toml.py

"""Python module which parses and emits TOML.

Released under the MIT license.
"""
import re
import io
import datetime
from os import linesep
import sys

__version__ = "0.9.6"
_spec_ = "0.4.0"


class TomlDecodeError(Exception):
    """Base toml Exception / Error."""
    pass


class TomlTz(datetime.tzinfo):
    def __init__(self, toml_offset):
        if toml_offset == "Z":
            self._raw_offset = "+00:00"
        else:
            self._raw_offset = toml_offset
        self._sign = -1 if self._raw_offset[0] == '-' else 1
        self._hours = int(self._raw_offset[1:3])
        self._minutes = int(self._raw_offset[4:6])

    def tzname(self, dt):
        return "UTC" + self._raw_offset

    def utcoffset(self, dt):
        return self._sign * datetime.timedelta(hours=self._hours,
                                               minutes=self._minutes)

    def dst(self, dt):
        return datetime.timedelta(0)


class InlineTableDict(object):
    """Sentinel subclass of dict for inline tables."""


def _get_empty_inline_table(_dict):
    class DynamicInlineTableDict(_dict, InlineTableDict):
        """Concrete sentinel subclass for inline tables.
        It is a subclass of _dict which is passed in dynamically at load time
        It is also a subclass of InlineTableDict
        """

    return DynamicInlineTableDict()


try:
    _range = xrange
except NameError:
    unicode = str
    _range = range
    basestring = str
    unichr = chr

try:
    FNFError = FileNotFoundError
except NameError:
    FNFError = IOError


def load(f, _dict=dict):
    """Parses named file or files as toml and returns a dictionary

    Args:
        f: Path to the file to open, array of files to read into single dict
           or a file descriptor
        _dict: (optional) Specifies the class of the returned toml dictionary

    Returns:
        Parsed toml file represented as a dictionary

    Raises:
        TypeError -- When f is invalid type
        TomlDecodeError: Error while decoding toml
        IOError / FileNotFoundError -- When an array with no valid (existing)
        (Python 2 / Python 3)          file paths is passed
    """

    if isinstance(f, basestring):
        with io.open(f, encoding='utf-8') as ffile:
            return loads(ffile.read(), _dict)
    elif isinstance(f, list):
        from os import path as op
        from warnings import warn
        if not [path for path in f if op.exists(path)]:
            error_msg = "Load expects a list to contain filenames only."
            error_msg += linesep
            error_msg += ("The list needs to contain the path of at least one "
                          "existing file.")
            raise FNFError(error_msg)
        d = _dict()
        for l in f:
            if op.exists(l):
                d.update(load(l))
            else:
                warn("Non-existent filename in list with at least one valid "
                     "filename")
        return d
    else:
        try:
            return loads(f.read(), _dict)
        except AttributeError:
            raise TypeError("You can only load a file descriptor, filename or "
                            "list")


_groupname_re = re.compile(r'^[A-Za-z0-9_-]+$')


def loads(s, _dict=dict):
    """Parses string as toml

    Args:
        s: String to be parsed
        _dict: (optional) Specifies the class of the returned toml dictionary

    Returns:
        Parsed toml file represented as a dictionary

    Raises:
        TypeError: When a non-string is passed
        TomlDecodeError: Error while decoding toml
    """

    implicitgroups = []
    retval = _dict()
    currentlevel = retval
    if not isinstance(s, basestring):
        raise TypeError("Expecting something like a string")

    if not isinstance(s, unicode):
        s = s.decode('utf8')

    sl = list(s)
    openarr = 0
    openstring = False
    openstrchar = ""
    multilinestr = False
    arrayoftables = False
    beginline = True
    keygroup = False
    keyname = 0
    for i, item in enumerate(sl):
        if item == '\r' and sl[i + 1] == '\n':
            sl[i] = ' '
            continue
        if keyname:
            if item == '\n':
                raise TomlDecodeError("Key name found without value."
                                      " Reached end of line.")
            if openstring:
                if item == openstrchar:
                    keyname = 2
                    openstring = False
                    openstrchar = ""
                continue
            elif keyname == 1:
                if item.isspace():
                    keyname = 2
                    continue
                elif item.isalnum() or item == '_' or item == '-':
                    continue
            elif keyname == 2 and item.isspace():
                continue
            if item == '=':
                keyname = 0
            else:
                raise TomlDecodeError("Found invalid character in key name: '" +
                                      item + "'. Try quoting the key name.")
        if item == "'" and openstrchar != '"':
            k = 1
            try:
                while sl[i - k] == "'":
                    k += 1
                    if k == 3:
                        break
            except IndexError:
                pass
            if k == 3:
                multilinestr = not multilinestr
                openstring = multilinestr
            else:
                openstring = not openstring
            if openstring:
                openstrchar = "'"
            else:
                openstrchar = ""
        if item == '"' and openstrchar != "'":
            oddbackslash = False
            k = 1
            tripquote = False
            try:
                while sl[i - k] == '"':
                    k += 1
                    if k == 3:
                        tripquote = True
                        break
                if k == 1 or (k == 3 and tripquote):
                    while sl[i - k] == '\\':
                        oddbackslash = not oddbackslash
                        k += 1
            except IndexError:
                pass
            if not oddbackslash:
                if tripquote:
                    multilinestr = not multilinestr
                    openstring = multilinestr
                else:
                    openstring = not openstring
            if openstring:
                openstrchar = '"'
            else:
                openstrchar = ""
        if item == '#' and (not openstring and not keygroup and
                            not arrayoftables):
            j = i
            try:
                while sl[j] != '\n':
                    sl[j] = ' '
                    j += 1
            except IndexError:
                break
        if item == '[' and (not openstring and not keygroup and
                            not arrayoftables):
            if beginline:
                if len(sl) > i + 1 and sl[i + 1] == '[':
                    arrayoftables = True
                else:
                    keygroup = True
            else:
                openarr += 1
        if item == ']' and not openstring:
            if keygroup:
                keygroup = False
            elif arrayoftables:
                if sl[i - 1] == ']':
                    arrayoftables = False
            else:
                openarr -= 1
        if item == '\n':
            if openstring or multilinestr:
                if not multilinestr:
                    raise TomlDecodeError("Unbalanced quotes")
                if ((sl[i - 1] == "'" or sl[i - 1] == '"') and (
                        sl[i - 2] == sl[i - 1])):
                    sl[i] = sl[i - 1]
                    if sl[i - 3] == sl[i - 1]:
                        sl[i - 3] = ' '
            elif openarr:
                sl[i] = ' '
            else:
                beginline = True
        elif beginline and sl[i] != ' ' and sl[i] != '\t':
            beginline = False
            if not keygroup and not arrayoftables:
                if sl[i] == '=':
                    raise TomlDecodeError("Found empty keyname. ")
                keyname = 1
    s = ''.join(sl)
    s = s.split('\n')
    multikey = None
    multilinestr = ""
    multibackslash = False
    for line in s:
        if not multilinestr or multibackslash or '\n' not in multilinestr:
            line = line.strip()
        if line == "" and (not multikey or multibackslash):
            continue
        if multikey:
            if multibackslash:
                multilinestr += line
            else:
                multilinestr += line
            multibackslash = False
            if len(line) > 2 and (line[-1] == multilinestr[0] and
                                  line[-2] == multilinestr[0] and
                                  line[-3] == multilinestr[0]):
                try:
                    value, vtype = _load_value(multilinestr, _dict)
                except ValueError as err:
                    raise TomlDecodeError(str(err))
                currentlevel[multikey] = value
                multikey = None
                multilinestr = ""
            else:
                k = len(multilinestr) - 1
                while k > -1 and multilinestr[k] == '\\':
                    multibackslash = not multibackslash
                    k -= 1
                if multibackslash:
                    multilinestr = multilinestr[:-1]
                else:
                    multilinestr += "\n"
            continue
        if line[0] == '[':
            arrayoftables = False
            if len(line) == 1:
                raise TomlDecodeError("Opening key group bracket on line by "
                                      "itself.")
            if line[1] == '[':
                arrayoftables = True
                line = line[2:]
                splitstr = ']]'
            else:
                line = line[1:]
                splitstr = ']'
            i = 1
            quotesplits = _get_split_on_quotes(line)
            quoted = False
            for quotesplit in quotesplits:
                if not quoted and splitstr in quotesplit:
                    break
                i += quotesplit.count(splitstr)
                quoted = not quoted
            line = line.split(splitstr, i)
            if len(line) < i + 1 or line[-1].strip() != "":
                raise TomlDecodeError("Key group not on a line by itself.")
            groups = splitstr.join(line[:-1]).split('.')
            i = 0
            while i < len(groups):
                groups[i] = groups[i].strip()
                if len(groups[i]) > 0 and (groups[i][0] == '"' or
                                           groups[i][0] == "'"):
                    groupstr = groups[i]
                    j = i + 1
                    while not groupstr[0] == groupstr[-1]:
                        j += 1
                        if j > len(groups) + 2:
                            raise TomlDecodeError("Invalid group name '" +
                                                  groupstr + "' Something " +
                                                  "went wrong.")
                        groupstr = '.'.join(groups[i:j]).strip()
                    groups[i] = groupstr[1:-1]
                    groups[i + 1:j] = []
                else:
                    if not _groupname_re.match(groups[i]):
                        raise TomlDecodeError("Invalid group name '" +
                                              groups[i] + "'. Try quoting it.")
                i += 1
            currentlevel = retval
            for i in _range(len(groups)):
                group = groups[i]
                if group == "":
                    raise TomlDecodeError("Can't have a keygroup with an empty "
                                          "name")
                try:
                    currentlevel[group]
                    if i == len(groups) - 1:
                        if group in implicitgroups:
                            implicitgroups.remove(group)
                            if arrayoftables:
                                raise TomlDecodeError("An implicitly defined "
                                                      "table can't be an array")
                        elif arrayoftables:
                            currentlevel[group].append(_dict())
                        else:
                            raise TomlDecodeError("What? " + group +
                                                  " already exists?" +
                                                  str(currentlevel))
                except TypeError:
                    currentlevel = currentlevel[-1]
                    try:
                        currentlevel[group]
                    except KeyError:
                        currentlevel[group] = _dict()
                        if i == len(groups) - 1 and arrayoftables:
                            currentlevel[group] = [_dict()]
                except KeyError:
                    if i != len(groups) - 1:
                        implicitgroups.append(group)
                    currentlevel[group] = _dict()
                    if i == len(groups) - 1 and arrayoftables:
                        currentlevel[group] = [_dict()]
                currentlevel = currentlevel[group]
                if arrayoftables:
                    try:
                        currentlevel = currentlevel[-1]
                    except KeyError:
                        pass
        elif line[0] == "{":
            if line[-1] != "}":
                raise TomlDecodeError("Line breaks are not allowed in inline"
                                      "objects")
            try:
                _load_inline_object(line, currentlevel, _dict, multikey,
                                    multibackslash)
            except ValueError as err:
                raise TomlDecodeError(str(err))
        elif "=" in line:
            try:
                ret = _load_line(line, currentlevel, _dict, multikey,
                                 multibackslash)
            except ValueError as err:
                raise TomlDecodeError(str(err))
            if ret is not None:
                multikey, multilinestr, multibackslash = ret
    return retval


def _load_inline_object(line, currentlevel, _dict, multikey=False,
                        multibackslash=False):
    candidate_groups = line[1:-1].split(",")
    groups = []
    if len(candidate_groups) == 1 and not candidate_groups[0].strip():
        candidate_groups.pop()
    while len(candidate_groups) > 0:
        candidate_group = candidate_groups.pop(0)
        try:
            _, value = candidate_group.split('=', 1)
        except ValueError:
            raise ValueError("Invalid inline table encountered")
        value = value.strip()
        if ((value[0] == value[-1] and value[0] in ('"', "'")) or (
                value[0] in '-0123456789' or
                value in ('true', 'false') or
                (value[0] == "[" and value[-1] == "]") or
                (value[0] == '{' and value[-1] == '}'))):
            groups.append(candidate_group)
        elif len(candidate_groups) > 0:
            candidate_groups[0] = candidate_group + "," + candidate_groups[0]
        else:
            raise ValueError("Invalid inline table value encountered")
    for group in groups:
        status = _load_line(group, currentlevel, _dict, multikey,
                            multibackslash)
        if status is not None:
            break


# Matches a TOML number, which allows underscores for readability
_number_with_underscores = re.compile('([0-9])(_([0-9]))*')


def _strictly_valid_num(n):
    n = n.strip()
    if not n:
        return False
    if n[0] == '_':
        return False
    if n[-1] == '_':
        return False
    if "_." in n or "._" in n:
        return False
    if len(n) == 1:
        return True
    if n[0] == '0' and n[1] != '.':
        return False
    if n[0] == '+' or n[0] == '-':
        n = n[1:]
        if n[0] == '0' and n[1] != '.':
            return False
    if '__' in n:
        return False
    return True


def _get_split_on_quotes(line):
    doublequotesplits = line.split('"')
    quoted = False
    quotesplits = []
    if len(doublequotesplits) > 1 and "'" in doublequotesplits[0]:
        singlequotesplits = doublequotesplits[0].split("'")
        doublequotesplits = doublequotesplits[1:]
        while len(singlequotesplits) % 2 == 0 and len(doublequotesplits):
            singlequotesplits[-1] += '"' + doublequotesplits[0]
            doublequotesplits = doublequotesplits[1:]
            if "'" in singlequotesplits[-1]:
                singlequotesplits = (singlequotesplits[:-1] +
                                     singlequotesplits[-1].split("'"))
        quotesplits += singlequotesplits
    for doublequotesplit in doublequotesplits:
        if quoted:
            quotesplits.append(doublequotesplit)
        else:
            quotesplits += doublequotesplit.split("'")
            quoted = not quoted
    return quotesplits


def _load_line(line, currentlevel, _dict, multikey, multibackslash):
    i = 1
    quotesplits = _get_split_on_quotes(line)
    quoted = False
    for quotesplit in quotesplits:
        if not quoted and '=' in quotesplit:
            break
        i += quotesplit.count('=')
        quoted = not quoted
    pair = line.split('=', i)
    strictly_valid = _strictly_valid_num(pair[-1])
    if _number_with_underscores.match(pair[-1]):
        pair[-1] = pair[-1].replace('_', '')
    while len(pair[-1]) and (pair[-1][0] != ' ' and pair[-1][0] != '\t' and
                             pair[-1][0] != "'" and pair[-1][0] != '"' and
                             pair[-1][0] != '[' and pair[-1][0] != '{' and
                             pair[-1] != 'true' and pair[-1] != 'false'):
        try:
            float(pair[-1])
            break
        except ValueError:
            pass
        if _load_date(pair[-1]) is not None:
            break
        i += 1
        prev_val = pair[-1]
        pair = line.split('=', i)
        if prev_val == pair[-1]:
            raise ValueError("Invalid date or number")
        if strictly_valid:
            strictly_valid = _strictly_valid_num(pair[-1])
    pair = ['='.join(pair[:-1]).strip(), pair[-1].strip()]
    if (pair[0][0] == '"' or pair[0][0] == "'") and \
            (pair[0][-1] == '"' or pair[0][-1] == "'"):
        pair[0] = pair[0][1:-1]
    if len(pair[1]) > 2 and ((pair[1][0] == '"' or pair[1][0] == "'") and
                             pair[1][1] == pair[1][0] and
                             pair[1][2] == pair[1][0] and
                             not (len(pair[1]) > 5 and
                                  pair[1][-1] == pair[1][0] and
                                  pair[1][-2] == pair[1][0] and
                                  pair[1][-3] == pair[1][0])):
        k = len(pair[1]) - 1
        while k > -1 and pair[1][k] == '\\':
            multibackslash = not multibackslash
            k -= 1
        if multibackslash:
            multilinestr = pair[1][:-1]
        else:
            multilinestr = pair[1] + "\n"
        multikey = pair[0]
    else:
        value, vtype = _load_value(pair[1], _dict, strictly_valid)
    try:
        currentlevel[pair[0]]
        raise ValueError("Duplicate keys!")
    except KeyError:
        if multikey:
            return multikey, multilinestr, multibackslash
        else:
            currentlevel[pair[0]] = value


def _load_date(val):
    microsecond = 0
    tz = None
    try:
        if len(val) > 19:
            if val[19] == '.':
                if val[-1].upper() == 'Z':
                    subsecondval = val[20:-1]
                    tzval = "Z"
                else:
                    subsecondvalandtz = val[20:]
                    if '+' in subsecondvalandtz:
                        splitpoint = subsecondvalandtz.index('+')
                        subsecondval = subsecondvalandtz[:splitpoint]
                        tzval = subsecondvalandtz[splitpoint:]
                    elif '-' in subsecondvalandtz:
                        splitpoint = subsecondvalandtz.index('-')
                        subsecondval = subsecondvalandtz[:splitpoint]
                        tzval = subsecondvalandtz[splitpoint:]
                tz = TomlTz(tzval)
                microsecond = int(int(subsecondval) *
                                  (10 ** (6 - len(subsecondval))))
            else:
                tz = TomlTz(val[19:])
    except ValueError:
        tz = None
    if "-" not in val[1:]:
        return None
    try:
        d = datetime.datetime(
            int(val[:4]), int(val[5:7]),
            int(val[8:10]), int(val[11:13]),
            int(val[14:16]), int(val[17:19]), microsecond, tz)
    except ValueError:
        return None
    return d


def _load_unicode_escapes(v, hexbytes, prefix):
    skip = False
    i = len(v) - 1
    while i > -1 and v[i] == '\\':
        skip = not skip
        i -= 1
    for hx in hexbytes:
        if skip:
            skip = False
            i = len(hx) - 1
            while i > -1 and hx[i] == '\\':
                skip = not skip
                i -= 1
            v += prefix
            v += hx
            continue
        hxb = ""
        i = 0
        hxblen = 4
        if prefix == "\\U":
            hxblen = 8
        hxb = ''.join(hx[i:i + hxblen]).lower()
        if hxb.strip('0123456789abcdef'):
            raise ValueError("Invalid escape sequence: " + hxb)
        if hxb[0] == "d" and hxb[1].strip('01234567'):
            raise ValueError("Invalid escape sequence: " + hxb +
                             ". Only scalar unicode points are allowed.")
        v += unichr(int(hxb, 16))
        v += unicode(hx[len(hxb):])
    return v


# Unescape TOML string values.

# content after the \
_escapes = ['0', 'b', 'f', 'n', 'r', 't', '"']
# What it should be replaced by
_escapedchars = ['\0', '\b', '\f', '\n', '\r', '\t', '\"']
# Used for substitution
_escape_to_escapedchars = dict(zip(_escapes, _escapedchars))


def _unescape(v):
    """Unescape characters in a TOML string."""
    i = 0
    backslash = False
    while i < len(v):
        if backslash:
            backslash = False
            if v[i] in _escapes:
                v = v[:i - 1] + _escape_to_escapedchars[v[i]] + v[i + 1:]
            elif v[i] == '\\':
                v = v[:i - 1] + v[i:]
            elif v[i] == 'u' or v[i] == 'U':
                i += 1
            else:
                raise ValueError("Reserved escape sequence used")
            continue
        elif v[i] == '\\':
            backslash = True
        i += 1
    return v


def _load_value(v, _dict, strictly_valid=True):
    if not v:
        raise ValueError("Empty value is invalid")
    if v == 'true':
        return (True, "bool")
    elif v == 'false':
        return (False, "bool")
    elif v[0] == '"':
        testv = v[1:].split('"')
        triplequote = False
        triplequotecount = 0
        if len(testv) > 1 and testv[0] == '' and testv[1] == '':
            testv = testv[2:]
            triplequote = True
        closed = False
        for tv in testv:
            if tv == '':
                if triplequote:
                    triplequotecount += 1
                else:
                    closed = True
            else:
                oddbackslash = False
                try:
                    i = -1
                    j = tv[i]
                    while j == '\\':
                        oddbackslash = not oddbackslash
                        i -= 1
                        j = tv[i]
                except IndexError:
                    pass
                if not oddbackslash:
                    if closed:
                        raise ValueError("Stuff after closed string. WTF?")
                    else:
                        if not triplequote or triplequotecount > 1:
                            closed = True
                        else:
                            triplequotecount = 0
        escapeseqs = v.split('\\')[1:]
        backslash = False
        for i in escapeseqs:
            if i == '':
                backslash = not backslash
            else:
                if i[0] not in _escapes and (i[0] != 'u' and i[0] != 'U' and
                                             not backslash):
                    raise ValueError("Reserved escape sequence used")
                if backslash:
                    backslash = False
        for prefix in ["\\u", "\\U"]:
            if prefix in v:
                hexbytes = v.split(prefix)
                v = _load_unicode_escapes(hexbytes[0], hexbytes[1:], prefix)
        v = _unescape(v)
        if len(v) > 1 and v[1] == '"' and (len(v) < 3 or v[1] == v[2]):
            v = v[2:-2]
        return (v[1:-1], "str")
    elif v[0] == "'":
        if v[1] == "'" and (len(v) < 3 or v[1] == v[2]):
            v = v[2:-2]
        return (v[1:-1], "str")
    elif v[0] == '[':
        return (_load_array(v, _dict), "array")
    elif v[0] == '{':
        inline_object = _get_empty_inline_table(_dict)
        _load_inline_object(v, inline_object, _dict)
        return (inline_object, "inline_object")
    else:
        parsed_date = _load_date(v)
        if parsed_date is not None:
            return (parsed_date, "date")
        if not strictly_valid:
            raise ValueError("Weirdness with leading zeroes or "
                             "underscores in your number.")
        itype = "int"
        neg = False
        if v[0] == '-':
            neg = True
            v = v[1:]
        elif v[0] == '+':
            v = v[1:]
        v = v.replace('_', '')
        if '.' in v or 'e' in v or 'E' in v:
            if '.' in v and v.split('.', 1)[1] == '':
                raise ValueError("This float is missing digits after "
                                 "the point")
            if v[0] not in '0123456789':
                raise ValueError("This float doesn't have a leading digit")
            v = float(v)
            itype = "float"
        else:
            v = int(v)
        if neg:
            return (0 - v, itype)
        return (v, itype)


def _bounded_string(s):
    if len(s) == 0:
        return True
    if s[-1] != s[0]:
        return False
    i = -2
    backslash = False
    while len(s) + i > 0:
        if s[i] == "\\":
            backslash = not backslash
            i -= 1
        else:
            break
    return not backslash


def _load_array(a, _dict):
    atype = None
    retval = []
    a = a.strip()
    if '[' not in a[1:-1] or "" != a[1:-1].split('[')[0].strip():
        strarray = False
        tmpa = a[1:-1].strip()
        if tmpa != '' and (tmpa[0] == '"' or tmpa[0] == "'"):
            strarray = True
        if not a[1:-1].strip().startswith('{'):
            a = a[1:-1].split(',')
        else:
            # a is an inline object, we must find the matching parenthesis
            # to define groups
            new_a = []
            start_group_index = 1
            end_group_index = 2
            in_str = False
            while end_group_index < len(a[1:]):
                if a[end_group_index] == '"' or a[end_group_index] == "'":
                    if in_str:
                        backslash_index = end_group_index - 1
                        while (backslash_index > -1 and
                               a[backslash_index] == '\\'):
                            in_str = not in_str
                            backslash_index -= 1
                    in_str = not in_str
                if in_str or a[end_group_index] != '}':
                    end_group_index += 1
                    continue

                # Increase end_group_index by 1 to get the closing bracket
                end_group_index += 1
                new_a.append(a[start_group_index:end_group_index])

                # The next start index is at least after the closing bracket, a
                # closing bracket can be followed by a comma since we are in
                # an array.
                start_group_index = end_group_index + 1
                while (start_group_index < len(a[1:]) and
                       a[start_group_index] != '{'):
                    start_group_index += 1
                end_group_index = start_group_index + 1
            a = new_a
        b = 0
        if strarray:
            while b < len(a) - 1:
                ab = a[b].strip()
                while (not _bounded_string(ab) or
                       (len(ab) > 2 and
                        ab[0] == ab[1] == ab[2] and
                        ab[-2] != ab[0] and
                        ab[-3] != ab[0])):
                    a[b] = a[b] + ',' + a[b + 1]
                    ab = a[b].strip()
                    if b < len(a) - 2:
                        a = a[:b + 1] + a[b + 2:]
                    else:
                        a = a[:b + 1]
                b += 1
    else:
        al = list(a[1:-1])
        a = []
        openarr = 0
        j = 0
        for i in _range(len(al)):
            if al[i] == '[':
                openarr += 1
            elif al[i] == ']':
                openarr -= 1
            elif al[i] == ',' and not openarr:
                a.append(''.join(al[j:i]))
                j = i + 1
        a.append(''.join(al[j:]))
    for i in _range(len(a)):
        a[i] = a[i].strip()
        if a[i] != '':
            nval, ntype = _load_value(a[i], _dict)
            if atype:
                if ntype != atype:
                    raise ValueError("Not a homogeneous array")
            else:
                atype = ntype
            retval.append(nval)
    return retval


def dump(o, f):
    """Writes out dict as toml to a file

    Args:
        o: Object to dump into toml
        f: File descriptor where the toml should be stored

    Returns:
        String containing the toml corresponding to dictionary

    Raises:
        TypeError: When anything other than file descriptor is passed
    """

    if not f.write:
        raise TypeError("You can only dump an object to a file descriptor")
    d = dumps(o)
    f.write(d)
    return d


def dumps(o, preserve=False):
    """Stringifies input dict as toml

    Args:
        o: Object to dump into toml

        preserve: Boolean parameter. If true, preserve inline tables.

    Returns:
        String containing the toml corresponding to dict
    """

    retval = ""
    addtoretval, sections = _dump_sections(o, "")
    retval += addtoretval
    while sections != {}:
        newsections = {}
        for section in sections:
            addtoretval, addtosections = _dump_sections(sections[section],
                                                        section, preserve)
            if addtoretval or (not addtoretval and not addtosections):
                if retval and retval[-2:] != "\n\n":
                    retval += "\n"
                retval += "[" + section + "]\n"
                if addtoretval:
                    retval += addtoretval
            for s in addtosections:
                newsections[section + "." + s] = addtosections[s]
        sections = newsections
    return retval


def _dump_sections(o, sup, preserve=False):
    retstr = ""
    if sup != "" and sup[-1] != ".":
        sup += '.'
    retdict = o.__class__()
    arraystr = ""
    for section in o:
        section = unicode(section)
        qsection = section
        if not re.match(r'^[A-Za-z0-9_-]+$', section):
            if '"' in section:
                qsection = "'" + section + "'"
            else:
                qsection = '"' + section + '"'
        if not isinstance(o[section], dict):
            arrayoftables = False
            if isinstance(o[section], list):
                for a in o[section]:
                    if isinstance(a, dict):
                        arrayoftables = True
            if arrayoftables:
                for a in o[section]:
                    arraytabstr = "\n"
                    arraystr += "[[" + sup + qsection + "]]\n"
                    s, d = _dump_sections(a, sup + qsection)
                    if s:
                        if s[0] == "[":
                            arraytabstr += s
                        else:
                            arraystr += s
                    while d != {}:
                        newd = {}
                        for dsec in d:
                            s1, d1 = _dump_sections(d[dsec], sup + qsection +
                                                    "." + dsec)
                            if s1:
                                arraytabstr += ("[" + sup + qsection + "." +
                                                dsec + "]\n")
                                arraytabstr += s1
                            for s1 in d1:
                                newd[dsec + "." + s1] = d1[s1]
                        d = newd
                    arraystr += arraytabstr
            else:
                if o[section] is not None:
                    retstr += (qsection + " = " +
                               unicode(_dump_value(o[section])) + '\n')
        elif preserve and isinstance(o[section], InlineTableDict):
            retstr += (qsection + " = " + _dump_inline_table(o[section]))
        else:
            retdict[qsection] = o[section]
    retstr += arraystr
    return (retstr, retdict)


def _dump_inline_table(section):
    """Preserve inline table in its compact syntax instead of expanding
    into subsection.

    https://github.com/toml-lang/toml#user-content-inline-table
    """
    retval = ""
    if isinstance(section, dict):
        val_list = []
        for k, v in section.items():
            val = _dump_inline_table(v)
            val_list.append(k + " = " + val)
        retval += "{ " + ", ".join(val_list) + " }\n"
        return retval
    else:
        return unicode(_dump_value(section))


def _dump_value(v):
    dump_funcs = {
        str: _dump_str,
        unicode: _dump_str,
        list: _dump_list,
        int: lambda v: v,
        bool: lambda v: unicode(v).lower(),
        float: _dump_float,
        datetime.datetime: lambda v: v.isoformat().replace('+00:00', 'Z'),
    }
    # Lookup function corresponding to v's type
    dump_fn = dump_funcs.get(type(v))
    if dump_fn is None and hasattr(v, '__iter__'):
        dump_fn = dump_funcs[list]
    # Evaluate function (if it exists) else return v
    return dump_fn(v) if dump_fn is not None else dump_funcs[str](v)


def _dump_str(v):
    if sys.version_info < (3,) and hasattr(v, 'decode') and isinstance(v, str):
        v = v.decode('utf-8')
    v = "%r" % v
    if v[0] == 'u':
        v = v[1:]
    singlequote = v.startswith("'")
    if singlequote or v.startswith('"'):
        v = v[1:-1]
    if singlequote:
        v = v.replace("\\'", "'")
        v = v.replace('"', '\\"')
    v = v.split("\\x")
    while len(v) > 1:
        i = -1
        if not v[0]:
            v = v[1:]
        v[0] = v[0].replace("\\\\", "\\")
        # No, I don't know why != works and == breaks
        joinx = v[0][i] != "\\"
        while v[0][:i] and v[0][i] == "\\":
            joinx = not joinx
            i -= 1
        if joinx:
            joiner = "x"
        else:
            joiner = "u00"
        v = [v[0] + joiner + v[1]] + v[2:]
    return unicode('"' + v[0] + '"')


def _dump_list(v):
    retval = "["
    for u in v:
        retval += " " + unicode(_dump_value(u)) + ","
    retval += "]"
    return retval


def _dump_float(v):
    return "{0:.16}".format(v).replace("e+0", "e+").replace("e-0", "e-")