[Python-Dev] nondist/sandbox/typecheck

[Paul Prescod]

Could I check in some type-checking code into nondist/sandbox? It's
quickly getting to the point where real users can start to see benefits
from it and I would like to let people play with it to convince
themselves of that.

Consider these mistaken statements:

os.path.abspath(None)
xmllib.XMLParser().feed(None)
sre.compile(".*", "I")

Here's what we used to get as tracebacks:

	os.path.abspath(None)
	(no error, any falsible value is treated as the same as the empty
string!)

	xmllib.XMLParser().feed(None)

Traceback (most recent call last):
  File "errors.py", line 8, in ?
    xmllib.XMLParser().feed(None)
  File "c:\python20\lib\xmllib.py", line 164, in feed
    self.rawdata = self.rawdata + data
TypeError: cannot add type "None" to string

	sre.compile(".*", "I")

Traceback (most recent call last):
  File "errors.py", line 12, in ?
    sre.compile(".*", "I")
  File "c:\python20\lib\sre.py", line 62, in compile
    return _compile(pattern, flags)
  File "c:\python20\lib\sre.py", line 100, in _compile
    p = sre_compile.compile(pattern, flags)
  File "c:\python20\lib\sre_compile.py", line 359, in compile
    p = sre_parse.parse(p, flags)
  File "c:\python20\lib\sre_parse.py", line 586, in parse
    p = _parse_sub(source, pattern, 0)
  File "c:\python20\lib\sre_parse.py", line 294, in _parse_sub
    items.append(_parse(source, state))
  File "c:\python20\lib\sre_parse.py", line 357, in _parse
    if state.flags & SRE_FLAG_VERBOSE:
TypeError: bad operand type(s) for &

====================

Here's what we get now:

	os.path.abspath(None)

Traceback (most recent call last):
  File "errors.py", line 4, in ?
    os.path.abspath(None)
  File "ntpath.py", line 401, in abspath
    def abspath(path):
InterfaceError: Parameter 'path' expected Unicode or 8-bit string.
Instead it got 'None' (None)

	xmllib.XMLParser().feed(None)

Traceback (most recent call last):
  File "errors.py", line 8, in ?
    xmllib.XMLParser().feed(None)
  File "xmllib.py", line 163, in feed
    def feed(self, data):
InterfaceError: Parameter 'data' expected Unicode or 8-bit string.
Instead it got 'None' (None)

	sre.compile(".*", "I")

Traceback (most recent call last):
  File "errors.py", line 12, in ?
    sre.compile(".*", "I")
  File "sre.py", line 61, in compile
    def compile(pattern, flags=0):
InterfaceError: Parameter 'flags' expected None.
Instead it got 'string' ('I')
None

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