Parse txt to blocks

Question

i have a txt file, which has the following structure

start
id=1
date=21.05.2018
summ=500
end

start
id=7
date=23.05.2018
summ=500
owner=guest
end

Answer 1

You can build a simple parser with recursion that attempts to find data between start and end blocks:

import re
class Parser:
  def __init__(self, source:str):
    self.source = iter(filter(None, source.split('\n')))
    self.results = []
    self.parse()
  @staticmethod
  def to_dict(between_blocks):
    return dict(re.split('\s*\=\s*', i) for i in between_blocks)
  def parse(self):
    _line = next(self.source, None)
    if _line is not None:
      if _line == 'start':
        scope = []
        while True:
         _temp = next(self.source, None)
         if _temp is None:
           raise Exception("Missing 'end' tag")
         if _temp != 'end':
           scope.append(_temp)
         else:
           break
        self.results.append(Parser.to_dict(filter(None, scope)))
      self.parse()
   def __repr__(self):
      return f'{Parsed}({self.results})'

print(Parser(open('filename.txt').read())).results)

Output:

[{'id': '1', 'date': '21.05.2018', 'summ': '500'}, {'id': '7', 'date': '23.05.2018', 'summ': '500', 'owner': 'guest'}]

---

Tests:

tests = [[
"""
start
id=1
date=21.05.2018
summ=500
""", Exception],
[
 """
 start
 name = someone
 age = 18
 id = 23
 end
 start
 name = someoneelse
 age = 45
 id = 55
 end
 start
 name = lastname
 age = 34
 id = 5
 end
""", None]
]
for text, is_error in tests:    
   try:
     _ = Parser(text)
   except:
     assert is_error == Exception
   else:
     assert is_error is None

print('all tests passed')

Output:

all tests passed