backend/text_processing/parsing.py

import re


re_attention = re.compile(r"""
\\\(|
\\\)|
\\\[|
\\]|
\\\\|
\\|
\(|
\[|
:\s*([+-]?[.\d]+)\s*\)|
\)|
]|
[^\\()\[\]:]+|
:
""", re.X)

re_break = re.compile(r"\s*\bBREAK\b\s*", re.S)


def parse_prompt_attention(text):
    res = []
    round_brackets = []
    square_brackets = []

    round_bracket_multiplier = 1.1
    square_bracket_multiplier = 1 / 1.1

    def multiply_range(start_position, multiplier):
        for p in range(start_position, len(res)):
            res[p][1] *= multiplier

    for m in re_attention.finditer(text):
        text = m.group(0)
        weight = m.group(1)

        if text.startswith('\\'):
            res.append([text[1:], 1.0])
        elif text == '(':
            round_brackets.append(len(res))
        elif text == '[':
            square_brackets.append(len(res))
        elif weight is not None and round_brackets:
            multiply_range(round_brackets.pop(), float(weight))
        elif text == ')' and round_brackets:
            multiply_range(round_brackets.pop(), round_bracket_multiplier)
        elif text == ']' and square_brackets:
            multiply_range(square_brackets.pop(), square_bracket_multiplier)
        else:
            parts = re.split(re_break, text)
            for i, part in enumerate(parts):
                if i > 0:
                    res.append(["BREAK", -1])
                res.append([part, 1.0])

    for pos in round_brackets:
        multiply_range(pos, round_bracket_multiplier)

    for pos in square_brackets:
        multiply_range(pos, square_bracket_multiplier)

    if len(res) == 0:
        res = [["", 1.0]]

    i = 0
    while i + 1 < len(res):
        if res[i][1] == res[i + 1][1]:
            res[i][0] += res[i + 1][0]
            res.pop(i + 1)
        else:
            i += 1

    return res