Python 3.14: Cool New Features (WIP)

python-314/README.md

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+# Python 3.14: Cool New Features for You to Try
+
+The materials contained in this folder are designed to complement the Real Python tutorial [Python 3.14: Cool New Features for You to Try](https://realpython.com/python314-new-features/).

python-314/fib.py

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+def fib(n):
+    print(f"Calculating fib({n})...")
+    return n if n < 2 else fib(n - 2) + fib(n - 1)

python-314/jit_status.py

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+try:
+    from sys import _jit
+except ImportError:
+    print("Module sys._jit unavailable")
+else:
+    print("Python compiled with JIT support:", _jit.is_available())
+    print("JIT enabled for this process:", _jit.is_enabled())
+    print("JIT currently running:", _jit.is_active())

python-314/linked_list.py

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+# Uncomment for Python 3.14
+#
+# from dataclasses import dataclass
+# from typing import Any, Optional
+#
+#
+# @dataclass
+# class LinkedList:
+#     head: Node
+#
+#
+# @dataclass
+# class Node:
+#     value: Any
+#     next: Optional[Node] = None

python-314/repl/cli_script.py

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+import argparse
+
+parser = argparse.ArgumentParser("Command-Line Interface")
+parser.add_argument("path", help="Path to a file")
+parser.parse_args()

python-314/repl/pythonrc.py

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+# Set a custom color theme in Python 3.14
+try:
+    from _colorize import ANSIColors, default_theme, set_theme
+except ImportError:
+    pass
+else:
+    custom_theme = default_theme.copy_with(
+        syntax=default_theme.syntax.copy_with(
+            prompt=ANSIColors.GREY,
+            builtin="\x1b[38;2;189;147;249m",
+            comment="\x1b[38;2;98;114;164m",
+            definition="\x1b[38;2;139;233;253m",
+            keyword="\x1b[38;2;255;121;198m",
+            keyword_constant="\x1b[38;2;255;121;198m",
+            soft_keyword="\x1b[38;2;255;121;198m",
+            number="\x1b[38;2;189;147;249m",
+            op="\x1b[38;2;249;152;204m",
+            string="\x1b[38;2;241;250;140m",
+        ),
+        traceback=default_theme.traceback.copy_with(
+            error_highlight=ANSIColors.BOLD_YELLOW,
+            error_range=ANSIColors.YELLOW,
+            filename=ANSIColors.BACKGROUND_RED,
+            frame=ANSIColors.BACKGROUND_RED,
+            line_no=ANSIColors.BACKGROUND_RED,
+            message=ANSIColors.RED,
+            type=ANSIColors.BOLD_RED,
+        ),
+    )
+    set_theme(custom_theme)
+
+# Set a custom shell prompt
+import platform
+import sys
+
+version = platform.python_version()
+sys.ps1 = f"{version} \N{SNAKE} "
+sys.ps2 = "." * len(sys.ps1)

python-314/repl/test_dummy.py

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+import unittest
+
+
+class TestDummy(unittest.TestCase):
+    def test_dummy(self):
+        self.assertEqual(2 + 2, 22)

python-314/repl/todo.json

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+{"Shopping List": [{"title": "eggs", "details": null, "quantity": 12, "completed": true}, {"title": "bacon", "details": "smoke, 500g pack", "quantity": 1, "completed": false}, {"title": "ghee", "details": null, "quantity": 1, "completed": false}]}

python-314/subinterpreters.py

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+from concurrent.futures import (
+    InterpreterPoolExecutor,
+    ProcessPoolExecutor,
+    ThreadPoolExecutor,
+)
+from time import perf_counter
+
+MAX_VALUE = 35
+NUM_VALUES = 4
+NUM_WORKERS = 4
+
+
+def fib(n):
+    return n if n < 2 else fib(n - 2) + fib(n - 1)
+
+
+def compute(Pool):
+    t1 = perf_counter()
+    with Pool(max_workers=NUM_WORKERS) as pool:
+        list(pool.map(fib, [MAX_VALUE] * NUM_VALUES))
+    t2 = perf_counter()
+    print(f"{Pool.__name__}: {(t2 - t1):.2f}s")
+
+
+if __name__ == "__main__":
+    compute(InterpreterPoolExecutor)
+    compute(ProcessPoolExecutor)
+    compute(ThreadPoolExecutor)

python-314/tstrings.py

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+from dataclasses import dataclass
+from string.templatelib import Interpolation, Template, convert
+from typing import Any
+
+
+@dataclass(frozen=True)
+class SQLQuery:
+    statement: str
+    params: list[Any]
+
+    def __init__(self, template: Template) -> None:
+        items, params = [], []
+        for item in template:
+            match item:
+                case str():
+                    items.append(item)
+                case Interpolation(value, _, conversion, format_spec):
+                    converted = convert(value, conversion)
+                    if format_spec:
+                        converted = format(converted, format_spec)
+                    params.append(converted)
+                    items.append("?")
+        object.__setattr__(self, "statement", "".join(items))
+        object.__setattr__(self, "params", params)
+
+
+def find_users_query_v1(name: str) -> str:
+    """Return a SQL query to find users by name."""
+    return f"SELECT * FROM users WHERE name = '{name}'"
+
+
+# Uncomment for Python 3.14:
+#
+# def find_users_query_v2(name: str) -> Template:
+#     """Return a SQL query to find users by name."""
+#     return t"SELECT * FROM users WHERE name = '{name}'"
+#
+#
+# def find_users(name: str) -> SQLQuery:
+#     """Return a SQL query to find users by name."""
+#     return SQLQuery(t"SELECT * FROM users WHERE name = {name}")
+
+
+def render(template: Template) -> str:
+    return "".join(
+        f"{text}{value}"
+        for text, value in zip(template.strings, template.values)
+    )
+
+
+if __name__ == "__main__":
+    # Insecure f-strings
+    print(find_users_query_v1("' OR '1'='1"))
+
+    # Uncomment for Python 3.14:
+    #
+    # # More secure t-strings
+    # print(find_users_query_v2("' OR '1'='1"))
+    #
+    # # Insecure way of rendering t-strings into plain strings
+    # print(render(find_users_query_v2("' OR '1'='1")))
+    #
+    # # Rendering t-strings into an alternative representation
+    # print(find_users("' OR '1'='1"))

python-314/web_server.py

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+import os
+import sys
+from http.server import BaseHTTPRequestHandler, HTTPServer
+
+HOSTNAME = "localhost"
+PORT = 8000
+
+
+class Handler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        user_agent = self.headers.get("User-Agent")
+        self.send_response(200)
+        self.end_headers()
+        self.wfile.write(f"Hello, {user_agent}".encode())
+
+
+def main():
+    print(f"Starting the server on: http://{HOSTNAME}:{PORT}")
+    print("Run this command as a superuser to attach the debugger:")
+    print(f"{sys.executable} -m pdb -p {os.getpid()}")
+    HTTPServer((HOSTNAME, PORT), Handler).serve_forever()
+
+
+if __name__ == "__main__":
+    main()