Added code comments to parse_chf.

matemat/webserver/util.py

@@ -168,21 +168,27 @@ def parse_chf(value: str) -> int:
     :return: An integer representation of the value.
     :raises: Value error: If more than two digits after the decimal point are present.
     """
+    # Remove optional leading "CHF" and strip whitespace
     value = value.strip()
     if value.startswith('CHF'):
         value = value[3:]
     value = value.strip()
     if '.' not in value:
+        # already is an integer; parse and turn into centimes
         return int(value, 10) * 100
+    # Split at the decimal point
     full, frac = value.split('.', 1)
     if len(frac) > 2:
         raise ValueError('Needs max. 2 digits after decimal point')
     elif len(frac) < 2:
+        # Right-pad fraction with zeros ("x." -> "x.00", "x.x" -> "x.x0")
         frac = frac + '0' * (2 - len(frac))
+    # Parse both parts
     ifrac: int = int(frac, 10)
     ifull: int = int(full, 10)
     if ifrac < 0:
         raise ValueError('Fraction part must not be negative.')
     if full.startswith('-'):
         ifrac = -ifrac
+    # Combine into centime integer
     return ifull * 100 + ifrac