gh-111201: A new Python REPL (GH-111567)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>
Co-authored-by: Marta Gómez Macías <mgmacias@google.com>
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

1 files changed, 157 insertions, 0 deletions

diff --git a/Lib/_pyrepl/simple_interact.py b/Lib/_pyrepl/simple_interact.py
new file mode 100644
index 00000000000..ce79d0d547e
--- /dev/null
+++ b/Lib/_pyrepl/simple_interact.py
@@ -0,0 +1,157 @@
+#   Copyright 2000-2010 Michael Hudson-Doyle <micahel@gmail.com>
+#                       Armin Rigo
+#
+#                        All Rights Reserved
+#
+#
+# Permission to use, copy, modify, and distribute this software and
+# its documentation for any purpose is hereby granted without fee,
+# provided that the above copyright notice appear in all copies and
+# that both that copyright notice and this permission notice appear in
+# supporting documentation.
+#
+# THE AUTHOR MICHAEL HUDSON DISCLAIMS ALL WARRANTIES WITH REGARD TO
+# THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+# AND FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
+# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
+# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+"""This is an alternative to python_reader which tries to emulate
+the CPython prompt as closely as possible, with the exception of
+allowing multiline input and multiline history entries.
+"""
+
+from __future__ import annotations
+
+import _colorize  # type: ignore[import-not-found]
+import _sitebuiltins
+import linecache
+import sys
+import code
+from types import ModuleType
+
+from .console import Event
+from .readline import _get_reader, multiline_input
+from .unix_console import _error
+
+
+def check() -> str:
+    """Returns the error message if there is a problem initializing the state."""
+    try:
+        _get_reader()
+    except _error as e:
+        return str(e) or repr(e) or "unknown error"
+    return ""
+
+
+def _strip_final_indent(text: str) -> str:
+    # kill spaces and tabs at the end, but only if they follow '\n'.
+    # meant to remove the auto-indentation only (although it would of
+    # course also remove explicitly-added indentation).
+    short = text.rstrip(" \t")
+    n = len(short)
+    if n > 0 and text[n - 1] == "\n":
+        return short
+    return text
+
+
+REPL_COMMANDS = {
+    "exit": _sitebuiltins.Quitter('exit', ''),
+    "quit": _sitebuiltins.Quitter('quit' ,''),
+    "copyright": _sitebuiltins._Printer('copyright', sys.copyright),
+    "help": "help",
+}
+
+class InteractiveColoredConsole(code.InteractiveConsole):
+    def __init__(
+        self,
+        locals: dict[str, object] | None = None,
+        filename: str = "<console>",
+        *,
+        local_exit: bool = False,
+    ) -> None:
+        super().__init__(locals=locals, filename=filename, local_exit=local_exit)  # type: ignore[call-arg]
+        self.can_colorize = _colorize.can_colorize()
+
+    def showtraceback(self):
+        super().showtraceback(colorize=self.can_colorize)
+
+
+def run_multiline_interactive_console(
+    mainmodule: ModuleType | None= None, future_flags: int = 0
+) -> None:
+    import code
+    import __main__
+    from .readline import _setup
+    _setup()
+
+    mainmodule = mainmodule or __main__
+    console = InteractiveColoredConsole(mainmodule.__dict__, filename="<stdin>")
+    if future_flags:
+        console.compile.compiler.flags |= future_flags
+
+    input_n = 0
+
+    def maybe_run_command(statement: str) -> bool:
+        statement = statement.strip()
+        if statement in console.locals or statement not in REPL_COMMANDS:
+            return False
+
+        reader = _get_reader()
+        reader.history.pop()  # skip internal commands in history
+        command = REPL_COMMANDS[statement]
+        if callable(command):
+            command()
+            return True
+
+        if isinstance(command, str):
+            # Internal readline commands require a prepared reader like
+            # inside multiline_input.
+            reader.prepare()
+            reader.refresh()
+            reader.do_cmd((command, [statement]))
+            reader.restore()
+            return True
+
+        return False
+
+    def more_lines(unicodetext: str) -> bool:
+        # ooh, look at the hack:
+        src = _strip_final_indent(unicodetext)
+        try:
+            code = console.compile(src, "<stdin>", "single")
+        except (OverflowError, SyntaxError, ValueError):
+            return False
+        else:
+            return code is None
+
+    while 1:
+        try:
+            try:
+                sys.stdout.flush()
+            except Exception:
+                pass
+
+            ps1 = getattr(sys, "ps1", ">>> ")
+            ps2 = getattr(sys, "ps2", "... ")
+            try:
+                statement = multiline_input(more_lines, ps1, ps2)
+            except EOFError:
+                break
+
+            if maybe_run_command(statement):
+                continue
+
+            input_name = f"<python-input-{input_n}>"
+            linecache._register_code(input_name, statement, "<stdin>")  # type: ignore[attr-defined]
+            more = console.push(_strip_final_indent(statement), filename=input_name)  # type: ignore[call-arg]
+            assert not more
+            input_n += 1
+        except KeyboardInterrupt:
+            console.write("\nKeyboardInterrupt\n")
+            console.resetbuffer()
+        except MemoryError:
+            console.write("\nMemoryError\n")
+            console.resetbuffer()