Chordal Hold: restrict what chords settle as hold

quantum/action_tapping.c

@@ -49,6 +49,47 @@ __attribute__((weak)) bool get_permissive_hold(uint16_t keycode, keyrecord_t *re
 }
 #    endif
 
+#    ifdef CHORDAL_HOLD
+__attribute__((weak)) bool get_chordal_hold(
+        uint16_t tap_hold_keycode, keyrecord_t* tap_hold_record,
+        uint16_t other_keycode, keyrecord_t* other_record) {
+    return get_chordal_hold_default(tap_hold_record, other_record);
+}
+
+bool get_chordal_hold_default(
+        keyrecord_t* tap_hold_record, keyrecord_t* other_record) {
+    uint8_t tap_hold_hand = chordal_hold_handedness_user(tap_hold_record->event.key);
+    if (tap_hold_hand == 0) {
+        return true;
+    }
+    uint8_t other_hand = chordal_hold_handedness_user(other_record->event.key);
+    return other_hand == 0 || tap_hold_hand != other_hand;
+}
+
+__attribute__((weak)) uint8_t chordal_hold_handedness_kb(keypos_t key) {
+#        if defined(SPLIT_KEYBOARD) || ((MATRIX_ROWS) > (MATRIX_COLS))
+#pragma message "Inferred handedness rows"
+    // If the keyboard is split or if MATRIX_ROWS > MATRIX_COLS, assume that the
+    // first half of the rows are left and the latter half are right.
+    return (key.row < (MATRIX_ROWS) / 2) ? /*left*/ 1 : /*right*/ 2;
+#        else
+#pragma message "Inferred handedness cols"
+    // Otherwise, assume the first half of the cols are left, others are right.
+    return (key.col < (MATRIX_COLS) / 2) ? /*left*/ 1 : /*right*/ 2;
+#        endif
+}
+
+__attribute__((weak)) uint8_t chordal_hold_handedness_user(keypos_t key) {
+#        if defined(CHORDAL_HOLD_LAYOUT)
+#        pragma message "Using chordal_hold_layout"
+    // If given, read handedness from `chordal_hold_layout` array.
+    return pgm_read_byte(&chordal_hold_layout[key.row][key.col]);
+#        else
+    return chordal_hold_handedness_kb(key);
+#        endif
+}
+#    endif  // CHORDAL_HOLD
+
 #    ifdef HOLD_ON_OTHER_KEY_PRESS_PER_KEY
 __attribute__((weak)) bool get_hold_on_other_key_press(uint16_t keycode, keyrecord_t *record) {
     return false;
@@ -188,7 +229,7 @@ bool process_tapping(keyrecord_t *keyp) {
         return true;
     }
 
-#    if (defined(AUTO_SHIFT_ENABLE) && defined(RETRO_SHIFT)) || defined(PERMISSIVE_HOLD_PER_KEY) || defined(HOLD_ON_OTHER_KEY_PRESS_PER_KEY)
+#    if (defined(AUTO_SHIFT_ENABLE) && defined(RETRO_SHIFT)) || defined(PERMISSIVE_HOLD_PER_KEY) || defined(CHORDAL_HOLD) || defined(HOLD_ON_OTHER_KEY_PRESS_PER_KEY)
     TAP_DEFINE_KEYCODE;
 #    endif
 
@@ -271,6 +312,22 @@ bool process_tapping(keyrecord_t *keyp) {
                     // set interrupted flag when other key pressed during tapping
                     if (event.pressed) {
                         tapping_key.tap.interrupted = true;
+
+#   if defined(CHORDAL_HOLD)
+                        if (!is_tap_record(keyp) &&
+                            !get_chordal_hold(tapping_keycode, &tapping_key,
+                                    get_record_keycode(keyp, true), keyp)) {
+                            // Settle the tapping key as *tapped*, since it is
+                            // not considered a held chord with keyp.
+                            ac_dprintf("Tapping: End. Tap in non-chord\n");
+                            tapping_key.tap.count = 1;
+                            // In process_action(), HOLD_ON_OTHER_KEY_PRESS will
+                            // revert interrupted events to holds, so this needs
+                            // to be set false.
+                            tapping_key.tap.interrupted = false;
+                            process_record(&tapping_key);
+                        } else
+#    endif
                         if (TAP_GET_HOLD_ON_OTHER_KEY_PRESS
 #    if defined(AUTO_SHIFT_ENABLE) && defined(RETRO_SHIFT)
                             // Auto Shift cannot evaluate this early
@@ -278,6 +335,8 @@ bool process_tapping(keyrecord_t *keyp) {
                             && !(MAYBE_RETRO_SHIFTING(event, keyp) && get_auto_shifted_key(get_record_keycode(keyp, false), keyp))
 #    endif
                         ) {
+                            // Settle the tapping key as *held*, since
+                            // HOLD_ON_OTHER_KEY_PRESS is enabled for this key.
                             ac_dprintf("Tapping: End. No tap. Interfered by pressed key\n");
                             process_record(&tapping_key);
                             tapping_key = (keyrecord_t){0};

quantum/action_tapping.h

@@ -46,6 +46,82 @@ bool     get_permissive_hold(uint16_t keycode, keyrecord_t *record);
 bool     get_retro_tapping(uint16_t keycode, keyrecord_t *record);
 bool     get_hold_on_other_key_press(uint16_t keycode, keyrecord_t *record);
 
+#ifdef CHORDAL_HOLD
+/**
+ * Callback to say when a key chord before the tapping term is considered held.
+ *
+ * In keymap.c, define the callback
+ *
+ *     bool get_chordal_hold(uint16_t tap_hold_keycode,
+ *                           keyrecord_t* tap_hold_record,
+ *                           uint16_t other_keycode,
+ *                           keyrecord_t* other_record) {
+ *        // Conditions...
+ *     }
+ *
+ * This callback is called when:
+ *
+ * 1. `tap_hold_keycode` is pressed.
+ * 2. `other_keycode` is pressed while `tap_hold_keycode` is still held,
+ *     provided `other_keycode` is *not* also a tap-hold key and it is pressed
+ *     before the tapping term.
+ *
+ * Returning true indicates that the tap-hold key should be considered held, or
+ * false to consider it tapped.
+ *
+ * @param tap_hold_keycode   Keycode of the tap-hold key.
+ * @param tap_hold_record    Record from the tap-hold press event.
+ * @param other_keycode      Keycode of the other key.
+ * @param other_record       Record from the other key's press event.
+ * @return True if the tap-hold key is considered held; false if tapped.
+ */
+bool get_chordal_hold(
+    uint16_t tap_hold_keycode, keyrecord_t* tap_hold_record,
+    uint16_t other_keycode, keyrecord_t* other_record);
+
+/**
+ * Default "opposite hands rule" for whether a key chord should settle as held.
+ *
+ * This function returns true when the tap-hold key and other key are on
+ * "opposite hands." In detail, handedness of the two keys are compared. If
+ * handedness values differ, or if either handedness is zero, the function
+ * returns true, indicating a hold. Otherwise, it returns false, indicating that
+ * the tap-hold key should settle as tapped.
+ *
+ * "Handedness" is determined as follows, in order of decending precedence:
+ * 1. `chordal_hold_handedness_user()`, if defined.
+ * 2. `chordal_hold_layout`, if CHORDAL_HOLD_LAYOUT is defined.
+ * 3. `chordal_hold_handedness_kb()`, if defined.
+ * 4. fallback assumption based on keyboard matrix dimensions.
+ *
+ * @param tap_hold_record  Record of the active tap-hold key press.
+ * @param other_record     Record of the other, interrupting key press.
+ * @return True if the tap-hold key is considered held; false if tapped.
+ */
+bool get_chordal_hold_default(
+    keyrecord_t* tap_hold_record, keyrecord_t* other_record);
+
+/**
+ * Keyboard-level callback to determine handedness of a key.
+ *
+ * This function should return:
+ *   1 for keys pressed by the left hand,
+ *   2 for keys on the right hand,
+ *   0 for keys exempt from the "opposite hands rule." This could be used
+ *     perhaps on thumb keys or keys that might be pressed by either hand.
+ *
+ * @param key   A key matrix position.
+ * @return Handedness value.
+ */
+uint8_t chordal_hold_handedness_kb(keypos_t key);
+/** User callback to determine handedness of a key. */
+uint8_t chordal_hold_handedness_user(keypos_t key);
+
+#    ifdef CHORDAL_HOLD_LAYOUT
+extern const uint8_t chordal_hold_layout[MATRIX_ROWS][MATRIX_COLS] PROGMEM;
+#    endif
+#endif
+
 #ifdef DYNAMIC_TAPPING_TERM_ENABLE
 extern uint16_t g_tapping_term;
 #endif

tests/tap_hold_configurations/chordal_hold/config.h

@@ -0,0 +1,21 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+#define CHORDAL_HOLD
+

tests/tap_hold_configurations/chordal_hold/test.mk

@@ -0,0 +1,18 @@
+# Copyright 2022 Vladislav Kucheriavykh
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------

tests/tap_hold_configurations/chordal_hold/test_tap_hold.cpp

@@ -0,0 +1,167 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class ChordalHold : public TestFixture {};
+
+TEST_F(ChordalHold, chord_with_mod_tap_settled_as_hold) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    // Regular key on the right hand.
+    auto       regular_key      = KeymapKey(0, MATRIX_COLS - 1, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_A));
+    regular_key.press();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    regular_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHold, non_chord_with_mod_tap_settled_as_tap) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key and regular key both on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_REPORT(driver, (KC_P, KC_A));
+    regular_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    regular_key.release();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHold, tap_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM - 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHold, hold_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHold, chordal_hold_ignores_multiple_mod_taps) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_key1 = KeymapKey(0, 1, 0, SFT_T(KC_A));
+    auto       mod_tap_key2 = KeymapKey(0, 2, 0, RSFT_T(KC_B));
+
+    set_keymap({mod_tap_key1, mod_tap_key2});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key1.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press second mod-tap key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_RIGHT_SHIFT));
+    mod_tap_key2.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release keys. */
+    EXPECT_REPORT(driver, (KC_RIGHT_SHIFT));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key1.release();
+    run_one_scan_loop();
+    mod_tap_key2.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+

tests/tap_hold_configurations/chordal_hold_and_hold_on_other_key_press/config.h

@@ -0,0 +1,22 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+#define CHORDAL_HOLD
+#define HOLD_ON_OTHER_KEY_PRESS
+

tests/tap_hold_configurations/chordal_hold_and_hold_on_other_key_press/test.mk

@@ -0,0 +1,18 @@
+# Copyright 2022 Vladislav Kucheriavykh
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------

tests/tap_hold_configurations/chordal_hold_and_hold_on_other_key_press/test_tap_hold.cpp

@@ -0,0 +1,167 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class ChordalHoldAndHoldOnOtherKeypress : public TestFixture {};
+
+TEST_F(ChordalHoldAndHoldOnOtherKeypress, chord_with_mod_tap_settled_as_hold) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    // Regular key on the right hand.
+    auto       regular_key      = KeymapKey(0, MATRIX_COLS - 1, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_A));
+    regular_key.press();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    regular_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndHoldOnOtherKeypress, non_chord_with_mod_tap_settled_as_tap) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key and regular key both on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_REPORT(driver, (KC_P, KC_A));
+    regular_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    regular_key.release();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndHoldOnOtherKeypress, tap_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM - 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndHoldOnOtherKeypress, hold_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndHoldOnOtherKeypress, chordal_hold_ignores_multiple_mod_taps) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_key1 = KeymapKey(0, 1, 0, SFT_T(KC_A));
+    auto       mod_tap_key2 = KeymapKey(0, 2, 0, RSFT_T(KC_B));
+
+    set_keymap({mod_tap_key1, mod_tap_key2});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key1.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press second mod-tap key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_RIGHT_SHIFT));
+    mod_tap_key2.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release keys. */
+    EXPECT_REPORT(driver, (KC_RIGHT_SHIFT));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key1.release();
+    run_one_scan_loop();
+    mod_tap_key2.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+

tests/tap_hold_configurations/chordal_hold_and_permissive_hold/config.h

@@ -0,0 +1,22 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "test_common.h"
+#define CHORDAL_HOLD
+#define PERMISSIVE_HOLD
+

tests/tap_hold_configurations/chordal_hold_and_permissive_hold/test.mk

@@ -0,0 +1,18 @@
+# Copyright 2022 Vladislav Kucheriavykh
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# --------------------------------------------------------------------------------
+# Keep this file, even if it is empty, as a marker that this folder contains tests
+# --------------------------------------------------------------------------------

tests/tap_hold_configurations/chordal_hold_and_permissive_hold/test_tap_hold.cpp

@@ -0,0 +1,167 @@
+/* Copyright 2022 Vladislav Kucheriavykh
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "keyboard_report_util.hpp"
+#include "keycode.h"
+#include "test_common.hpp"
+#include "action_tapping.h"
+#include "test_fixture.hpp"
+#include "test_keymap_key.hpp"
+
+using testing::_;
+using testing::InSequence;
+
+class ChordalHoldAndPermissiveHold : public TestFixture {};
+
+TEST_F(ChordalHoldAndPermissiveHold, chord_with_mod_tap_settled_as_hold) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    // Regular key on the right hand.
+    auto       regular_key      = KeymapKey(0, MATRIX_COLS - 1, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_A));
+    regular_key.press();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    regular_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndPermissiveHold, non_chord_with_mod_tap_settled_as_tap) {
+    TestDriver driver;
+    InSequence s;
+    // Mod-tap key and regular key both on the left hand.
+    auto       mod_tap_hold_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+    auto       regular_key      = KeymapKey(0, 2, 0, KC_A);
+
+    set_keymap({mod_tap_hold_key, regular_key});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_hold_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_REPORT(driver, (KC_P, KC_A));
+    regular_key.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release regular key. */
+    EXPECT_REPORT(driver, (KC_P));
+    regular_key.release();
+    idle_for(TAPPING_TERM);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release mod-tap-hold key. */
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_hold_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndPermissiveHold, tap_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM - 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_REPORT(driver, (KC_P));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndPermissiveHold, hold_mod_tap_key) {
+    TestDriver driver;
+    InSequence s;
+    auto mod_tap_key = KeymapKey(0, 1, 0, SFT_T(KC_P));
+
+    set_keymap({mod_tap_key});
+
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    mod_tap_key.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+
+TEST_F(ChordalHoldAndPermissiveHold, chordal_hold_ignores_multiple_mod_taps) {
+    TestDriver driver;
+    InSequence s;
+    auto       mod_tap_key1 = KeymapKey(0, 1, 0, SFT_T(KC_A));
+    auto       mod_tap_key2 = KeymapKey(0, 2, 0, RSFT_T(KC_B));
+
+    set_keymap({mod_tap_key1, mod_tap_key2});
+
+    /* Press mod-tap-hold key. */
+    EXPECT_NO_REPORT(driver);
+    mod_tap_key1.press();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+
+    /* Press second mod-tap key. */
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT));
+    EXPECT_REPORT(driver, (KC_LEFT_SHIFT, KC_RIGHT_SHIFT));
+    mod_tap_key2.press();
+    idle_for(TAPPING_TERM + 1);
+    VERIFY_AND_CLEAR(driver);
+
+    /* Release keys. */
+    EXPECT_REPORT(driver, (KC_RIGHT_SHIFT));
+    EXPECT_EMPTY_REPORT(driver);
+    mod_tap_key1.release();
+    run_one_scan_loop();
+    mod_tap_key2.release();
+    run_one_scan_loop();
+    VERIFY_AND_CLEAR(driver);
+}
+