(root)/
Python-3.12.0/
Lib/
tomllib/
_parser.py
       1  # SPDX-License-Identifier: MIT
       2  # SPDX-FileCopyrightText: 2021 Taneli Hukkinen
       3  # Licensed to PSF under a Contributor Agreement.
       4  
       5  from __future__ import annotations
       6  
       7  from collections.abc import Iterable
       8  import string
       9  from types import MappingProxyType
      10  from typing import Any, BinaryIO, NamedTuple
      11  
      12  from ._re import (
      13      RE_DATETIME,
      14      RE_LOCALTIME,
      15      RE_NUMBER,
      16      match_to_datetime,
      17      match_to_localtime,
      18      match_to_number,
      19  )
      20  from ._types import Key, ParseFloat, Pos
      21  
      22  ASCII_CTRL = frozenset(chr(i) for i in range(32)) | frozenset(chr(127))
      23  
      24  # Neither of these sets include quotation mark or backslash. They are
      25  # currently handled as separate cases in the parser functions.
      26  ILLEGAL_BASIC_STR_CHARS = ASCII_CTRL - frozenset("\t")
      27  ILLEGAL_MULTILINE_BASIC_STR_CHARS = ASCII_CTRL - frozenset("\t\n")
      28  
      29  ILLEGAL_LITERAL_STR_CHARS = ILLEGAL_BASIC_STR_CHARS
      30  ILLEGAL_MULTILINE_LITERAL_STR_CHARS = ILLEGAL_MULTILINE_BASIC_STR_CHARS
      31  
      32  ILLEGAL_COMMENT_CHARS = ILLEGAL_BASIC_STR_CHARS
      33  
      34  TOML_WS = frozenset(" \t")
      35  TOML_WS_AND_NEWLINE = TOML_WS | frozenset("\n")
      36  BARE_KEY_CHARS = frozenset(string.ascii_letters + string.digits + "-_")
      37  KEY_INITIAL_CHARS = BARE_KEY_CHARS | frozenset("\"'")
      38  HEXDIGIT_CHARS = frozenset(string.hexdigits)
      39  
      40  BASIC_STR_ESCAPE_REPLACEMENTS = MappingProxyType(
      41      {
      42          "\\b": "\u0008",  # backspace
      43          "\\t": "\u0009",  # tab
      44          "\\n": "\u000A",  # linefeed
      45          "\\f": "\u000C",  # form feed
      46          "\\r": "\u000D",  # carriage return
      47          '\\"': "\u0022",  # quote
      48          "\\\\": "\u005C",  # backslash
      49      }
      50  )
      51  
      52  
      53  class ESC[4;38;5;81mTOMLDecodeError(ESC[4;38;5;149mValueError):
      54      """An error raised if a document is not valid TOML."""
      55  
      56  
      57  def load(fp: BinaryIO, /, *, parse_float: ParseFloat = float) -> dict[str, Any]:
      58      """Parse TOML from a binary file object."""
      59      b = fp.read()
      60      try:
      61          s = b.decode()
      62      except AttributeError:
      63          raise TypeError(
      64              "File must be opened in binary mode, e.g. use `open('foo.toml', 'rb')`"
      65          ) from None
      66      return loads(s, parse_float=parse_float)
      67  
      68  
      69  def loads(s: str, /, *, parse_float: ParseFloat = float) -> dict[str, Any]:  # noqa: C901
      70      """Parse TOML from a string."""
      71  
      72      # The spec allows converting "\r\n" to "\n", even in string
      73      # literals. Let's do so to simplify parsing.
      74      src = s.replace("\r\n", "\n")
      75      pos = 0
      76      out = Output(NestedDict(), Flags())
      77      header: Key = ()
      78      parse_float = make_safe_parse_float(parse_float)
      79  
      80      # Parse one statement at a time
      81      # (typically means one line in TOML source)
      82      while True:
      83          # 1. Skip line leading whitespace
      84          pos = skip_chars(src, pos, TOML_WS)
      85  
      86          # 2. Parse rules. Expect one of the following:
      87          #    - end of file
      88          #    - end of line
      89          #    - comment
      90          #    - key/value pair
      91          #    - append dict to list (and move to its namespace)
      92          #    - create dict (and move to its namespace)
      93          # Skip trailing whitespace when applicable.
      94          try:
      95              char = src[pos]
      96          except IndexError:
      97              break
      98          if char == "\n":
      99              pos += 1
     100              continue
     101          if char in KEY_INITIAL_CHARS:
     102              pos = key_value_rule(src, pos, out, header, parse_float)
     103              pos = skip_chars(src, pos, TOML_WS)
     104          elif char == "[":
     105              try:
     106                  second_char: str | None = src[pos + 1]
     107              except IndexError:
     108                  second_char = None
     109              out.flags.finalize_pending()
     110              if second_char == "[":
     111                  pos, header = create_list_rule(src, pos, out)
     112              else:
     113                  pos, header = create_dict_rule(src, pos, out)
     114              pos = skip_chars(src, pos, TOML_WS)
     115          elif char != "#":
     116              raise suffixed_err(src, pos, "Invalid statement")
     117  
     118          # 3. Skip comment
     119          pos = skip_comment(src, pos)
     120  
     121          # 4. Expect end of line or end of file
     122          try:
     123              char = src[pos]
     124          except IndexError:
     125              break
     126          if char != "\n":
     127              raise suffixed_err(
     128                  src, pos, "Expected newline or end of document after a statement"
     129              )
     130          pos += 1
     131  
     132      return out.data.dict
     133  
     134  
     135  class ESC[4;38;5;81mFlags:
     136      """Flags that map to parsed keys/namespaces."""
     137  
     138      # Marks an immutable namespace (inline array or inline table).
     139      FROZEN = 0
     140      # Marks a nest that has been explicitly created and can no longer
     141      # be opened using the "[table]" syntax.
     142      EXPLICIT_NEST = 1
     143  
     144      def __init__(self) -> None:
     145          self._flags: dict[str, dict] = {}
     146          self._pending_flags: set[tuple[Key, int]] = set()
     147  
     148      def add_pending(self, key: Key, flag: int) -> None:
     149          self._pending_flags.add((key, flag))
     150  
     151      def finalize_pending(self) -> None:
     152          for key, flag in self._pending_flags:
     153              self.set(key, flag, recursive=False)
     154          self._pending_flags.clear()
     155  
     156      def unset_all(self, key: Key) -> None:
     157          cont = self._flags
     158          for k in key[:-1]:
     159              if k not in cont:
     160                  return
     161              cont = cont[k]["nested"]
     162          cont.pop(key[-1], None)
     163  
     164      def set(self, key: Key, flag: int, *, recursive: bool) -> None:  # noqa: A003
     165          cont = self._flags
     166          key_parent, key_stem = key[:-1], key[-1]
     167          for k in key_parent:
     168              if k not in cont:
     169                  cont[k] = {"flags": set(), "recursive_flags": set(), "nested": {}}
     170              cont = cont[k]["nested"]
     171          if key_stem not in cont:
     172              cont[key_stem] = {"flags": set(), "recursive_flags": set(), "nested": {}}
     173          cont[key_stem]["recursive_flags" if recursive else "flags"].add(flag)
     174  
     175      def is_(self, key: Key, flag: int) -> bool:
     176          if not key:
     177              return False  # document root has no flags
     178          cont = self._flags
     179          for k in key[:-1]:
     180              if k not in cont:
     181                  return False
     182              inner_cont = cont[k]
     183              if flag in inner_cont["recursive_flags"]:
     184                  return True
     185              cont = inner_cont["nested"]
     186          key_stem = key[-1]
     187          if key_stem in cont:
     188              cont = cont[key_stem]
     189              return flag in cont["flags"] or flag in cont["recursive_flags"]
     190          return False
     191  
     192  
     193  class ESC[4;38;5;81mNestedDict:
     194      def __init__(self) -> None:
     195          # The parsed content of the TOML document
     196          self.dict: dict[str, Any] = {}
     197  
     198      def get_or_create_nest(
     199          self,
     200          key: Key,
     201          *,
     202          access_lists: bool = True,
     203      ) -> dict:
     204          cont: Any = self.dict
     205          for k in key:
     206              if k not in cont:
     207                  cont[k] = {}
     208              cont = cont[k]
     209              if access_lists and isinstance(cont, list):
     210                  cont = cont[-1]
     211              if not isinstance(cont, dict):
     212                  raise KeyError("There is no nest behind this key")
     213          return cont
     214  
     215      def append_nest_to_list(self, key: Key) -> None:
     216          cont = self.get_or_create_nest(key[:-1])
     217          last_key = key[-1]
     218          if last_key in cont:
     219              list_ = cont[last_key]
     220              if not isinstance(list_, list):
     221                  raise KeyError("An object other than list found behind this key")
     222              list_.append({})
     223          else:
     224              cont[last_key] = [{}]
     225  
     226  
     227  class ESC[4;38;5;81mOutput(ESC[4;38;5;149mNamedTuple):
     228      data: NestedDict
     229      flags: Flags
     230  
     231  
     232  def skip_chars(src: str, pos: Pos, chars: Iterable[str]) -> Pos:
     233      try:
     234          while src[pos] in chars:
     235              pos += 1
     236      except IndexError:
     237          pass
     238      return pos
     239  
     240  
     241  def skip_until(
     242      src: str,
     243      pos: Pos,
     244      expect: str,
     245      *,
     246      error_on: frozenset[str],
     247      error_on_eof: bool,
     248  ) -> Pos:
     249      try:
     250          new_pos = src.index(expect, pos)
     251      except ValueError:
     252          new_pos = len(src)
     253          if error_on_eof:
     254              raise suffixed_err(src, new_pos, f"Expected {expect!r}") from None
     255  
     256      if not error_on.isdisjoint(src[pos:new_pos]):
     257          while src[pos] not in error_on:
     258              pos += 1
     259          raise suffixed_err(src, pos, f"Found invalid character {src[pos]!r}")
     260      return new_pos
     261  
     262  
     263  def skip_comment(src: str, pos: Pos) -> Pos:
     264      try:
     265          char: str | None = src[pos]
     266      except IndexError:
     267          char = None
     268      if char == "#":
     269          return skip_until(
     270              src, pos + 1, "\n", error_on=ILLEGAL_COMMENT_CHARS, error_on_eof=False
     271          )
     272      return pos
     273  
     274  
     275  def skip_comments_and_array_ws(src: str, pos: Pos) -> Pos:
     276      while True:
     277          pos_before_skip = pos
     278          pos = skip_chars(src, pos, TOML_WS_AND_NEWLINE)
     279          pos = skip_comment(src, pos)
     280          if pos == pos_before_skip:
     281              return pos
     282  
     283  
     284  def create_dict_rule(src: str, pos: Pos, out: Output) -> tuple[Pos, Key]:
     285      pos += 1  # Skip "["
     286      pos = skip_chars(src, pos, TOML_WS)
     287      pos, key = parse_key(src, pos)
     288  
     289      if out.flags.is_(key, Flags.EXPLICIT_NEST) or out.flags.is_(key, Flags.FROZEN):
     290          raise suffixed_err(src, pos, f"Cannot declare {key} twice")
     291      out.flags.set(key, Flags.EXPLICIT_NEST, recursive=False)
     292      try:
     293          out.data.get_or_create_nest(key)
     294      except KeyError:
     295          raise suffixed_err(src, pos, "Cannot overwrite a value") from None
     296  
     297      if not src.startswith("]", pos):
     298          raise suffixed_err(src, pos, "Expected ']' at the end of a table declaration")
     299      return pos + 1, key
     300  
     301  
     302  def create_list_rule(src: str, pos: Pos, out: Output) -> tuple[Pos, Key]:
     303      pos += 2  # Skip "[["
     304      pos = skip_chars(src, pos, TOML_WS)
     305      pos, key = parse_key(src, pos)
     306  
     307      if out.flags.is_(key, Flags.FROZEN):
     308          raise suffixed_err(src, pos, f"Cannot mutate immutable namespace {key}")
     309      # Free the namespace now that it points to another empty list item...
     310      out.flags.unset_all(key)
     311      # ...but this key precisely is still prohibited from table declaration
     312      out.flags.set(key, Flags.EXPLICIT_NEST, recursive=False)
     313      try:
     314          out.data.append_nest_to_list(key)
     315      except KeyError:
     316          raise suffixed_err(src, pos, "Cannot overwrite a value") from None
     317  
     318      if not src.startswith("]]", pos):
     319          raise suffixed_err(src, pos, "Expected ']]' at the end of an array declaration")
     320      return pos + 2, key
     321  
     322  
     323  def key_value_rule(
     324      src: str, pos: Pos, out: Output, header: Key, parse_float: ParseFloat
     325  ) -> Pos:
     326      pos, key, value = parse_key_value_pair(src, pos, parse_float)
     327      key_parent, key_stem = key[:-1], key[-1]
     328      abs_key_parent = header + key_parent
     329  
     330      relative_path_cont_keys = (header + key[:i] for i in range(1, len(key)))
     331      for cont_key in relative_path_cont_keys:
     332          # Check that dotted key syntax does not redefine an existing table
     333          if out.flags.is_(cont_key, Flags.EXPLICIT_NEST):
     334              raise suffixed_err(src, pos, f"Cannot redefine namespace {cont_key}")
     335          # Containers in the relative path can't be opened with the table syntax or
     336          # dotted key/value syntax in following table sections.
     337          out.flags.add_pending(cont_key, Flags.EXPLICIT_NEST)
     338  
     339      if out.flags.is_(abs_key_parent, Flags.FROZEN):
     340          raise suffixed_err(
     341              src, pos, f"Cannot mutate immutable namespace {abs_key_parent}"
     342          )
     343  
     344      try:
     345          nest = out.data.get_or_create_nest(abs_key_parent)
     346      except KeyError:
     347          raise suffixed_err(src, pos, "Cannot overwrite a value") from None
     348      if key_stem in nest:
     349          raise suffixed_err(src, pos, "Cannot overwrite a value")
     350      # Mark inline table and array namespaces recursively immutable
     351      if isinstance(value, (dict, list)):
     352          out.flags.set(header + key, Flags.FROZEN, recursive=True)
     353      nest[key_stem] = value
     354      return pos
     355  
     356  
     357  def parse_key_value_pair(
     358      src: str, pos: Pos, parse_float: ParseFloat
     359  ) -> tuple[Pos, Key, Any]:
     360      pos, key = parse_key(src, pos)
     361      try:
     362          char: str | None = src[pos]
     363      except IndexError:
     364          char = None
     365      if char != "=":
     366          raise suffixed_err(src, pos, "Expected '=' after a key in a key/value pair")
     367      pos += 1
     368      pos = skip_chars(src, pos, TOML_WS)
     369      pos, value = parse_value(src, pos, parse_float)
     370      return pos, key, value
     371  
     372  
     373  def parse_key(src: str, pos: Pos) -> tuple[Pos, Key]:
     374      pos, key_part = parse_key_part(src, pos)
     375      key: Key = (key_part,)
     376      pos = skip_chars(src, pos, TOML_WS)
     377      while True:
     378          try:
     379              char: str | None = src[pos]
     380          except IndexError:
     381              char = None
     382          if char != ".":
     383              return pos, key
     384          pos += 1
     385          pos = skip_chars(src, pos, TOML_WS)
     386          pos, key_part = parse_key_part(src, pos)
     387          key += (key_part,)
     388          pos = skip_chars(src, pos, TOML_WS)
     389  
     390  
     391  def parse_key_part(src: str, pos: Pos) -> tuple[Pos, str]:
     392      try:
     393          char: str | None = src[pos]
     394      except IndexError:
     395          char = None
     396      if char in BARE_KEY_CHARS:
     397          start_pos = pos
     398          pos = skip_chars(src, pos, BARE_KEY_CHARS)
     399          return pos, src[start_pos:pos]
     400      if char == "'":
     401          return parse_literal_str(src, pos)
     402      if char == '"':
     403          return parse_one_line_basic_str(src, pos)
     404      raise suffixed_err(src, pos, "Invalid initial character for a key part")
     405  
     406  
     407  def parse_one_line_basic_str(src: str, pos: Pos) -> tuple[Pos, str]:
     408      pos += 1
     409      return parse_basic_str(src, pos, multiline=False)
     410  
     411  
     412  def parse_array(src: str, pos: Pos, parse_float: ParseFloat) -> tuple[Pos, list]:
     413      pos += 1
     414      array: list = []
     415  
     416      pos = skip_comments_and_array_ws(src, pos)
     417      if src.startswith("]", pos):
     418          return pos + 1, array
     419      while True:
     420          pos, val = parse_value(src, pos, parse_float)
     421          array.append(val)
     422          pos = skip_comments_and_array_ws(src, pos)
     423  
     424          c = src[pos : pos + 1]
     425          if c == "]":
     426              return pos + 1, array
     427          if c != ",":
     428              raise suffixed_err(src, pos, "Unclosed array")
     429          pos += 1
     430  
     431          pos = skip_comments_and_array_ws(src, pos)
     432          if src.startswith("]", pos):
     433              return pos + 1, array
     434  
     435  
     436  def parse_inline_table(src: str, pos: Pos, parse_float: ParseFloat) -> tuple[Pos, dict]:
     437      pos += 1
     438      nested_dict = NestedDict()
     439      flags = Flags()
     440  
     441      pos = skip_chars(src, pos, TOML_WS)
     442      if src.startswith("}", pos):
     443          return pos + 1, nested_dict.dict
     444      while True:
     445          pos, key, value = parse_key_value_pair(src, pos, parse_float)
     446          key_parent, key_stem = key[:-1], key[-1]
     447          if flags.is_(key, Flags.FROZEN):
     448              raise suffixed_err(src, pos, f"Cannot mutate immutable namespace {key}")
     449          try:
     450              nest = nested_dict.get_or_create_nest(key_parent, access_lists=False)
     451          except KeyError:
     452              raise suffixed_err(src, pos, "Cannot overwrite a value") from None
     453          if key_stem in nest:
     454              raise suffixed_err(src, pos, f"Duplicate inline table key {key_stem!r}")
     455          nest[key_stem] = value
     456          pos = skip_chars(src, pos, TOML_WS)
     457          c = src[pos : pos + 1]
     458          if c == "}":
     459              return pos + 1, nested_dict.dict
     460          if c != ",":
     461              raise suffixed_err(src, pos, "Unclosed inline table")
     462          if isinstance(value, (dict, list)):
     463              flags.set(key, Flags.FROZEN, recursive=True)
     464          pos += 1
     465          pos = skip_chars(src, pos, TOML_WS)
     466  
     467  
     468  def parse_basic_str_escape(
     469      src: str, pos: Pos, *, multiline: bool = False
     470  ) -> tuple[Pos, str]:
     471      escape_id = src[pos : pos + 2]
     472      pos += 2
     473      if multiline and escape_id in {"\\ ", "\\\t", "\\\n"}:
     474          # Skip whitespace until next non-whitespace character or end of
     475          # the doc. Error if non-whitespace is found before newline.
     476          if escape_id != "\\\n":
     477              pos = skip_chars(src, pos, TOML_WS)
     478              try:
     479                  char = src[pos]
     480              except IndexError:
     481                  return pos, ""
     482              if char != "\n":
     483                  raise suffixed_err(src, pos, "Unescaped '\\' in a string")
     484              pos += 1
     485          pos = skip_chars(src, pos, TOML_WS_AND_NEWLINE)
     486          return pos, ""
     487      if escape_id == "\\u":
     488          return parse_hex_char(src, pos, 4)
     489      if escape_id == "\\U":
     490          return parse_hex_char(src, pos, 8)
     491      try:
     492          return pos, BASIC_STR_ESCAPE_REPLACEMENTS[escape_id]
     493      except KeyError:
     494          raise suffixed_err(src, pos, "Unescaped '\\' in a string") from None
     495  
     496  
     497  def parse_basic_str_escape_multiline(src: str, pos: Pos) -> tuple[Pos, str]:
     498      return parse_basic_str_escape(src, pos, multiline=True)
     499  
     500  
     501  def parse_hex_char(src: str, pos: Pos, hex_len: int) -> tuple[Pos, str]:
     502      hex_str = src[pos : pos + hex_len]
     503      if len(hex_str) != hex_len or not HEXDIGIT_CHARS.issuperset(hex_str):
     504          raise suffixed_err(src, pos, "Invalid hex value")
     505      pos += hex_len
     506      hex_int = int(hex_str, 16)
     507      if not is_unicode_scalar_value(hex_int):
     508          raise suffixed_err(src, pos, "Escaped character is not a Unicode scalar value")
     509      return pos, chr(hex_int)
     510  
     511  
     512  def parse_literal_str(src: str, pos: Pos) -> tuple[Pos, str]:
     513      pos += 1  # Skip starting apostrophe
     514      start_pos = pos
     515      pos = skip_until(
     516          src, pos, "'", error_on=ILLEGAL_LITERAL_STR_CHARS, error_on_eof=True
     517      )
     518      return pos + 1, src[start_pos:pos]  # Skip ending apostrophe
     519  
     520  
     521  def parse_multiline_str(src: str, pos: Pos, *, literal: bool) -> tuple[Pos, str]:
     522      pos += 3
     523      if src.startswith("\n", pos):
     524          pos += 1
     525  
     526      if literal:
     527          delim = "'"
     528          end_pos = skip_until(
     529              src,
     530              pos,
     531              "'''",
     532              error_on=ILLEGAL_MULTILINE_LITERAL_STR_CHARS,
     533              error_on_eof=True,
     534          )
     535          result = src[pos:end_pos]
     536          pos = end_pos + 3
     537      else:
     538          delim = '"'
     539          pos, result = parse_basic_str(src, pos, multiline=True)
     540  
     541      # Add at maximum two extra apostrophes/quotes if the end sequence
     542      # is 4 or 5 chars long instead of just 3.
     543      if not src.startswith(delim, pos):
     544          return pos, result
     545      pos += 1
     546      if not src.startswith(delim, pos):
     547          return pos, result + delim
     548      pos += 1
     549      return pos, result + (delim * 2)
     550  
     551  
     552  def parse_basic_str(src: str, pos: Pos, *, multiline: bool) -> tuple[Pos, str]:
     553      if multiline:
     554          error_on = ILLEGAL_MULTILINE_BASIC_STR_CHARS
     555          parse_escapes = parse_basic_str_escape_multiline
     556      else:
     557          error_on = ILLEGAL_BASIC_STR_CHARS
     558          parse_escapes = parse_basic_str_escape
     559      result = ""
     560      start_pos = pos
     561      while True:
     562          try:
     563              char = src[pos]
     564          except IndexError:
     565              raise suffixed_err(src, pos, "Unterminated string") from None
     566          if char == '"':
     567              if not multiline:
     568                  return pos + 1, result + src[start_pos:pos]
     569              if src.startswith('"""', pos):
     570                  return pos + 3, result + src[start_pos:pos]
     571              pos += 1
     572              continue
     573          if char == "\\":
     574              result += src[start_pos:pos]
     575              pos, parsed_escape = parse_escapes(src, pos)
     576              result += parsed_escape
     577              start_pos = pos
     578              continue
     579          if char in error_on:
     580              raise suffixed_err(src, pos, f"Illegal character {char!r}")
     581          pos += 1
     582  
     583  
     584  def parse_value(  # noqa: C901
     585      src: str, pos: Pos, parse_float: ParseFloat
     586  ) -> tuple[Pos, Any]:
     587      try:
     588          char: str | None = src[pos]
     589      except IndexError:
     590          char = None
     591  
     592      # IMPORTANT: order conditions based on speed of checking and likelihood
     593  
     594      # Basic strings
     595      if char == '"':
     596          if src.startswith('"""', pos):
     597              return parse_multiline_str(src, pos, literal=False)
     598          return parse_one_line_basic_str(src, pos)
     599  
     600      # Literal strings
     601      if char == "'":
     602          if src.startswith("'''", pos):
     603              return parse_multiline_str(src, pos, literal=True)
     604          return parse_literal_str(src, pos)
     605  
     606      # Booleans
     607      if char == "t":
     608          if src.startswith("true", pos):
     609              return pos + 4, True
     610      if char == "f":
     611          if src.startswith("false", pos):
     612              return pos + 5, False
     613  
     614      # Arrays
     615      if char == "[":
     616          return parse_array(src, pos, parse_float)
     617  
     618      # Inline tables
     619      if char == "{":
     620          return parse_inline_table(src, pos, parse_float)
     621  
     622      # Dates and times
     623      datetime_match = RE_DATETIME.match(src, pos)
     624      if datetime_match:
     625          try:
     626              datetime_obj = match_to_datetime(datetime_match)
     627          except ValueError as e:
     628              raise suffixed_err(src, pos, "Invalid date or datetime") from e
     629          return datetime_match.end(), datetime_obj
     630      localtime_match = RE_LOCALTIME.match(src, pos)
     631      if localtime_match:
     632          return localtime_match.end(), match_to_localtime(localtime_match)
     633  
     634      # Integers and "normal" floats.
     635      # The regex will greedily match any type starting with a decimal
     636      # char, so needs to be located after handling of dates and times.
     637      number_match = RE_NUMBER.match(src, pos)
     638      if number_match:
     639          return number_match.end(), match_to_number(number_match, parse_float)
     640  
     641      # Special floats
     642      first_three = src[pos : pos + 3]
     643      if first_three in {"inf", "nan"}:
     644          return pos + 3, parse_float(first_three)
     645      first_four = src[pos : pos + 4]
     646      if first_four in {"-inf", "+inf", "-nan", "+nan"}:
     647          return pos + 4, parse_float(first_four)
     648  
     649      raise suffixed_err(src, pos, "Invalid value")
     650  
     651  
     652  def suffixed_err(src: str, pos: Pos, msg: str) -> TOMLDecodeError:
     653      """Return a `TOMLDecodeError` where error message is suffixed with
     654      coordinates in source."""
     655  
     656      def coord_repr(src: str, pos: Pos) -> str:
     657          if pos >= len(src):
     658              return "end of document"
     659          line = src.count("\n", 0, pos) + 1
     660          if line == 1:
     661              column = pos + 1
     662          else:
     663              column = pos - src.rindex("\n", 0, pos)
     664          return f"line {line}, column {column}"
     665  
     666      return TOMLDecodeError(f"{msg} (at {coord_repr(src, pos)})")
     667  
     668  
     669  def is_unicode_scalar_value(codepoint: int) -> bool:
     670      return (0 <= codepoint <= 55295) or (57344 <= codepoint <= 1114111)
     671  
     672  
     673  def make_safe_parse_float(parse_float: ParseFloat) -> ParseFloat:
     674      """A decorator to make `parse_float` safe.
     675  
     676      `parse_float` must not return dicts or lists, because these types
     677      would be mixed with parsed TOML tables and arrays, thus confusing
     678      the parser. The returned decorated callable raises `ValueError`
     679      instead of returning illegal types.
     680      """
     681      # The default `float` callable never returns illegal types. Optimize it.
     682      if parse_float is float:  # type: ignore[comparison-overlap]
     683          return float
     684  
     685      def safe_parse_float(float_str: str) -> Any:
     686          float_value = parse_float(float_str)
     687          if isinstance(float_value, (dict, list)):
     688              raise ValueError("parse_float must not return dicts or lists")
     689          return float_value
     690  
     691      return safe_parse_float