Align Markdown table

fix-md-table.py

#!/bin/python

import sys
import re

table: list[list[str]] = []

for line in sys.stdin.readlines():
    line = line.strip()
    if len(line) == 0:
        continue
    assert(line[0] == '|')
    row: list[str] = []
    i = 1
    while i < len(line):
        j = line.find('|', i)
        assert(j != -1)
        row.append(line[i:j].strip())
        i = j + 1
    table.append(row)

cols_count = len(table[0])
col_sizes = []
for col_idx in range(cols_count):
    col_size = 0
    for row in table:
        assert(len(row) == cols_count)
        col_size = max(col_size, len(row[col_idx]))
    col_sizes.append(col_size)

out = sys.stdout
for row in table:
    out.write("| ")
    for col_idx, col in enumerate(row):
        col_size = col_sizes[col_idx]
        align = col_size - len(col)

        fill_char = ' '
        left_align = ''
        right_align = ''

        separator = re.match(r"^\:?\-+(\:?)$", col)
        if separator:
            fill_char = '-'
            if separator.group(1) == ':':
                right_align = ':'
                col = col[:-1]

        out.write(col + fill_char * align + right_align + " |")
        if col_idx < len(row) - 1:
            out.write(' ')
    out.write('\n')