1 files changed, 31 insertions, 0 deletions

diff --git a/users/callum/oneshot.h b/users/callum/oneshot.h
new file mode 100644
index 000000000..a6b8e1774
--- /dev/null
+++ b/users/callum/oneshot.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include QMK_KEYBOARD_H
+
+// Represents the four states a oneshot key can be in
+typedef enum {
+    os_up_unqueued,
+    os_up_queued,
+    os_down_unused,
+    os_down_used,
+} oneshot_state;
+
+// Custom oneshot mod implementation that doesn't rely on timers. If a mod is
+// used while it is held it will be unregistered on keyup as normal, otherwise
+// it will be queued and only released after the next non-mod keyup.
+void update_oneshot(
+    oneshot_state *state,
+    uint16_t mod,
+    uint16_t trigger,
+    uint16_t keycode,
+    keyrecord_t *record
+);
+
+// To be implemented by the consumer. Defines keys to cancel oneshot mods.
+bool is_oneshot_cancel_key(uint16_t keycode);
+
+// To be implemented by the consumer. Defines keys to ignore when determining
+// whether a oneshot mod has been used. Setting this to modifiers and layer
+// change keys allows stacking multiple oneshot modifiers, and carrying them
+// between layers.
+bool is_oneshot_ignored_key(uint16_t keycode);