Process leader mappings on key press

[buztard]

Description

This PR has similar goals as #6580 but uses a different approach.

• Allows long timeouts and LEADER_PER_KEY_TIMING but you don't have to wait for the timeout to happen.
• Runs a user defined function on key press and after LEADER_TIMEOUT
• Allows cancellation of leader mode by key press, defaults to KC_LEAD
• No need for LEADER_EXTERNS and LEADER_DICTIONARY in user code
• Optional feature, should not interfere with the current behavior

Here's an example for a user function:

// add some configuration
#ifdef LEADER_ENABLE
#   define LEADER_ON_KEY_PROCESSING

// per key timing and and 1s timeout are vim's defaults ;)
#   define LEADER_PER_KEY_TIMING
#   define LEADER_TIMEOUT 1000

// use escape (or five invalid keypresses) to abort leader mode
#   define LEADER_ABORT KC_ESC

bool leader_process_user(uint16_t *leader_sequence, bool is_timeout) {
    SEQ_ONE_KEY(KC_S) { SEND_STRING("Leader S"); return false; } // finish processing

    // KC_G is not unique, so this one is only valid after the timeout
    SEQ_ONE_KEY(KC_G) { if (is_timeout) { SEND_STRING("Leader with shared prefix G after timeout"); return false; } }

    SEQ_TWO_KEYS(KC_G, KC_G) { SEND_STRING("Leader GG"); return false; }

    return true; // continue processing
}
#endif

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Keyboard (addition or update)
• Keymap/layout/userspace (addition or update)
• Documentation

Issues Fixed or Closed by This PR

• Closes feat: infinite timeout for leader key #6580

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• I have tested the changes and verified that they work and don't break anything (as well as I can manage).

[drashna]

I think we could just use:

Suggested change

	#if defined(LEADER_ENABLE) && defined(LEADER_ON_KEY_PROCESSING)
	#if defined(LEADER_ENABLE)

If not, it would be nice ideal if things could be changed so this is called in such a way that it could be use regardless.

[buztard]

I think this would break existing code because calling matrix_scan_leader() when on key processing is not enabled would finish the leader mode before the user gets the chance to catch it in his matrix_scan_user() with the usual LEADER_DICTIONARY() method.

However, we could move the check to into matrix_scan_leader() to keep the matrix function cleaner.

[stale]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
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[stale]

Thank you for your contribution!
This pull request has been automatically marked as stale because it has not had activity in the last 45 days. It will be closed in 30 days if no further activity occurs. Please feel free to give a status update now, or re-open when it's ready.
For maintainers: Please label with awaiting review, breaking_change, in progress, or on hold to prevent the issue from being re-flagged.

[stale]

Thank you for your contribution!
This pull request has been automatically closed because it has not had activity in the last 30 days. Please feel free to give a status update now, ping for review, or re-open when it's ready.