+	if(csel->tags[arg->i])
+		csel->tags[arg->i] = NULL; /* toggle tag */
+	else
+		csel->tags[arg->i] = tags[arg->i];
+	arrange(NULL);
+}
+
+void
+floating(Arg *arg)
 {
 	Client *c;
 
 	arrange = floating;
-	for(c = stack; c; c = c->snext)
+	if(!csel)
+		return;
+	for(c = csel; c; c = next(c))
 		resize(c);
 	discard_events(EnterWindowMask);
 }
 
 void
-tiling(void *aux)
+tiling(Arg *arg)
 {
 	Client *c;
 	int n, cols, rows, gw, gh, i, j;
     float rt, fd;
 
 	arrange = tiling;
-	if(!clients)
+	if(!csel)
 		return;
-	for(n = 0, c = clients; c; c = c->next, n++);
+	for(n = 0, c = csel; c; c = next(c), n++);
 	rt = sqrt(n);
 	if(modff(rt, &fd) < 0.5)
 		rows = floor(rt);
@@ -62,7 +94,7 @@ tiling(void *aux)
 	gw = (sw - 2)  / cols;
 	gh = (sh - 2) / rows;
 
-	for(i = j = 0, c = clients; c; c = c->next) {
+	for(i = j = 0, c = csel; c; c = next(c)) {
 		c->x = i * gw;
 		c->y = j * gh;
 		c->w = gw;
@@ -77,28 +109,44 @@ tiling(void *aux)
 }
 
 void
-sel(void *aux)
+prevc(Arg *arg)
 {
-	const char *arg = aux;
-	Client *c = NULL;
+	Client *c;
 
-	if(!arg || !stack)
+	if(!csel)
 		return;
-	if(!strncmp(arg, "next", 5))
-		c = stack->snext ? stack->snext : stack;
-	else if(!strncmp(arg, "prev", 5))
-		for(c = stack; c && c->snext; c = c->snext);
-	if(!c)
-		c = stack;
+
+	if(!(c = prev(csel)))
+		c = prev(cend);
+	if(c) {
 		craise(c);
 		XWarpPointer(dpy, None, c->win, 0, 0, 0, 0, c->w / 2, c->h / 2);
 		focus(c);
+	}
 }
 
 void
-ckill(void *aux)
+nextc(Arg *arg)
 {
-	Client *c = stack;
+	Client *c;
+   
+	if(!csel)
+		return;
+
+	if(!(c = next(csel)))
+		c = next(cstart);
+
+	if(c) {
+		craise(c);
+		XWarpPointer(dpy, None, c->win, 0, 0, 0, 0, c->w / 2, c->h / 2);
+		focus(c);
+	}
+}
+
+void
+ckill(Arg *arg)
+{
+	Client *c = csel;
 
 	if(!c)
 		return;
@@ -208,19 +256,12 @@ lower(Client *c)
 void
 focus(Client *c)
 {
-	Client **l, *old;
-
-	old = stack;
-	for(l = &stack; *l && *l != c; l = &(*l)->snext);
-	if(*l)
-		*l = c->snext;
-	c->snext = stack;
-	stack = c;
-	if(old && old != c) {
-		XSetWindowBorder(dpy, old->win, dc.bg);
-		XMapWindow(dpy, old->title);
-		draw_client(old);
+	if(csel && csel != c) {
+		XSetWindowBorder(dpy, csel->win, dc.bg);
+		XMapWindow(dpy, csel->title);
+		draw_client(csel);
 	}
+	csel = c;
 	XUnmapWindow(dpy, c->title);
 	XSetWindowBorder(dpy, c->win, dc.fg);
 	draw_client(c);
@@ -232,7 +273,7 @@ focus(Client *c)
 void
 manage(Window w, XWindowAttributes *wa)
 {
-	Client *c, **l;
+	Client *c;
 	XSetWindowAttributes twa;
 
 	c = emallocz(sizeof(Client));
@@ -258,9 +299,15 @@ manage(Window w, XWindowAttributes *wa)
 			CWOverrideRedirect | CWBackPixmap | CWEventMask, &twa);
 
 	update_name(c);
-	for(l=&clients; *l; l=&(*l)->next);
-	c->next = *l; /* *l == nil */
-	*l = c;
+
+	if(!cstart)
+		cstart = cend = c;
+	else {
+		cend->next = c;
+		c->prev = cend;
+		cend = c;
+	}
+
 	XSetWindowBorderWidth(dpy, c->win, 1);
 	XMapRaised(dpy, c->win);
 	XMapRaised(dpy, c->title);
@@ -373,33 +420,42 @@ dummy_error_handler(Display *dsply, XErrorEvent *err)
 void
 unmanage(Client *c)
 {
-	Client **l;
-
 	XGrabServer(dpy);
 	XSetErrorHandler(dummy_error_handler);
 
 	XUngrabButton(dpy, AnyButton, AnyModifier, c->win);
 	XDestroyWindow(dpy, c->title);
 
-	for(l=&clients; *l && *l != c; l=&(*l)->next);
-	*l = c->next;
-	for(l=&stack; *l && *l != c; l=&(*l)->snext);
-	*l = c->snext;
+	if(c->prev) {
+		c->prev->next = c->next;
+		if(csel == c)
+			csel = c->prev;
+	}
+	if(c->next) {
+		c->next->prev = c->prev;
+		if(csel == c)
+			csel = c->next;
+	}
+	if(cstart == c)
+		cstart = c->next;
+	if(cend == c)
+		cend = c->prev;
+
 	free(c);
 
 	XFlush(dpy);
 	XSetErrorHandler(error_handler);
 	XUngrabServer(dpy);
 	arrange(NULL);
-	if(stack)
-		focus(stack);
+	if(csel)
+		focus(csel);
 }
 
 Client *
 gettitle(Window w)
 {
 	Client *c;
-	for(c = clients; c; c = c->next)
+	for(c = cstart; c; c = c->next)
 		if(c->title == w)
 			return c;
 	return NULL;
@@ -409,7 +465,7 @@ Client *
 getclient(Window w)
 {
 	Client *c;
-	for(c = clients; c; c = c->next)
+	for(c = cstart; c; c = c->next)
 		if(c->win == w)
 			return c;
 	return NULL;
@@ -419,7 +475,7 @@ void
 draw_client(Client *c)
 {
 	int i;
-	if(c == stack)
+	if(c == csel)
 		return;
 
 	dc.x = dc.y = 0;

dev.c

@@ -20,16 +20,21 @@ const char *browse[] = { "firefox", NULL };
 const char *xlock[] = { "xlock", NULL };
 
 static Key key[] = {
-	{ Mod1Mask, XK_Return, (void (*)(void *))spawn, term },
-	{ Mod1Mask, XK_w, (void (*)(void *))spawn, browse },
-	{ Mod1Mask, XK_l, (void (*)(void *))spawn, xlock },
-	{ Mod1Mask, XK_k, sel, "prev" }, 
-	{ Mod1Mask, XK_j, sel, "next" }, 
-	{ Mod1Mask, XK_t, tiling, NULL }, 
-	{ Mod1Mask, XK_f, floating, NULL }, 
-	{ Mod1Mask, XK_m, max, NULL }, 
-	{ Mod1Mask | ShiftMask, XK_c, ckill, NULL }, 
-	{ Mod1Mask | ShiftMask, XK_q, quit, NULL },
+	{ Mod1Mask, XK_Return, spawn, { .argv = term } },
+	{ Mod1Mask, XK_w, spawn, { .argv = browse } },
+	{ Mod1Mask, XK_l, spawn, { .argv = xlock } },
+	{ Mod1Mask, XK_k, prevc, { 0 } },
+	{ Mod1Mask, XK_j, nextc, { 0 } }, 
+	{ Mod1Mask, XK_t, tiling, { 0 } }, 
+	{ Mod1Mask, XK_f, floating, { 0 } }, 
+	{ Mod1Mask, XK_m, max, { 0 } }, 
+	{ Mod1Mask, XK_0, tag, { .i = Tscratch } }, 
+	{ Mod1Mask, XK_1, tag, { .i = Tdev } }, 
+	{ Mod1Mask, XK_2, tag, { .i = Tirc } }, 
+	{ Mod1Mask, XK_3, tag, { .i = Twww } }, 
+	{ Mod1Mask, XK_4, tag, { .i = Twork } }, 
+	{ Mod1Mask | ShiftMask, XK_c, ckill, { 0 } }, 
+	{ Mod1Mask | ShiftMask, XK_q, quit, { 0 } },
 };
 
 /********** CUSTOMIZE **********/
@@ -60,7 +65,7 @@ keypress(XEvent *e)
 	for(i = 0; i < len; i++)
 		if((keysym == key[i].keysym) && (key[i].mod == ev->state)) {
 			if(key[i].func)
-				key[i].func(key[i].aux);
+				key[i].func(&key[i].arg);
 			return;
 		}
 }

dwm.h

@@ -22,6 +22,12 @@ typedef struct DC DC;
 typedef struct Client Client;
 typedef struct Fnt Fnt;
 typedef struct Key Key;
+typedef union Arg Arg;
+
+union Arg {
+	const char **argv;
+	int i;
+};
 
 /* atoms */
 enum { WMProtocols, WMDelete, WMLast };
@@ -62,14 +68,14 @@ struct Client {
 	Window trans;
 	Window title;
 	Client *next;
-	Client *snext;
+	Client *prev;
 };
 
 struct Key {
 	unsigned long mod;
 	KeySym keysym;
-	void (*func)(void *aux);
-	void *aux;
+	void (*func)(Arg *arg);
+	Arg arg;
 };
 
 extern Display *dpy;
@@ -83,7 +89,7 @@ extern int tsel, screen, sx, sy, sw, sh, th;
 extern char stext[1024], *tags[TLast];
 
 extern DC dc;
-extern Client *clients, *stack;
+extern Client *cstart, *cend, *csel;
 
 /* client.c */
 extern void manage(Window w, XWindowAttributes *wa);
@@ -97,11 +103,13 @@ extern void update_size(Client *c);
 extern Client *gettitle(Window w);
 extern void craise(Client *c);
 extern void lower(Client *c);
-extern void ckill(void *aux);
-extern void sel(void *aux);
-extern void max(void *aux);
-extern void floating(void *aux);
-extern void tiling(void *aux);
+extern void ckill(Arg *arg);
+extern void nextc(Arg *arg);
+extern void prevc(Arg *arg);
+extern void max(Arg *arg);
+extern void floating(Arg *arg);
+extern void tiling(Arg *arg);
+void tag(Arg *arg);
 extern void gravitate(Client *c, Bool invert);
 
 /* draw.c */
@@ -125,7 +133,7 @@ extern void mmove(Client *c);
 extern int error_handler(Display *dsply, XErrorEvent *e);
 extern void send_message(Window w, Atom a, long value);
 extern int win_proto(Window w);
-extern void quit(void *aux);
+extern void quit(Arg *arg);
 
 /* util.c */
 extern void error(const char *errstr, ...);
@@ -133,5 +141,5 @@ extern void *emallocz(unsigned int size);
 extern void *emalloc(unsigned int size);
 extern void *erealloc(void *ptr, unsigned int size);
 extern char *estrdup(const char *str);
-extern void spawn(char *argv[]);
+extern void spawn(Arg *arg);
 extern void swap(void **p1, void **p2);

main.c

@@ -38,8 +38,9 @@ int tsel = Tdev; /* default tag */
 int screen, sx, sy, sw, sh, th;
 
 DC dc = {0};
-Client *clients = NULL;
-Client *stack = NULL;
+Client *cstart = NULL;
+Client *cend = NULL;
+Client *csel = NULL;
 
 static Bool other_wm_running;
 static const char version[] =
@@ -168,13 +169,13 @@ startup_error_handler(Display *dpy, XErrorEvent *error)
 static void
 cleanup()
 {
-	while(clients)
-		unmanage(clients);
+	while(csel)
+		unmanage(csel);
 	XSetInputFocus(dpy, PointerRoot, RevertToPointerRoot, CurrentTime);
 }
 
 void
-quit(void *aux)
+quit(Arg *arg)
 {
 	running = False;
 }

util.c

@@ -75,8 +75,9 @@ swap(void **p1, void **p2)
 }
 
 void
-spawn(char *argv[])
+spawn(Arg *arg)
 {
+	char **argv = (char **)arg->argv;
 	if(!argv || !argv[0])
 		return;
 	if(fork() == 0) {