139 lines
3.7 KiB

""" Consumes a stream and returns a dict
However, the dict won't contain "__doc__", "___version___" etc, but
the shortened versions without underscores: "doc", "version".
Currently not supported:
* Dicts
* Floating points
* ints in list
* Strings in any other format then "x" or 'y'
* Docstrings with any other delimiter other than triple-" or triple='
* Comments
Feel free to expand if necessary
class ParseException(Exception):
"""Indicates a parsing exception"""
def __init__(self, message = ""):
def read_metadata(s):
result = {}
result["doc"] = _read_docstring(s)
while True:
key = _read_key(s)
if key:
result[key] = _read_value(s)
return result
def _read_docstring(s):
delimiter = _read_non_whitespace(s, 3)
if delimiter not in ["'''", '"""']:
raise ParseException("Docstring delimiter expected")
result = _read(s, 3);
while result[-3:] != delimiter:
result += _read(s)
return result[:-3]
def _read_value(s):
char = _read_non_whitespace(s)
return _read_value_given_first_char(s, char)
def _read_value_given_first_char(s, first_char):
if first_char in ["'", '"']:
return _read_string(s, first_char)
if first_char in "0123456789":
return _read_int(s, first_char)
if first_char in "TF":
return _read_bool(s, first_char)
if first_char == "[":
return _read_list(s)
raise ParseException("Invalid character %s found" % first_char)
def _read_string(s, delimiter):
result = _read(s)
while result[-1:] != delimiter:
result += _read(s)
except ParseException:
raise ParseException("Invalid string or not terminated: %s" % result)
return result[:-1]
def _read_int(s, char):
result = char
while not char.isspace():
char = s.read(1)
if not char:
result += char
if not char in "0123456789":
raise ParseException("Invalid int: %s" % result)
return int(result)
def _read_bool(s, char):
if char == "T":
_assert(char + _read(s, 3), "True", "Invalid boolean")
return True
_assert(char + _read(s, 4), "False", "Invalid boolean")
return False
def _read_list(s):
result = []
while True:
char = _read_non_whitespace(s)
if char == "]":
if result:
if char != ",":
raise ParseException("Expected comma, got '%s'" % char)
result.append(_read_value_given_first_char(s, char))
return result
def _read_key(s):
delimiter = _read_non_whitespace(s, 3)
if delimiter != "___":
return None
result = _read(s, 3);
while result[-3:] != delimiter:
char = _read(s)
if char in [" ", "="]:
raise ParseException()
result += char
except ParseException:
raise ParseException("Invalid key: ___%s" % result)
_assert(_read_non_whitespace(s), "=", "Expected equals")
return result[:-3]
def _read(s, l=1):
result = s.read(l)
if len(result)<l:
raise ParseException("Expected to read at least %s characters, got '%s'" % (l, result))
return result
def _assert(input, expected, message):
if not input == expected:
raise ParseException(message + " ('%s' expected, '%s' found)" % (expected, input))
def _read_non_whitespace(s, l=1):
result = s.read(1)
while result.isspace():
result = s.read(1)
if l == 1:
return result
return result + s.read(l - 1)