import re
import dataclasses


TERM_RE = re.compile(r'''([0-9][0-9/]*')?-?([0-9][0-9/]*")?''')


@dataclasses.dataclass
class Dimension:

    feet: float
    inches: float


@dataclasses.dataclass
class Scale:

    drawing: Dimension
    actual: Dimension


def parse_scale(S):
    if S.count('=') != 1:
        raise ValueError('Invalid scale pattern')
    left_term, right_term = map(str.strip, S.strip().split('='))
    dimensions = []
    for term in (left_term, right_term):
        feet_s, inches_s = TERM_RE.match(term).groups()
        feet_num_den = (feet_s or '').strip("'").split('/')
        if len(feet_num_den) == 1:
            feet = int(feet_num_den[0] or 0)
        elif len(feet_num_den) == 2:
            feet = int(feet_num_den[0]) / int(feet_num_den[1])
        inches_num_den = (inches_s or '').strip('"').split('/')
        if len(inches_num_den) == 1:
            inches = int(inches_num_den[0] or 0)
        elif len(inches_num_den) == 2:
            inches = int(inches_num_den[0]) / int(inches_num_den[1])
        dimensions.append(Dimension(feet, inches))
    return Scale(*dimensions)


tests = list(filter(None, """
1' = 1'-0"
6" = 1'-0"
3" = 1'-0"
11/2" = 1'-0"
1" = 1'-0"
3/4" = 1'-0"
1/2" = 1'-0"
3/8" = 1'-0"
1/4" = 1'-0"
3/16" = 1'-0"
""".splitlines()))


for test in tests:
    scale = parse_scale(test)
    print(f'"{test}" -> {scale}')