Clean-room ZMK steno engine with trie/DAWG dictionary

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afiqzudinhadi 9bf21c9db2 v4 union split-section dictionary: both full dicts, zero trimming Format v4 (docs/FORMAT_V4.md): one union CHD MPHF over 226,791 stroke keys from Plover (147,424) + Lapwing (114,885), sections distributed across halves. Left blob 387KB (displacements log-class Huffman 59KB, membership 57KB, fingerprints 113KB, conflicts 9.6KB, value-index slice 157KB); right blob 515KB (strings front-coded+deflate 193KB, value-index remainder 324KB, conflicts dup). Shared string table: 73,464 unique translations, Lapwing 93% subset of Plover. - tools/compile_v4.py: encoder + full verification (all 262,309 entries byte-exact through cold decode path; hard error if either blob exceeds budget — never trims) - src/dict_v4.c/.h: decoder — canonical Huffman displacement decode, conflict binary search, FC block walk, 2-block LRU cache - src/behavior_steno.c: Plover-style sliding longest-match with retrace replaces multi-stroke timeout + prefix checks - src/split_dict.c/.h: protocol v4 — GET_STRING(string_id) / RESOLVE(slot, dict); decisions are 100% left-local, BLE only for translation text - CMake/Kconfig: STENO_DICT_BOTH default, one compiler run emits both half blobs; legacy MPHF path kept behind STENO_DICT_V4=n - Host round-trip test: 42,000 vectors left→right split path, 0 mismatches (tests/test_dict_v4.c)		2026-07-03 01:28:31 +08:00
dicts	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
dts	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
include/dt-bindings/zmk	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
src	v4 union split-section dictionary: both full dicts, zero trimming	2026-07-03 01:28:31 +08:00
tests	v4 union split-section dictionary: both full dicts, zero trimming	2026-07-03 01:28:31 +08:00
tools	v4 union split-section dictionary: both full dicts, zero trimming	2026-07-03 01:28:31 +08:00
zephyr	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
.gitignore	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
CMakeLists.txt	v4 union split-section dictionary: both full dicts, zero trimming	2026-07-03 01:28:31 +08:00
Kconfig	v4 union split-section dictionary: both full dicts, zero trimming	2026-07-03 01:28:31 +08:00
LICENSE	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00
README.md	Scaffolding: ZMK module structure, Kconfig, DTS, behavior driver	2026-07-02 02:04:28 +08:00

README.md

zmk-steno-engine

Clean-room stenography engine for ZMK Firmware. Dictionary-based lookup with multi-stroke support, optimized for nRF52840 flash constraints.

Status: Early development — basic single/multi-stroke lookup works, formatter not yet implemented.

Features

Standard 23-key steno layout
Sorted-array dictionary with binary search lookup
Multi-stroke support with configurable timeout
All-up chord detection
HID keyboard output (ASCII)
Build-time dictionary compilation from Plover JSON
Test dictionary included for development

Building

Add as a ZMK module in your west.yml:

manifest:
  remotes:
    - name: zmk-steno-engine
      url-base: https://github.com/afiqzudinhadi
  projects:
    - name: zmk-steno-engine
      remote: zmk-steno-engine
      revision: optimize-dict

Enable in your .conf:

CONFIG_STENO_ENGINE=y

Use in your keymap:

#include <dt-bindings/zmk/steno_keys.h>

/ {
    keymap {
        steno_layer {
            bindings = <
                &steno STENO_SL  &steno STENO_TL  &steno STENO_PL  ...
            >;
        };
    };
};

Dictionary Compiler

# Compile test dictionary
python3 tools/compile_simple.py dicts/test.json -o steno_dict.bin --stats

# Compile Plover dictionary (trimmed)
python3 tools/compile_simple.py plover-main.json -o steno_dict.bin --max-entries 120000 --stats

License

PolyForm Noncommercial 1.0.0