genstrings_swift.py

import re
import os
import io
import argparse
from collections import namedtuple

OUTPUT_FILE = 'Localizable_swift.strings'
OUTPUT_ENCODING = 'utf-16'
OUTPUT_LINE_PATTERN = u'/* {comment} */\n"{key}" = "{value}";\n\n'
EMPTY_COMMENT = u'No comment provided by engineer.'


string_pattern = re.compile('NSLocalizedString\(\s*(.+)\)', re.MULTILINE)
empty_pattern = re.compile('"([^"]*)"')
key_pattern = re.compile('key:\s*"([^"]*)"')
value_pattern = re.compile('value:\s*"([^"]*)"')
comment_pattern = re.compile('comment:\s*"([^"]*)"')
var_pattern = re.compile('%(.)')
String = namedtuple('String', ['key', 'value', 'comment'])


def read_cmd():
    parser = argparse.ArgumentParser()
    parser.add_argument('-o', '--output', help='Command output directory', default='.')
    parser.add_argument('filepaths', help='file(s) to generate strings from', type=argparse.FileType('r'), nargs='+')
    args = parser.parse_args()
    return args


def replace_vars(value):
    var_result = list(var_pattern.finditer(value))
    if len(var_result) > 1:
        for idx, result in enumerate(var_result):
            value = value.replace(result.group(0), '%{}${}'.format(idx + 1, result.group(1)), 1)
    return value


def generate_string(params):
    key_result = key_pattern.search(params)
    if key_result:
        key = key_result.group(1)
    else:
        key_result = empty_pattern.match(params)
        if key_result:
            key = key_result.group(1)
        else:
            print("can't resolve parameters for %s" % match.group(0))

    value_result = value_pattern.search(params)
    if value_result:
        value = value_result.group(1)
    else:
        value = key
    value = replace_vars(value)

    comment_result = comment_pattern.search(params)
    if comment_result:
        comment = comment_result.group(1) or EMPTY_COMMENT
    else:
        comment = EMPTY_COMMENT

    return String(key, value, comment)


def grep_file(filepaths):
    strings = []
    for filepath in filepaths:
        with io.open(filepath.name, encoding='utf-8') as fp:
			content = fp.read()
			for match in string_pattern.finditer(content):
				params = match.group(1)
				string = generate_string(params)
				strings.append(string)
    return strings


def save_strings(output_dir, strings):
    filepath = os.path.join(output_dir, OUTPUT_FILE)
    with io.open(filepath, 'w', encoding=OUTPUT_ENCODING) as fp:
        output_lines = map(lambda s: OUTPUT_LINE_PATTERN.format(**s._asdict()), strings)
        fp.writelines(output_lines)


def main():
    args = read_cmd()
    strings = grep_file(args.filepaths)
    save_strings(args.output, strings)



if __name__ == '__main__':
    main()