neo2koy.py

#!/usr/bin/python3
#
# Script to transform the latest NEO2-layout for macos to a similar layout,
# such as KOY.  It swaps the keycodes to the corresponding ones and leaves
# the rest of the file as it is.  I use it to generate a KOY layout from
# the latest NEO2 upstream at
#
#   https://git.neo-layout.org/neo/neo-layout/src/branch/master/mac_osx/neo-layouts.bundle/Contents/Resources/Deutsch%20%28Neo%202%29.keylayout
#
# Other layouts such as bone, mine etc. could be generated as well.
# Layers 4, 6, 8 and 9 are left untouched.
#

import re
import sys

neo2koy = {
    '0': '5',
    '5': '14',
    '14': '31',
    '31': '39',
    '39': '17',
    '17': '43',
    '43': '15',
    '15': '34',
    '34': '32',
    '32': '0',

    '1': '3',
    '3': '2',
    '2': '1',

    '4': '41',
    '41': '4',

    '6': '9',
    '9': '46',
    '46': '47',
    '47': '13',
    '13': '16',
    '16': '12',
    '12': '6',

    '7': '11',
    '11': '33',
    '33': '35',
    '35': '7',

    '37': '38',
    '38': '37',
}

def transform(input, output, target, debug=False):
    layers = {}
    current_layer = None
    buffer = []

    with open(input) as f:
        for n, line in enumerate(f):

            original_line = line
            line = line.strip()

            if line.startswith('<keyboard group="'):
                new_line = re.sub(r'Deutsch \(Neo 2\)', r'Deutsch (KOY)', original_line, count=1)
                buffer.append(new_line)
                continue
            elif line.startswith('<keyMap index="'):
                m = re.search(r'<keyMap index="(\d+)"', line)
                if m:
                    layer = m.group(1)
                    if debug: print(f"layer {layer} starts at line {n}: {line}")
                    if layer in ['4', '6', '8', '9']:
                        # skip layers that should remain the same
                        if debug: print(f"leaving layer {layer} as it is")
                    else:
                        layers[layer] = {}
                        current_layer = layer
                else:
                    print(f"ERROR: no layer index found at line {n}: {line}!", file=sys.stderr)
                    sys.exit(1)

                buffer.append(original_line)
                continue
            elif line.startswith('</keyMap>'):
                if current_layer is not None:
                    # write collected and modified keymaps for layer
                    s = sorted(layers[current_layer], key=int)
                    for i in s:
                        if debug: print(f"i: {i}, line: {layers[current_layer][i].strip()}")
                        buffer.append(layers[current_layer][i])

                buffer.append(original_line)
                current_layer = None
                continue

            if current_layer is not None:
                m = re.search(r'<key code="(\d+)"', line)
                if m:
                    code = m.group(1)
                else:
                    print(f"ERROR: no code found at line {n}: {line}!", file=sys.stderr)
                    sys.exit(1)

                if code in target:
                    if debug: print(f"substituting code '{code}' to '{target[code]}' in line {n}: {line}")

                    new_line = re.sub(code, target[code], original_line, count=1)

                    if debug: print(f"result: {new_line.strip()}")

                    layers[current_layer][target[code]] = new_line
                else:
                    layers[current_layer][code] = original_line
            else:
                buffer.append(original_line)

    with open(output, 'w') as f:
        f.writelines(buffer)


if __name__ == '__main__':
    transform('Deutsch (Neo 2).keylayout', 'koy.keylayout', neo2koy, debug=False)