From e8b312c6e3035560a14789db1a7d47410b62a710 Mon Sep 17 00:00:00 2001
From: Noah Osterholz <osterholznoah@gmail.com>
Date: Fri, 6 Mar 2026 11:32:03 +0100
Subject: [PATCH] Adding conditional keybinding support.

This patch adds the conditional function to change the behaviour
of a keymap depending on the return value of another function.
---
 config.def.h |  9 ++++++++-
 dwm.c        | 21 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/config.def.h b/config.def.h
index 81c3fc0..c1112c9 100644
--- a/config.def.h
+++ b/config.def.h
@@ -61,6 +61,13 @@ static char dmenumon[2] = "0"; /* component of dmenucmd, manipulated in spawn()
 static const char *dmenucmd[] = { "dmenu_run", "-m", dmenumon, "-fn", dmenufont, "-nb", col_gray1, "-nf", col_gray3, "-sb", col_cyan, "-sf", col_gray4, NULL };
 static const char *termcmd[]  = { "st", NULL };
 
+/* condition functions */
+static int 
+isrootwindow(void)
+{
+  return (selmon->sel == NULL); /* selmon->sel == NULL -> root window focused */
+}
+
 static const Key keys[] = {
 	/* modifier                     key        function        argument */
 	{ MODKEY,                       XK_p,      spawn,          {.v = dmenucmd } },
@@ -74,7 +81,7 @@ static const Key keys[] = {
 	{ MODKEY,                       XK_l,      setmfact,       {.f = +0.05} },
 	{ MODKEY,                       XK_Return, zoom,           {0} },
 	{ MODKEY,                       XK_Tab,    view,           {0} },
-	{ MODKEY|ShiftMask,             XK_c,      killclient,     {0} },
+  { MODKEY|ShiftMask,             XK_c,      conditional,    {.v = &(CondFuncPtr){isrootwindow, quit, killclient, {0}, {0} } } },
 	{ MODKEY,                       XK_t,      setlayout,      {.v = &layouts[0]} },
 	{ MODKEY,                       XK_f,      setlayout,      {.v = &layouts[1]} },
 	{ MODKEY,                       XK_m,      setlayout,      {.v = &layouts[2]} },
diff --git a/dwm.c b/dwm.c
index 0a67103..a2dc2f1 100644
--- a/dwm.c
+++ b/dwm.c
@@ -140,6 +140,14 @@ typedef struct {
 	int monitor;
 } Rule;
 
+typedef struct {
+  int (*condition)(void);
+  void (*func_true)(const Arg *arg);
+  void (*func_false)(const Arg *arg);
+  const Arg arg_true;
+  const Arg arg_false;
+} CondFuncPtr;
+
 /* function declarations */
 static void applyrules(Client *c);
 static int applysizehints(Client *c, int *x, int *y, int *w, int *h, int interact);
@@ -152,6 +160,7 @@ static void checkotherwm(void);
 static void cleanup(void);
 static void cleanupmon(Monitor *mon);
 static void clientmessage(XEvent *e);
+static void conditional(const Arg *arg);
 static void configure(Client *c);
 static void configurenotify(XEvent *e);
 static void configurerequest(XEvent *e);
@@ -977,6 +986,18 @@ grabkeys(void)
 	}
 }
 
+void
+conditional(const Arg *arg)
+{
+	CondFuncPtr *conditional = (CondFuncPtr*)arg->v;
+	if (conditional->condition() && conditional->func_true != NULL) {
+		conditional->func_true(&(conditional->arg_true));
+		return;
+	} else if (conditional->func_false != NULL) {
+	  conditional->func_false(&(conditional->arg_false));
+  }
+}
+
 void
 incnmaster(const Arg *arg)
 {
-- 
2.53.0