bind function keys (F1 to F12)

src/Window.zig

@@ -594,6 +594,18 @@ fn keyCallback(
                 .end => .end,
                 .page_up => .page_up,
                 .page_down => .page_down,
+                .F1 => .f1,
+                .F2 => .f2,
+                .F3 => .f3,
+                .F4 => .f4,
+                .F5 => .f5,
+                .F6 => .f6,
+                .F7 => .f7,
+                .F8 => .f8,
+                .F9 => .f9,
+                .F10 => .f10,
+                .F11 => .f11,
+                .F12 => .f12,
                 else => .invalid,
             },
         };

src/config.zig

@@ -94,6 +94,26 @@ pub const Config = struct {
         try result.keybind.set.put(alloc, .{ .key = .page_up }, .{ .csi = "5~" });
         try result.keybind.set.put(alloc, .{ .key = .page_down }, .{ .csi = "6~" });
 
+        // From xterm:
+        // Note that F1 through F4 are prefixed with SS3 , while the other keys are
+        // prefixed with CSI .  Older versions of xterm implement different escape
+        // sequences for F1 through F4, with a CSI  prefix.  These can be activated
+        // by setting the oldXtermFKeys resource.  However, since they do not
+        // correspond to any hardware terminal, they have been deprecated.  (The
+        // DEC VT220 reserves F1 through F5 for local functions such as Setup).
+        try result.keybind.set.put(alloc, .{ .key = .f1 }, .{ .csi = "11~" });
+        try result.keybind.set.put(alloc, .{ .key = .f2 }, .{ .csi = "12~" });
+        try result.keybind.set.put(alloc, .{ .key = .f3 }, .{ .csi = "13~" });
+        try result.keybind.set.put(alloc, .{ .key = .f4 }, .{ .csi = "14~" });
+        try result.keybind.set.put(alloc, .{ .key = .f5 }, .{ .csi = "15~" });
+        try result.keybind.set.put(alloc, .{ .key = .f6 }, .{ .csi = "17~" });
+        try result.keybind.set.put(alloc, .{ .key = .f7 }, .{ .csi = "18~" });
+        try result.keybind.set.put(alloc, .{ .key = .f8 }, .{ .csi = "19~" });
+        try result.keybind.set.put(alloc, .{ .key = .f9 }, .{ .csi = "20~" });
+        try result.keybind.set.put(alloc, .{ .key = .f10 }, .{ .csi = "21~" });
+        try result.keybind.set.put(alloc, .{ .key = .f11 }, .{ .csi = "23~" });
+        try result.keybind.set.put(alloc, .{ .key = .f12 }, .{ .csi = "24~" });
+
         return result;
     }
 };

src/input/key.zig

@@ -59,6 +59,19 @@ pub const Key = enum {
     page_up,
     page_down,
 
+    f1,
+    f2,
+    f3,
+    f4,
+    f5,
+    f6,
+    f7,
+    f8,
+    f9,
+    f10,
+    f11,
+    f12,
+
     // To support more keys (there are obviously more!) add them here
     // and ensure the mapping is up to date in the Window key handler.
 };