tapdance.c

#include QMK_KEYBOARD_H
#include "keymap.h"

static void sentence_end(tap_dance_state_t *state, void *user_data) {
    switch (state->count) {

        // Double tapping TD_DOT produces
        // ". <one-shot-shift>" i.e. dot, space and capitalize next letter.
        // This helps to quickly end a sentence and begin another one
        // without having to hit shift.
        case 2:
            /* Check that Shift is inactive */
            if (!(get_mods() & MOD_MASK_SHIFT)) {
                tap_code(KC_SPC);
                /* Internal code of OSM(MOD_LSFT) */
                add_oneshot_mods(MOD_BIT(KC_LEFT_SHIFT));

            } else {
                // send ">" (KC_DOT + shift → ">")
                tap_code(KC_DOT);
            }
            break;

        // Since `sentence_end` is called on each tap
        // and not at the end of the tapping term,
        // the third tap needs to cancel the effects
        // of the double tap in order to get the expected
        // three dots ellipsis.
        case 3:
            // remove the added space of the double tap case
            tap_code(KC_BSPC);
            // replace the space with a second dot
            tap_code(KC_DOT);
            // tap the third dot
            tap_code(KC_DOT);
            break;

        // send KC_DOT on every normal tap of TD_DOT
        default:
            tap_code(KC_DOT);
    }
};

tap_dance_action_t tap_dance_actions[] = {
    [DOT_TD] = ACTION_TAP_DANCE_FN_ADVANCED(sentence_end, NULL, NULL),
};