ptal parsing routine

parse_ptal.py

from random import shuffle
from typing import Tuple, Set, Optional, List
from itertools import dropwhile, takewhile, tee


_PLEADS = [
    'meow',
    'ptal',
    # etc
]

_MODIFIERS = ['!', '?']


def _get_modifier(word: str) -> Optional[str]:
    if word[-1] in _MODIFIERS:
        return word[-1]
    return None


def _is_plead(word: str) -> bool:
    if _get_modifier(word):
        word = word[:-1]

    return word.lower() in _PLEADS


_is_not_plead = lambda w: not _is_plead(w)


def _parse_ptal_group(modifier: Optional[str], words: List[str]) -> Tuple[Set[str], Set[str]]:
    mentions = [w for w in words if w.startswith('@')]

    if not mentions:
        return set(), set()
    elif not modifier:
        return set(), set(mentions)
    elif modifier == '!':
        return set(mentions), set()
    elif modifier == '?':
        shuffle(mentions)
        return {mentions[0]}, set(mentions[1:])

    raise Exception('unrecognized modifier: {}'.format(modifier))


def _parse_ptal_line(line: str) -> Tuple[Set[str], Set[str]]:
    words = [w.strip() for w in line.split()]

    assignees = set()  # type: Set[str]
    reviewers = set()  # type: Set[str]

    i = dropwhile(_is_not_plead, words)

    while True:
        try:
            plead_word = next(i)
        except StopIteration:
            break

        assert _is_plead(plead_word), plead_word

        i, j = tee(i)
        group_words = list(takewhile(_is_not_plead, j))

        for _ in group_words:
            next(i)

        aa, rr = _parse_ptal_group(_get_modifier(plead_word), group_words)
        assignees, reviewers = assignees.union(aa), reviewers.union(rr)

    return assignees, reviewers


def parse_ptal(text: str) -> Tuple[Set[str], Set[str]]:

    assignees = set()  # type: Set[str]
    reviewers = set()  # type: Set[str]

    # Go over all lines and aggregate them
    for line in text.split('\n'):
        aa, rr = _parse_ptal_line(line)
        assignees, reviewers = assignees.union(aa), reviewers.union(rr)

    return assignees, reviewers


def test():
    print('testing')
    print(parse_ptal(''))
    print(parse_ptal('meow'))
    print(parse_ptal('meow @logan'))
    print(parse_ptal('meow @logan @zimmer'))
    print(parse_ptal('meow! @logan @zimmer'))
    print(parse_ptal('meow? @logan @zimmer'))
    print(parse_ptal('meow? @logan @zimmer ptal @john'))
    print(parse_ptal('meow? @logan @zimmer ptal @john @zumi'))
    print(parse_ptal('meow! @logan @zimmer\nptal? @john @zumi'))


test()