add flake

.gitignore

@@ -0,0 +1,8 @@
+.build
+.direnv
+.venv
+.west
+modules
+firmware
+zmk
+zephyr

Justfile

@@ -0,0 +1,91 @@
+default:
+    @just --list --unsorted
+
+config := absolute_path('config')
+build := absolute_path('.build')
+out := absolute_path('firmware')
+
+# parse combos.dtsi and adjust settings to not run out of slots
+_parse_combos:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    cconf="{{ config / 'combos.dtsi' }}"
+    if [[ -f $cconf ]]; then
+        # set MAX_COMBOS_PER_KEY to the most frequent combos count
+        count=$(
+            tail -n +10 $cconf |
+                grep -Eo '[LR][TMBH][0-9]' |
+                sort | uniq -c | sort -nr |
+                awk 'NR==1{print $1}'
+        )
+        sed -Ei "/CONFIG_ZMK_COMBO_MAX_COMBOS_PER_KEY/s/=.+/=$count/" "{{ config }}"/*.conf
+        echo "Setting MAX_COMBOS_PER_KEY to $count"
+
+        # set MAX_KEYS_PER_COMBO to the most frequent key count
+        count=$(
+            tail -n +10 $cconf |
+                grep -o -n '[LR][TMBH][0-9]' |
+                cut -d : -f 1 | uniq -c | sort -nr |
+                awk 'NR==1{print $1}'
+        )
+        sed -Ei "/CONFIG_ZMK_COMBO_MAX_KEYS_PER_COMBO/s/=.+/=$count/" "{{ config }}"/*.conf
+        echo "Setting MAX_KEYS_PER_COMBO to $count"
+    fi
+
+# parse build.yaml and filter targets by expression
+_parse_targets $expr:
+    #!/usr/bin/env bash
+    attrs="[.board, .shield]"
+    filter="(($attrs | map(. // [.]) | combinations), ((.include // {})[] | $attrs)) | join(\",\")"
+    echo "$(yq -r "$filter" build.yaml | grep -v "^," | grep -i "${expr/#all/.*}")"
+
+# build firmware for single board & shield combination
+_build_single $board $shield *west_args:
+    #!/usr/bin/env bash
+    set -euo pipefail
+    artifact="${shield:+${shield// /+}-}${board}"
+    build_dir="{{ build / '$artifact' }}"
+
+    echo "Building firmware for $artifact..."
+    west build -s zmk/app -d "$build_dir" -b $board {{ west_args }} -- \
+        -DZMK_CONFIG="{{ config }}" ${shield:+-DSHIELD="$shield"}
+
+    if [[ -f "$build_dir/zephyr/zmk.uf2" ]]; then
+        mkdir -p "{{ out }}" && cp "$build_dir/zephyr/zmk.uf2" "{{ out }}/$artifact.uf2"
+    else
+        mkdir -p "{{ out }}" && cp "$build_dir/zephyr/zmk.bin" "{{ out }}/$artifact.bin"
+    fi
+
+# build firmware for matching targets
+build expr *west_args: _parse_combos
+    #!/usr/bin/env bash
+    set -euo pipefail
+    targets=$(just _parse_targets {{ expr }})
+
+    [[ -z $targets ]] && echo "No matching targets found. Aborting..." >&2 && exit 1
+    echo "$targets" | while IFS=, read -r board shield; do
+        just _build_single "$board" "$shield" {{ west_args }}
+    done
+
+# clear build cache and artifacts
+clean:
+    rm -rf {{ build }} {{ out }}
+
+# clear all automatically generated files
+clean-all: clean
+    rm -rf .west zmk
+
+# initialize west
+init:
+    west init -l config
+    west update
+    west zephyr-export
+
+# list build targets
+list:
+    @just _parse_targets all | sed 's/,$//' | sort | column
+
+# update west
+update:
+    west update
+

README.md

@@ -43,3 +43,10 @@ Git commit and push, GH Actions will build the firmware
    ```
 
    If your keymap is correct, you will see a progress in building until it fails; otherwise, it will simply fail outright
+
+#### Build locally with nix
+
+```
+$ cd ./path_to_this_repository
+$ just build all
+```

flake.nix

@@ -0,0 +1,35 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
+
+    # Version of requirements.txt installed in pythonEnv
+    zephyr.url = "github:zephyrproject-rtos/zephyr/v3.5.0";
+    zephyr.flake = false;
+
+    # Zephyr sdk and toolchain
+    zephyr-nix.url = "github:urob/zephyr-nix";
+    zephyr-nix.inputs.zephyr.follows = "zephyr";
+
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { nixpkgs, zephyr-nix, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        zephyr = zephyr-nix.packages.${system};
+      in {
+        devShells.default = pkgs.mkShell {
+          packages = [
+            zephyr.pythonEnv
+            (zephyr.sdk.override { targets = [ "arm-zephyr-eabi" ]; })
+
+            pkgs.cmake
+            pkgs.dtc
+            pkgs.ninja
+            pkgs.qemu # needed for native_posix target
+          ];
+        };
+      });
+}
+