_make_iterencode.py

''' Override certain function from built-in json module to allow formatting of JSON two container types
, arrays and objects, to be optionally specified separately by allowing `indent` to be a 2-tuple.
I copied this from Python 3.5.3 but looks about the same in 3.4-3.6. Probably wont work in >=3.7.
'''

def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
        _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
        ## HACK: hand-optimized bytecode; turn globals into locals
        ValueError=ValueError,
        dict=dict,
        float=float,
        id=id,
        int=int,
        isinstance=isinstance,
        list=list,
        str=str,
        tuple=tuple,
        _intstr=int.__str__,
    ):

    _array_indent = None
    if isinstance(_indent, tuple):
        (_indent, _array_indent) = _indent
    else:
        _array_indent = _indent
    if _indent is not None and not isinstance(_indent, str):
        _indent = ' ' * _indent
    if _array_indent is not None and not isinstance(_array_indent, str):
        _array_indent = ' ' * _array_indent

    def _iterencode_list(lst, _current_indent_level):
        if not lst:
            yield '[]'
            return
        if markers is not None:
            markerid = id(lst)
            if markerid in markers:
                raise ValueError("Circular reference detected")
            markers[markerid] = lst
        buf = '['
        if _array_indent is not None:
            _current_indent_level += 1
            newline_indent = '\n' + _array_indent * _current_indent_level
            separator = _item_separator + newline_indent
            buf += newline_indent
        else:
            newline_indent = None
            separator = _item_separator
        first = True
        for value in lst:
            if first:
                first = False
            else:
                buf = separator
            if isinstance(value, str):
                yield buf + _encoder(value)
            elif value is None:
                yield buf + 'null'
            elif value is True:
                yield buf + 'true'
            elif value is False:
                yield buf + 'false'
            elif isinstance(value, int):
                # Subclasses of int/float may override __str__, but we still
                # want to encode them as integers/floats in JSON. One example
                # within the standard library is IntEnum.
                yield buf + _intstr(value)
            elif isinstance(value, float):
                # see comment above for int
                yield buf + _floatstr(value)
            else:
                yield buf
                if isinstance(value, (list, tuple)):
                    chunks = _iterencode_list(value, _current_indent_level)
                elif isinstance(value, dict):
                    chunks = _iterencode_dict(value, _current_indent_level)
                else:
                    chunks = _iterencode(value, _current_indent_level)
                yield from chunks
        if newline_indent is not None:
            _current_indent_level -= 1
            yield '\n' + _array_indent * _current_indent_level
        yield ']'
        if markers is not None:
            del markers[markerid]

    def _iterencode_dict(dct, _current_indent_level):
        if not dct:
            yield '{}'
            return
        if markers is not None:
            markerid = id(dct)
            if markerid in markers:
                raise ValueError("Circular reference detected")
            markers[markerid] = dct
        yield '{'
        if _indent is not None:
            _current_indent_level += 1
            newline_indent = '\n' + _indent * _current_indent_level
            item_separator = _item_separator + newline_indent
            yield newline_indent
        else:
            newline_indent = None
            item_separator = _item_separator
        first = True
        if _sort_keys:
            items = sorted(dct.items(), key=lambda kv: kv[0])
        else:
            items = dct.items()
        for key, value in items:
            if isinstance(key, str):
                pass
            # JavaScript is weakly typed for these, so it makes sense to
            # also allow them.  Many encoders seem to do something like this.
            elif isinstance(key, float):
                # see comment for int/float in _make_iterencode
                key = _floatstr(key)
            elif key is True:
                key = 'true'
            elif key is False:
                key = 'false'
            elif key is None:
                key = 'null'
            elif isinstance(key, int):
                # see comment for int/float in _make_iterencode
                key = _intstr(key)
            elif _skipkeys:
                continue
            else:
                raise TypeError("key " + repr(key) + " is not a string")
            if first:
                first = False
            else:
                yield item_separator
            yield _encoder(key)
            yield _key_separator
            if isinstance(value, str):
                yield _encoder(value)
            elif value is None:
                yield 'null'
            elif value is True:
                yield 'true'
            elif value is False:
                yield 'false'
            elif isinstance(value, int):
                # see comment for int/float in _make_iterencode
                yield _intstr(value)
            elif isinstance(value, float):
                # see comment for int/float in _make_iterencode
                yield _floatstr(value)
            else:
                if isinstance(value, (list, tuple)):
                    chunks = _iterencode_list(value, _current_indent_level)
                elif isinstance(value, dict):
                    chunks = _iterencode_dict(value, _current_indent_level)
                else:
                    chunks = _iterencode(value, _current_indent_level)
                yield from chunks
        if newline_indent is not None:
            _current_indent_level -= 1
            yield '\n' + _indent * _current_indent_level
        yield '}'
        if markers is not None:
            del markers[markerid]

    def _iterencode(o, _current_indent_level):
        if isinstance(o, str):
            yield _encoder(o)
        elif o is None:
            yield 'null'
        elif o is True:
            yield 'true'
        elif o is False:
            yield 'false'
        elif isinstance(o, int):
            # see comment for int/float in _make_iterencode
            yield _intstr(o)
        elif isinstance(o, float):
            # see comment for int/float in _make_iterencode
            yield _floatstr(o)
        elif isinstance(o, (list, tuple)):
            yield from _iterencode_list(o, _current_indent_level)
        elif isinstance(o, dict):
            yield from _iterencode_dict(o, _current_indent_level)
        else:
            if markers is not None:
                markerid = id(o)
                if markerid in markers:
                    raise ValueError("Circular reference detected")
                markers[markerid] = o
            o = _default(o)
            yield from _iterencode(o, _current_indent_level)
            if markers is not None:
                del markers[markerid]
    return _iterencode