Support zipped data files

It should be possible to read data from zipped CSV files and write data to zipped files transparently. I.e. something along the lines of

looking up fname.parent / (fname.name + '.zip') here:

csvw/src/csvw/metadata.py

Lines 645 to 672 in 58be38c

    
               def iterdicts(self, log=None, with_metadata=False, fname=None, _Row=collections.OrderedDict): 
        
                   """Iterate over the rows of the table 
        
                   Create an iterator that maps the information in each row to a `dict` whose keys are 
        
                   the column names of the table and whose values are the values in the corresponding 
        
                   table cells, or for virtual columns (which have no values) the valueUrl for that 
        
                   column. This includes columns not specified in the table specification. 
        
                   :param log: Logger object (default None) The object that reports parsing errors.\ 
        
                   If none is given, parsing errors raise ValueError instead. 
        
                   :param bool with_metadata: (default False) Also yield fname and lineno 
        
                   :param fname: file-like, pathlib.Path, or str (default None)\ 
        
                   The file to be read. Defaults to inheriting from a parent object, if one exists. 
        
                   :return: A generator of dicts or triples (fname, lineno, dict) if with_metadata 
        
                   """ 
        
                   dialect = self._get_dialect() 
        
                   fname = fname or self.url.resolve(self.base) 
        
                   colnames, virtualcols, requiredcols = [], [], set() 
        
                   for col in self.tableSchema.columns: 
        
                       if col.virtual: 
        
                           if col.valueUrl: 
        
                               virtualcols.append((col.header, col.valueUrl)) 
        
                       else: 
        
                           colnames.append(col.header) 
        
                       if col.required: 
        
                           requiredcols.add(col.header) 
        
                   with UnicodeReaderWithLineNumber(fname, dialect=dialect) as reader:

supporting a zip=False keyword argument here

csvw/src/csvw/metadata.py

Line 598 in 58be38c

def write(self, items, fname=DEFAULT, base=None):

	def iterdicts(self, log=None, with_metadata=False, fname=None, _Row=collections.OrderedDict):
	"""Iterate over the rows of the table

	Create an iterator that maps the information in each row to a `dict` whose keys are
	the column names of the table and whose values are the values in the corresponding
	table cells, or for virtual columns (which have no values) the valueUrl for that
	column. This includes columns not specified in the table specification.

	:param log: Logger object (default None) The object that reports parsing errors.\
	If none is given, parsing errors raise ValueError instead.
	:param bool with_metadata: (default False) Also yield fname and lineno
	:param fname: file-like, pathlib.Path, or str (default None)\
	The file to be read. Defaults to inheriting from a parent object, if one exists.
	:return: A generator of dicts or triples (fname, lineno, dict) if with_metadata
	"""
	dialect = self._get_dialect()
	fname = fname or self.url.resolve(self.base)
	colnames, virtualcols, requiredcols = [], [], set()
	for col in self.tableSchema.columns:
	if col.virtual:
	if col.valueUrl:
	virtualcols.append((col.header, col.valueUrl))
	else:
	colnames.append(col.header)
	if col.required:
	requiredcols.add(col.header)

	with UnicodeReaderWithLineNumber(fname, dialect=dialect) as reader: