refactor: add tomllib preference

examples/pep723.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env -S viv run -s
+# /// pyproject
+# [run]
+# requires-python = ">=3.11"
+# dependencies = [
+#   "requests<3",
+#   "rich",
+# ]
+# ///
+
+import requests
+from rich import print
+
+resp = requests.get("https://peps.python.org/api/peps.json")
+data = resp.json()
+print([(k, v["title"]) for k, v in data.items()][:10])

scripts/vendor-tomli.py

@@ -0,0 +1,87 @@
+import re
+from pathlib import Path
+
+FILES = (
+    ("types", [[7, 11]]),
+    ("re", [[14, 107]]),
+    ("parser", [[20, 691]]),
+)
+
+TOMLI_DELIM = ("##### START VENDORED TOMLI #####", "##### END VENDORED TOMLI #####")
+
+TOMLI_PREFACE = """
+# MODIFIED FROM https://github.com/hukkin/tomli
+# see below for original license
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2021 Taneli Hukkinen
+# Licensed to PSF under a Contributor Agreement.
+"""
+
+VENDORED_IMPORTS = """
+import string  # noqa
+from collections.abc import Iterable  # noqa
+from functools import lru_cache  # noqa
+from datetime import date, datetime, time, timedelta, timezone, tzinfo  # noqa
+from types import MappingProxyType  # noqa
+from typing import IO, Any, Callable, NamedTuple  # noqa
+"""
+
+# REMOVE FOR ACTUAL VENDORED VERSION
+tomli_text = VENDORED_IMPORTS
+for f, slices in FILES:
+    text = Path(f"./tomli/src/tomli/_{f}.py").read_text()
+    for indices in slices:
+        tomli_text = "\n".join(
+            (
+                tomli_text,
+                # black can add back spaces if it wants
+                *[
+                    line
+                    for line in text.splitlines()[slice(*indices)]
+                    if line.strip("\r\n")
+                ],
+            )
+        )
+
+IDENT_PATTERN = r"^(?P<ident>[A-Z_]*) ="
+FUNC_PATTERN = r"^def (?P<function>[a-zA-Z_]+)\("
+
+idents = re.findall(IDENT_PATTERN, tomli_text, re.MULTILINE)
+funcs = re.findall(FUNC_PATTERN, tomli_text, re.MULTILINE)
+
+
+# TODO: USE ONE LOOP?
+for pat in idents + funcs:
+    tomli_text = re.sub(f"(?<!__tomli__){pat}", f"__tomli__{pat}", tomli_text)
+# for func in funcs:
+# tomli_text = re.sub(f"(?<!__tomli__){func}", f" __tomli__{func}", tomli_text)
+
+# tomli_text += "\n# fmt:on\n"
+tomli_text = "\n".join((TOMLI_PREFACE, tomli_text))
+
+viv_src = Path("../src/viv/viv.py")
+
+start, rest = re.split(TOMLI_DELIM[0], viv_src.read_text())
+_, rest = re.split(TOMLI_DELIM[1], viv_src.read_text())
+
+
+viv_src.write_text(
+    "\n".join(
+        (
+            start.strip(),
+            "\n",
+            TOMLI_DELIM[0],
+            tomli_text.strip(),
+            TOMLI_DELIM[1],
+            "\n",
+            rest.strip(),
+        )
+    )
+)
+#     re.sub(
+#     r"""\n##### START VENDORED TOMLI #####\n*.*\n*##### END VENDORED TOMLI #####\n""",
+#         re.escape(tomli_text),
+#         viv_src.read_text(),
+#         re.MULTILINE,
+#     )
+# )

src/viv/viv.py

@@ -21,7 +21,6 @@ import subprocess
 import sys
 import tempfile
 import threading
-import time
 import venv
 from argparse import (
     SUPPRESS,
@@ -37,6 +36,7 @@ from datetime import datetime
 from logging.handlers import RotatingFileHandler
 from pathlib import Path
 from textwrap import dedent, fill
+from time import sleep
 from types import TracebackType
 from typing import (
     Any,
@@ -53,7 +53,784 @@ from typing import (
     Union,
 )
 
-__version__ = "2023.1003-dev"
+__version__ = "2023.1003-pep723"
+
+
+##### START VENDORED TOMLI #####
+try:
+    from tomllib import loads as toml_loads
+except ImportError:
+    # MODIFIED FROM https://github.com/hukkin/tomli
+    # see below for original license
+    # SPDX-License-Identifier: MIT
+    # SPDX-FileCopyrightText: 2021 Taneli Hukkinen
+    # Licensed to PSF under a Contributor Agreement.
+    import string  # noqa
+    from collections.abc import Iterable  # noqa
+    from functools import lru_cache  # noqa
+    from datetime import date, datetime, time, timedelta, timezone, tzinfo  # noqa
+    from types import MappingProxyType  # noqa
+    from typing import IO, Any, Callable, NamedTuple  # noqa
+
+    ParseFloat = Callable[[str], Any]
+    Key = Tuple[str, ...]
+    Pos = int
+    # - 00:32:00.999999
+    # - 00:32:00
+    __tomli___TIME_RE_STR = (
+        r"([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9])(?:\.([0-9]{1,6})[0-9]*)?"
+    )
+    __tomli__RE_NUMBER = re.compile(
+        r"""
+    0
+    (?:
+        x[0-9A-Fa-f](?:_?[0-9A-Fa-f])*   # hex
+        |
+        b[01](?:_?[01])*                 # bin
+        |
+        o[0-7](?:_?[0-7])*               # oct
+    )
+    |
+    [+-]?(?:0|[1-9](?:_?[0-9])*)         # dec, integer part
+    (?P<floatpart>
+        (?:\.[0-9](?:_?[0-9])*)?         # optional fractional part
+        (?:[eE][+-]?[0-9](?:_?[0-9])*)?  # optional exponent part
+    )
+    """,
+        flags=re.VERBOSE,
+    )
+    __tomli__RE_LOCALTIME = re.compile(__tomli___TIME_RE_STR)
+    __tomli__RE_DATETIME = re.compile(
+        rf"""
+    ([0-9]{{4}})-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01])  # date, e.g. 1988-10-27
+    (?:
+        [Tt ]
+        {__tomli___TIME_RE_STR}
+        (?:([Zz])|([+-])([01][0-9]|2[0-3]):([0-5][0-9]))?  # optional time offset
+    )?
+    """,
+        flags=re.VERBOSE,
+    )
+
+    def __tomli__match_to_datetime(match: re.Match) -> datetime | date:
+        """Convert a `__tomli__RE_DATETIME` match to `datetime.datetime`
+        or `datetime.date`.
+        Raises ValueError if the match does not correspond to a valid date
+        or datetime.
+        """
+        (
+            year_str,
+            month_str,
+            day_str,
+            hour_str,
+            minute_str,
+            sec_str,
+            micros_str,
+            zulu_time,
+            offset_sign_str,
+            offset_hour_str,
+            offset_minute_str,
+        ) = match.groups()
+        year, month, day = int(year_str), int(month_str), int(day_str)
+        if hour_str is None:
+            return date(year, month, day)
+        hour, minute, sec = int(hour_str), int(minute_str), int(sec_str)
+        micros = int(micros_str.ljust(6, "0")) if micros_str else 0
+        if offset_sign_str:
+            tz: tzinfo | None = __tomli__cached_tz(
+                offset_hour_str, offset_minute_str, offset_sign_str
+            )
+        elif zulu_time:
+            tz = timezone.utc
+        else:  # local date-time
+            tz = None
+        return datetime(year, month, day, hour, minute, sec, micros, tzinfo=tz)
+
+    @lru_cache(maxsize=None)
+    def __tomli__cached_tz(hour_str: str, minute_str: str, sign_str: str) -> timezone:
+        sign = 1 if sign_str == "+" else -1
+        return timezone(
+            timedelta(
+                hours=sign * int(hour_str),
+                minutes=sign * int(minute_str),
+            )
+        )
+
+    def __tomli__match_to_localtime(match: re.Match) -> time:
+        hour_str, minute_str, sec_str, micros_str = match.groups()
+        micros = int(micros_str.ljust(6, "0")) if micros_str else 0
+        return time(int(hour_str), int(minute_str), int(sec_str), micros)
+
+    def __tomli__match_to_number(match: re.Match, parse_float: ParseFloat) -> Any:
+        if match.group("floatpart"):
+            return parse_float(match.group())
+        return int(match.group(), 0)
+
+    __tomli__ASCII_CTRL = frozenset(chr(i) for i in range(32)) | frozenset(chr(127))
+    # Neither of these sets include quotation mark or backslash. They are
+    # currently handled as separate cases in the parser functions.
+    __tomli__ILLEGAL_BASIC_STR_CHARS = __tomli__ASCII_CTRL - frozenset("\t")
+    __tomli__ILLEGAL_MULTILINE_BASIC_STR_CHARS = __tomli__ASCII_CTRL - frozenset("\t\n")
+    __tomli__ILLEGAL_LITERAL_STR_CHARS = __tomli__ILLEGAL_BASIC_STR_CHARS
+    __tomli__ILLEGAL_MULTILINE_LITERAL_STR_CHARS = (
+        __tomli__ILLEGAL_MULTILINE_BASIC_STR_CHARS
+    )
+    __tomli__ILLEGAL_COMMENT_CHARS = __tomli__ILLEGAL_BASIC_STR_CHARS
+    __tomli__TOML_WS = frozenset(" \t")
+    __tomli__TOML_WS_AND_NEWLINE = __tomli__TOML_WS | frozenset("\n")
+    __tomli__BARE_KEY_CHARS = frozenset(string.ascii_letters + string.digits + "-_")
+    __tomli__KEY_INITIAL_CHARS = __tomli__BARE_KEY_CHARS | frozenset("\"'")
+    __tomli__HEXDIGIT_CHARS = frozenset(string.hexdigits)
+    __tomli__BASIC_STR_ESCAPE_REPLACEMENTS = MappingProxyType(
+        {
+            "\\b": "\u0008",  # backspace
+            "\\t": "\u0009",  # tab
+            "\\n": "\u000A",  # linefeed
+            "\\f": "\u000C",  # form feed
+            "\\r": "\u000D",  # carriage return
+            '\\"': "\u0022",  # quote
+            "\\\\": "\u005C",  # backslash
+        }
+    )
+
+    class TOMLDecodeError(ValueError):
+        """An error raised if a document is not valid TOML."""
+
+    def __tomli__load(
+        __fp: IO[bytes], *, parse_float: ParseFloat = float
+    ) -> dict[str, Any]:
+        """Parse TOML from a binary file object."""
+        b = __fp.read()
+        try:
+            s = b.decode()
+        except AttributeError:
+            raise TypeError(
+                "File must be opened in binary mode, e.g. use `open('foo.toml', 'rb')`"
+            ) from None
+        return __tomli__loads(s, parse_float=parse_float)
+
+    def __tomli__loads(
+        __s: str, *, parse_float: ParseFloat = float
+    ) -> dict[str, Any]:  # noqa: C901
+        """Parse TOML from a string."""
+        # The spec allows converting "\r\n" to "\n", even in string
+        # literals. Let's do so to simplify parsing.
+        src = __s.replace("\r\n", "\n")
+        pos = 0
+        out = Output(NestedDict(), Flags())
+        header: Key = ()
+        parse_float = __tomli__make_safe_parse_float(parse_float)
+        # Parse one statement at a time
+        # (typically means one line in TOML source)
+        while True:
+            # 1. Skip line leading whitespace
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+            # 2. Parse rules. Expect one of the following:
+            #    - end of file
+            #    - end of line
+            #    - comment
+            #    - key/value pair
+            #    - append dict to list (and move to its namespace)
+            #    - create dict (and move to its namespace)
+            # Skip trailing whitespace when applicable.
+            try:
+                char = src[pos]
+            except IndexError:
+                break
+            if char == "\n":
+                pos += 1
+                continue
+            if char in __tomli__KEY_INITIAL_CHARS:
+                pos = __tomli__key_value_rule(src, pos, out, header, parse_float)
+                pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+            elif char == "[":
+                try:
+                    second_char: str | None = src[pos + 1]
+                except IndexError:
+                    second_char = None
+                out.flags.finalize_pending()
+                if second_char == "[":
+                    pos, header = __tomli__create_list_rule(src, pos, out)
+                else:
+                    pos, header = __tomli__create_dict_rule(src, pos, out)
+                pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+            elif char != "#":
+                raise __tomli__suffixed_err(src, pos, "Invalid statement")
+            # 3. Skip comment
+            pos = __tomli__skip_comment(src, pos)
+            # 4. Expect end of line or end of file
+            try:
+                char = src[pos]
+            except IndexError:
+                break
+            if char != "\n":
+                raise __tomli__suffixed_err(
+                    src, pos, "Expected newline or end of document after a statement"
+                )
+            pos += 1
+        return out.data.dict
+
+    class Flags:
+        """Flags that map to parsed keys/namespaces."""
+
+        # Marks an immutable namespace (inline array or inline table).
+        FROZEN = 0
+        # Marks a nest that has been explicitly created and can no longer
+        # be opened using the "[table]" syntax.
+        EXPLICIT_NEST = 1
+
+        def __init__(self) -> None:
+            self._flags: dict[str, dict] = {}
+            self._pending_flags: set[tuple[Key, int]] = set()
+
+        def add_pending(self, key: Key, flag: int) -> None:
+            self._pending_flags.add((key, flag))
+
+        def finalize_pending(self) -> None:
+            for key, flag in self._pending_flags:
+                self.set(key, flag, recursive=False)
+            self._pending_flags.clear()
+
+        def unset_all(self, key: Key) -> None:
+            cont = self._flags
+            for k in key[:-1]:
+                if k not in cont:
+                    return
+                cont = cont[k]["nested"]
+            cont.pop(key[-1], None)
+
+        def set(self, key: Key, flag: int, *, recursive: bool) -> None:  # noqa: A003
+            cont = self._flags
+            key_parent, key_stem = key[:-1], key[-1]
+            for k in key_parent:
+                if k not in cont:
+                    cont[k] = {"flags": set(), "recursive_flags": set(), "nested": {}}
+                cont = cont[k]["nested"]
+            if key_stem not in cont:
+                cont[key_stem] = {
+                    "flags": set(),
+                    "recursive_flags": set(),
+                    "nested": {},
+                }
+            cont[key_stem]["recursive_flags" if recursive else "flags"].add(flag)
+
+        def is_(self, key: Key, flag: int) -> bool:
+            if not key:
+                return False  # document root has no flags
+            cont = self._flags
+            for k in key[:-1]:
+                if k not in cont:
+                    return False
+                inner_cont = cont[k]
+                if flag in inner_cont["recursive_flags"]:
+                    return True
+                cont = inner_cont["nested"]
+            key_stem = key[-1]
+            if key_stem in cont:
+                cont = cont[key_stem]
+                return flag in cont["flags"] or flag in cont["recursive_flags"]
+            return False
+
+    class NestedDict:
+        def __init__(self) -> None:
+            # The parsed content of the TOML document
+            self.dict: dict[str, Any] = {}
+
+        def get_or_create_nest(
+            self,
+            key: Key,
+            *,
+            access_lists: bool = True,
+        ) -> dict:
+            cont: Any = self.dict
+            for k in key:
+                if k not in cont:
+                    cont[k] = {}
+                cont = cont[k]
+                if access_lists and isinstance(cont, list):
+                    cont = cont[-1]
+                if not isinstance(cont, dict):
+                    raise KeyError("There is no nest behind this key")
+            return cont
+
+        def append_nest_to_list(self, key: Key) -> None:
+            cont = self.get_or_create_nest(key[:-1])
+            last_key = key[-1]
+            if last_key in cont:
+                list_ = cont[last_key]
+                if not isinstance(list_, list):
+                    raise KeyError("An object other than list found behind this key")
+                list_.append({})
+            else:
+                cont[last_key] = [{}]
+
+    class Output(NamedTuple):
+        data: NestedDict
+        flags: Flags
+
+    def __tomli__skip_chars(src: str, pos: Pos, chars: Iterable[str]) -> Pos:
+        try:
+            while src[pos] in chars:
+                pos += 1
+        except IndexError:
+            pass
+        return pos
+
+    def __tomli__skip_until(
+        src: str,
+        pos: Pos,
+        expect: str,
+        *,
+        error_on: frozenset[str],
+        error_on_eof: bool,
+    ) -> Pos:
+        try:
+            new_pos = src.index(expect, pos)
+        except ValueError:
+            new_pos = len(src)
+            if error_on_eof:
+                raise __tomli__suffixed_err(
+                    src, new_pos, f"Expected {expect!r}"
+                ) from None
+        if not error_on.isdisjoint(src[pos:new_pos]):
+            while src[pos] not in error_on:
+                pos += 1
+            raise __tomli__suffixed_err(
+                src, pos, f"Found invalid character {src[pos]!r}"
+            )
+        return new_pos
+
+    def __tomli__skip_comment(src: str, pos: Pos) -> Pos:
+        try:
+            char: str | None = src[pos]
+        except IndexError:
+            char = None
+        if char == "#":
+            return __tomli__skip_until(
+                src,
+                pos + 1,
+                "\n",
+                error_on=__tomli__ILLEGAL_COMMENT_CHARS,
+                error_on_eof=False,
+            )
+        return pos
+
+    def __tomli__skip_comments_and_array_ws(src: str, pos: Pos) -> Pos:
+        while True:
+            pos_before_skip = pos
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS_AND_NEWLINE)
+            pos = __tomli__skip_comment(src, pos)
+            if pos == pos_before_skip:
+                return pos
+
+    def __tomli__create_dict_rule(src: str, pos: Pos, out: Output) -> tuple[Pos, Key]:
+        pos += 1  # Skip "["
+        pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+        pos, key = __tomli__parse_key(src, pos)
+        if out.flags.is_(key, Flags.EXPLICIT_NEST) or out.flags.is_(key, Flags.FROZEN):
+            raise __tomli__suffixed_err(src, pos, f"Cannot declare {key} twice")
+        out.flags.set(key, Flags.EXPLICIT_NEST, recursive=False)
+        try:
+            out.data.get_or_create_nest(key)
+        except KeyError:
+            raise __tomli__suffixed_err(src, pos, "Cannot overwrite a value") from None
+        if not src.startswith("]", pos):
+            raise __tomli__suffixed_err(
+                src, pos, "Expected ']' at the end of a table declaration"
+            )
+        return pos + 1, key
+
+    def __tomli__create_list_rule(src: str, pos: Pos, out: Output) -> tuple[Pos, Key]:
+        pos += 2  # Skip "[["
+        pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+        pos, key = __tomli__parse_key(src, pos)
+        if out.flags.is_(key, Flags.FROZEN):
+            raise __tomli__suffixed_err(
+                src, pos, f"Cannot mutate immutable namespace {key}"
+            )
+        # Free the namespace now that it points to another empty list item...
+        out.flags.unset_all(key)
+        # ...but this key precisely is still prohibited from table declaration
+        out.flags.set(key, Flags.EXPLICIT_NEST, recursive=False)
+        try:
+            out.data.append_nest_to_list(key)
+        except KeyError:
+            raise __tomli__suffixed_err(src, pos, "Cannot overwrite a value") from None
+        if not src.startswith("]]", pos):
+            raise __tomli__suffixed_err(
+                src, pos, "Expected ']]' at the end of an array declaration"
+            )
+        return pos + 2, key
+
+    def __tomli__key_value_rule(
+        src: str, pos: Pos, out: Output, header: Key, parse_float: ParseFloat
+    ) -> Pos:
+        pos, key, value = __tomli__parse_key_value_pair(src, pos, parse_float)
+        key_parent, key_stem = key[:-1], key[-1]
+        abs_key_parent = header + key_parent
+        relative_path_cont_keys = (header + key[:i] for i in range(1, len(key)))
+        for cont_key in relative_path_cont_keys:
+            # Check that dotted key syntax does not redefine an existing table
+            if out.flags.is_(cont_key, Flags.EXPLICIT_NEST):
+                raise __tomli__suffixed_err(
+                    src, pos, f"Cannot redefine namespace {cont_key}"
+                )
+            # Containers in the relative path can't be opened with the table syntax or
+            # dotted key/value syntax in following table sections.
+            out.flags.add_pending(cont_key, Flags.EXPLICIT_NEST)
+        if out.flags.is_(abs_key_parent, Flags.FROZEN):
+            raise __tomli__suffixed_err(
+                src, pos, f"Cannot mutate immutable namespace {abs_key_parent}"
+            )
+        try:
+            nest = out.data.get_or_create_nest(abs_key_parent)
+        except KeyError:
+            raise __tomli__suffixed_err(src, pos, "Cannot overwrite a value") from None
+        if key_stem in nest:
+            raise __tomli__suffixed_err(src, pos, "Cannot overwrite a value")
+        # Mark inline table and array namespaces recursively immutable
+        if isinstance(value, (dict, list)):
+            out.flags.set(header + key, Flags.FROZEN, recursive=True)
+        nest[key_stem] = value
+        return pos
+
+    def __tomli__parse_key_value_pair(
+        src: str, pos: Pos, parse_float: ParseFloat
+    ) -> tuple[Pos, Key, Any]:
+        pos, key = __tomli__parse_key(src, pos)
+        try:
+            char: str | None = src[pos]
+        except IndexError:
+            char = None
+        if char != "=":
+            raise __tomli__suffixed_err(
+                src, pos, "Expected '=' after a key in a key/value pair"
+            )
+        pos += 1
+        pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+        pos, value = __tomli__parse_value(src, pos, parse_float)
+        return pos, key, value
+
+    def __tomli__parse_key(src: str, pos: Pos) -> tuple[Pos, Key]:
+        pos, key_part = __tomli__parse_key_part(src, pos)
+        key: Key = (key_part,)
+        pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+        while True:
+            try:
+                char: str | None = src[pos]
+            except IndexError:
+                char = None
+            if char != ".":
+                return pos, key
+            pos += 1
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+            pos, key_part = __tomli__parse_key_part(src, pos)
+            key += (key_part,)
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+
+    def __tomli__parse_key_part(src: str, pos: Pos) -> tuple[Pos, str]:
+        try:
+            char: str | None = src[pos]
+        except IndexError:
+            char = None
+        if char in __tomli__BARE_KEY_CHARS:
+            start_pos = pos
+            pos = __tomli__skip_chars(src, pos, __tomli__BARE_KEY_CHARS)
+            return pos, src[start_pos:pos]
+        if char == "'":
+            return __tomli__parse_literal_str(src, pos)
+        if char == '"':
+            return __tomli__parse_one_line_basic_str(src, pos)
+        raise __tomli__suffixed_err(
+            src, pos, "Invalid initial character for a key part"
+        )
+
+    def __tomli__parse_one_line_basic_str(src: str, pos: Pos) -> tuple[Pos, str]:
+        pos += 1
+        return __tomli__parse_basic_str(src, pos, multiline=False)
+
+    def __tomli__parse_array(
+        src: str, pos: Pos, parse_float: ParseFloat
+    ) -> tuple[Pos, list]:
+        pos += 1
+        array: list = []
+        pos = __tomli__skip_comments_and_array_ws(src, pos)
+        if src.startswith("]", pos):
+            return pos + 1, array
+        while True:
+            pos, val = __tomli__parse_value(src, pos, parse_float)
+            array.append(val)
+            pos = __tomli__skip_comments_and_array_ws(src, pos)
+            c = src[pos : pos + 1]
+            if c == "]":
+                return pos + 1, array
+            if c != ",":
+                raise __tomli__suffixed_err(src, pos, "Unclosed array")
+            pos += 1
+            pos = __tomli__skip_comments_and_array_ws(src, pos)
+            if src.startswith("]", pos):
+                return pos + 1, array
+
+    def __tomli__parse_inline_table(
+        src: str, pos: Pos, parse_float: ParseFloat
+    ) -> tuple[Pos, dict]:
+        pos += 1
+        nested_dict = NestedDict()
+        flags = Flags()
+        pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+        if src.startswith("}", pos):
+            return pos + 1, nested_dict.dict
+        while True:
+            pos, key, value = __tomli__parse_key_value_pair(src, pos, parse_float)
+            key_parent, key_stem = key[:-1], key[-1]
+            if flags.is_(key, Flags.FROZEN):
+                raise __tomli__suffixed_err(
+                    src, pos, f"Cannot mutate immutable namespace {key}"
+                )
+            try:
+                nest = nested_dict.get_or_create_nest(key_parent, access_lists=False)
+            except KeyError:
+                raise __tomli__suffixed_err(
+                    src, pos, "Cannot overwrite a value"
+                ) from None
+            if key_stem in nest:
+                raise __tomli__suffixed_err(
+                    src, pos, f"Duplicate inline table key {key_stem!r}"
+                )
+            nest[key_stem] = value
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+            c = src[pos : pos + 1]
+            if c == "}":
+                return pos + 1, nested_dict.dict
+            if c != ",":
+                raise __tomli__suffixed_err(src, pos, "Unclosed inline table")
+            if isinstance(value, (dict, list)):
+                flags.set(key, Flags.FROZEN, recursive=True)
+            pos += 1
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+
+    def __tomli__parse_basic_str_escape(
+        src: str, pos: Pos, *, multiline: bool = False
+    ) -> tuple[Pos, str]:
+        escape_id = src[pos : pos + 2]
+        pos += 2
+        if multiline and escape_id in {"\\ ", "\\\t", "\\\n"}:
+            # Skip whitespace until next non-whitespace character or end of
+            # the doc. Error if non-whitespace is found before newline.
+            if escape_id != "\\\n":
+                pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS)
+                try:
+                    char = src[pos]
+                except IndexError:
+                    return pos, ""
+                if char != "\n":
+                    raise __tomli__suffixed_err(src, pos, "Unescaped '\\' in a string")
+                pos += 1
+            pos = __tomli__skip_chars(src, pos, __tomli__TOML_WS_AND_NEWLINE)
+            return pos, ""
+        if escape_id == "\\u":
+            return __tomli__parse_hex_char(src, pos, 4)
+        if escape_id == "\\U":
+            return __tomli__parse_hex_char(src, pos, 8)
+        try:
+            return pos, __tomli__BASIC_STR_ESCAPE_REPLACEMENTS[escape_id]
+        except KeyError:
+            raise __tomli__suffixed_err(
+                src, pos, "Unescaped '\\' in a string"
+            ) from None
+
+    def __tomli__parse_basic_str_escape_multiline(
+        src: str, pos: Pos
+    ) -> tuple[Pos, str]:
+        return __tomli__parse_basic_str_escape(src, pos, multiline=True)
+
+    def __tomli__parse_hex_char(src: str, pos: Pos, hex_len: int) -> tuple[Pos, str]:
+        hex_str = src[pos : pos + hex_len]
+        if len(hex_str) != hex_len or not __tomli__HEXDIGIT_CHARS.issuperset(hex_str):
+            raise __tomli__suffixed_err(src, pos, "Invalid hex value")
+        pos += hex_len
+        hex_int = int(hex_str, 16)
+        if not __tomli__is_unicode_scalar_value(hex_int):
+            raise __tomli__suffixed_err(
+                src, pos, "Escaped character is not a Unicode scalar value"
+            )
+        return pos, chr(hex_int)
+
+    def __tomli__parse_literal_str(src: str, pos: Pos) -> tuple[Pos, str]:
+        pos += 1  # Skip starting apostrophe
+        start_pos = pos
+        pos = __tomli__skip_until(
+            src,
+            pos,
+            "'",
+            error_on=__tomli__ILLEGAL_LITERAL_STR_CHARS,
+            error_on_eof=True,
+        )
+        return pos + 1, src[start_pos:pos]  # Skip ending apostrophe
+
+    def __tomli__parse_multiline_str(
+        src: str, pos: Pos, *, literal: bool
+    ) -> tuple[Pos, str]:
+        pos += 3
+        if src.startswith("\n", pos):
+            pos += 1
+        if literal:
+            delim = "'"
+            end_pos = __tomli__skip_until(
+                src,
+                pos,
+                "'''",
+                error_on=__tomli__ILLEGAL_MULTILINE_LITERAL_STR_CHARS,
+                error_on_eof=True,
+            )
+            result = src[pos:end_pos]
+            pos = end_pos + 3
+        else:
+            delim = '"'
+            pos, result = __tomli__parse_basic_str(src, pos, multiline=True)
+        # Add at maximum two extra apostrophes/quotes if the end sequence
+        # is 4 or 5 chars long instead of just 3.
+        if not src.startswith(delim, pos):
+            return pos, result
+        pos += 1
+        if not src.startswith(delim, pos):
+            return pos, result + delim
+        pos += 1
+        return pos, result + (delim * 2)
+
+    def __tomli__parse_basic_str(
+        src: str, pos: Pos, *, multiline: bool
+    ) -> tuple[Pos, str]:
+        if multiline:
+            error_on = __tomli__ILLEGAL_MULTILINE_BASIC_STR_CHARS
+            parse_escapes = __tomli__parse_basic_str_escape_multiline
+        else:
+            error_on = __tomli__ILLEGAL_BASIC_STR_CHARS
+            parse_escapes = __tomli__parse_basic_str_escape
+        result = ""
+        start_pos = pos
+        while True:
+            try:
+                char = src[pos]
+            except IndexError:
+                raise __tomli__suffixed_err(src, pos, "Unterminated string") from None
+            if char == '"':
+                if not multiline:
+                    return pos + 1, result + src[start_pos:pos]
+                if src.startswith('"""', pos):
+                    return pos + 3, result + src[start_pos:pos]
+                pos += 1
+                continue
+            if char == "\\":
+                result += src[start_pos:pos]
+                pos, parsed_escape = parse_escapes(src, pos)
+                result += parsed_escape
+                start_pos = pos
+                continue
+            if char in error_on:
+                raise __tomli__suffixed_err(src, pos, f"Illegal character {char!r}")
+            pos += 1
+
+    def __tomli__parse_value(  # noqa: C901
+        src: str, pos: Pos, parse_float: ParseFloat
+    ) -> tuple[Pos, Any]:
+        try:
+            char: str | None = src[pos]
+        except IndexError:
+            char = None
+        # IMPORTANT: order conditions based on speed of checking and likelihood
+        # Basic strings
+        if char == '"':
+            if src.startswith('"""', pos):
+                return __tomli__parse_multiline_str(src, pos, literal=False)
+            return __tomli__parse_one_line_basic_str(src, pos)
+        # Literal strings
+        if char == "'":
+            if src.startswith("'''", pos):
+                return __tomli__parse_multiline_str(src, pos, literal=True)
+            return __tomli__parse_literal_str(src, pos)
+        # Booleans
+        if char == "t":
+            if src.startswith("true", pos):
+                return pos + 4, True
+        if char == "f":
+            if src.startswith("false", pos):
+                return pos + 5, False
+        # Arrays
+        if char == "[":
+            return __tomli__parse_array(src, pos, parse_float)
+        # Inline tables
+        if char == "{":
+            return __tomli__parse_inline_table(src, pos, parse_float)
+        # Dates and times
+        datetime_match = __tomli__RE_DATETIME.match(src, pos)
+        if datetime_match:
+            try:
+                datetime_obj = __tomli__match_to_datetime(datetime_match)
+            except ValueError as e:
+                raise __tomli__suffixed_err(src, pos, "Invalid date or datetime") from e
+            return datetime_match.end(), datetime_obj
+        localtime_match = __tomli__RE_LOCALTIME.match(src, pos)
+        if localtime_match:
+            return localtime_match.end(), __tomli__match_to_localtime(localtime_match)
+        # Integers and "normal" floats.
+        # The regex will greedily match any type starting with a decimal
+        # char, so needs to be located after handling of dates and times.
+        number_match = __tomli__RE_NUMBER.match(src, pos)
+        if number_match:
+            return number_match.end(), __tomli__match_to_number(
+                number_match, parse_float
+            )
+        # Special floats
+        first_three = src[pos : pos + 3]
+        if first_three in {"inf", "nan"}:
+            return pos + 3, parse_float(first_three)
+        first_four = src[pos : pos + 4]
+        if first_four in {"-inf", "+inf", "-nan", "+nan"}:
+            return pos + 4, parse_float(first_four)
+        raise __tomli__suffixed_err(src, pos, "Invalid value")
+
+    def __tomli__suffixed_err(src: str, pos: Pos, msg: str) -> TOMLDecodeError:
+        """Return a `TOMLDecodeError` where error message is suffixed with
+        coordinates in source."""
+
+        def coord_repr(src: str, pos: Pos) -> str:
+            if pos >= len(src):
+                return "end of document"
+            line = src.count("\n", 0, pos) + 1
+            if line == 1:
+                column = pos + 1
+            else:
+                column = pos - src.rindex("\n", 0, pos)
+            return f"line {line}, column {column}"
+
+        return TOMLDecodeError(f"{msg} (at {coord_repr(src, pos)})")
+
+    def __tomli__is_unicode_scalar_value(codepoint: int) -> bool:
+        return (0 <= codepoint <= 55295) or (57344 <= codepoint <= 1114111)
+
+    def __tomli__make_safe_parse_float(parse_float: ParseFloat) -> ParseFloat:
+        """A decorator to make `parse_float` safe.
+        `parse_float` must not return dicts or lists, because these types
+        would be mixed with parsed TOML tables and arrays, thus confusing
+        the parser. The returned decorated callable raises `ValueError`
+        instead of returning illegal types.
+        """
+        # The default `float` callable never returns illegal types. Optimize it.
+        if parse_float is float:
+            return float
+
+        def safe_parse_float(float_str: str) -> Any:
+            float_value = parse_float(float_str)
+            if isinstance(float_value, (dict, list)):
+                raise ValueError("parse_float must not return dicts or lists")
+            return float_value
+
+        return safe_parse_float
+
+    toml_loads = __tomli__loads
+
+##### END VENDORED TOMLI #####
 
 
 class Spinner:
@@ -89,7 +866,7 @@ class Spinner:
     def spinner_task(self) -> None:
         while self.busy:
             self.write_next()
-            time.sleep(self.delay)
+            sleep(self.delay)
             self.remove_spinner()
 
     def __enter__(self) -> None:
@@ -1217,27 +1994,47 @@ def uses_viv(txt: str) -> bool:
     )
 
 
-DEPENDENCY_BLOCK_MARKER = r"(?i)^#\s+script\s+dependencies:\s*$"
+METADATA_BLOCK = (
+    r"(?m)^# /// (?P<type>[a-zA-Z0-9-]+)$\s(?P<content>(^#(| .*)$\s)+)^# ///$"
+)
 
 
-def read_dependency_block(txt: str) -> Generator[str, None, None]:
-    lines = iter(txt.splitlines())
-    for line in lines:
-        if re.match(DEPENDENCY_BLOCK_MARKER, line):
-            for line in lines:
-                if not line.startswith("#"):
-                    break
-                # Remove comments. An inline comment is introduced by
-                # a hash, which must be preceded and followed by a
-                # space. The initial hash will be skipped as it has
-                # no space before it.
-                line = line.split(" # ", maxsplit=1)[0]
-                line = line[1:].strip()
-                if not line:
-                    continue
-                # let pip handle the requirement errors
-                yield line
-            break
+def read_metadata_block(script: str) -> dict:
+    name = "pyproject"
+    matches = list(
+        filter(lambda m: m.group("type") == name, re.finditer(METADATA_BLOCK, script))
+    )
+    if len(matches) > 1:
+        raise ValueError(f"Multiple {name} blocks found")
+    elif len(matches) == 1:
+        return toml_loads(
+            "\n".join((line[2:] for line in matches[0].group(0).splitlines()[1:-1]))
+        )
+    else:
+        return {}
+
+
+# DEPENDENCY_BLOCK_MARKER = r"(?i)^#\s+script\s+dependencies:\s*$"
+#
+# def read_dependency_block(txt: str) -> Generator[str, None, None]:
+#     lines = iter(txt.splitlines())
+#     for line in lines:
+#         if re.match(DEPENDENCY_BLOCK_MARKER, line):
+#             for line in lines:
+#                 if not line.startswith("#"):
+#                     break
+#                 # Remove comments. An inline comment is introduced by
+#                 # a hash, which must be preceded and followed by a
+#                 # space. The initial hash will be skipped as it has
+#                 # no space before it.
+#                 line = line.split(" # ", maxsplit=1)[0]
+#                 line = line[1:].strip()
+#                 if not line:
+#                     continue
+#                 # let pip handle the requirement errors
+#                 yield line
+#             break
+#
 
 
 def _parse_date(txt: str) -> datetime:
@@ -1749,7 +2546,9 @@ class Viv:
                 script_text = fetch_script(script)
 
             viv_used = uses_viv(script_text)
-            deps = list(read_dependency_block(script_text))
+            deps = (
+                read_metadata_block(script_text).get("run", {}).get("dependencies", [])
+            )
 
             if viv_used and deps:
                 error(