Add 3.12 release video

Author: jamesmurphy-mc

README.md

@@ -12,6 +12,7 @@ James and his team are available for consulting, contracting, code reviews, and
 
 | N   | Code | Video | 
 |-----| --- |--- |
+| 130 | [src](videos/130_python_312_release) | [Python 3.12 is HERE!](https://youtu.be/8l4UWz48Elc) |
 | 129 | [src](videos/129_lambda_in_a_loop_is_a_code_smell) | [Lambda in a Loop is a Code Smell](https://youtu.be/fZE6ZWde-Os) |
 | 128 | [src](videos/128_id_mapping) | [A forbidden Python technique to put ANYTHING in a dict or set.](https://youtu.be/NpdNDTncxwA) |
 | 127 | [src](videos/127_accidentally_quadratic_unique_sum) | [Don't make this big O mistake!](https://youtu.be/PXWL_Xzyrp4) |

videos/130_python_312_release/buffer-defs.c

@@ -0,0 +1,20 @@
+// From cpython/Include/pybuffer.h
+
+typedef struct {
+    void *buf;
+    PyObject *obj;        
+    Py_ssize_t len;
+    Py_ssize_t itemsize;
+    int readonly;
+    int ndim;
+    char *format;
+    Py_ssize_t *shape;
+    Py_ssize_t *strides;
+    Py_ssize_t *suboffsets;
+    void *internal;
+} Py_buffer;
+
+typedef int (*getbufferproc)(PyObject *, Py_buffer *, int);
+typedef void (*releasebufferproc)(PyObject *, Py_buffer *);
+
+

videos/130_python_312_release/buffer_demo.py

@@ -0,0 +1,41 @@
+# Example from PEP 688
+
+import inspect
+
+# Implements __buffer__, __release_buffer__
+class MyBuffer:
+    def __init__(self, data: bytes):
+        self.data = bytearray(data)
+        self.view = None
+
+    def __buffer__(self, flags: int) -> memoryview:
+        if flags != inspect.BufferFlags.FULL_RO:
+            raise TypeError("Only BufferFlags.FULL_RO supported")
+        if self.view is not None:
+            raise RuntimeError("Buffer already held")
+        self.view = memoryview(self.data)
+        return self.view
+
+    def __release_buffer__(self, view: memoryview) -> None:
+        assert self.view is view  # guaranteed to be true
+        self.view.release()
+        self.view = None
+
+    def extend(self, b: bytes) -> None:
+        if self.view is not None:
+            raise RuntimeError("Cannot extend held buffer")
+        self.data.extend(b)
+
+def main():
+    buffer = MyBuffer(b"capybara")
+
+    # __buffer__ called here in memoryview:
+    #    vvvvvvvvvvvvvvvvvv
+    with memoryview(buffer) as view: 
+        view[0] = ord("C")
+        # __release_buffer__ called exiting with block
+
+    # buffer now contains b"Capybara"
+
+if __name__ == "__main__":
+    main()

videos/130_python_312_release/itertools_batched.py

@@ -0,0 +1,16 @@
+import itertools
+
+
+def print_batches():
+    data = [1, 2, 3, 4, 5, 6, 7, 8]
+    for batch in itertools.batched(data, 3):
+        print(batch)
+    # (1, 2, 3)
+    # (4, 5, 6)
+    # (7, 8)
+
+def main():
+    print_batches()
+
+if __name__ == '__main__':
+    main()

videos/130_python_312_release/monitoring_demo.py

@@ -0,0 +1,24 @@
+import sys
+
+def my_trace_call(code, instruction_offset, call, arg0):
+    print("Event: call")
+
+def my_trace_line(code, line_number):
+    print("Event: line")
+
+def setup_monitoring():
+    mo = sys.monitoring
+    events = mo.events
+    mo.use_tool_id(0, "my_debugger")
+    mo.set_events(0, events.CALL | events.LINE)
+    mo.register_callback(0, events.CALL, my_trace_call)
+    mo.register_callback(0, events.LINE, my_trace_line)
+
+def main():
+    for x in range(5):
+        print(x)
+
+if __name__ == "__main__":
+    setup_monitoring()
+    main()
+

videos/130_python_312_release/none_refcount_demo.py

@@ -0,0 +1,9 @@
+import sys
+
+def main():
+    count = sys.getrefcount(None)
+    print(f"0b{count:b}")
+
+
+if __name__ == "__main__":
+    main()

videos/130_python_312_release/refcount_demo.py

@@ -0,0 +1,13 @@
+import sys
+
+def main():
+    my_list = [1, 2, 3]
+    print(sys.getrefcount(my_list)) # 2
+    use_list(my_list)
+
+def use_list(lst):
+    print(sys.getrefcount(lst)) # 3
+
+
+if __name__ == "__main__":
+    main()

videos/130_python_312_release/settrace_demo.py

@@ -0,0 +1,14 @@
+import sys
+
+def my_trace(frame, event, arg):
+    print(f"Event: {event}")
+    return my_trace
+
+def main():
+    for x in range(5):
+        print(x)
+
+if __name__ == "__main__":
+    sys.settrace(my_trace)
+    main()
+

videos/130_python_312_release/slow_debug.py

@@ -0,0 +1,146 @@
+# -*- coding: utf-8 -*-
+import collections
+import itertools
+import os
+import pathlib
+import sys
+import time
+
+import numpy as np
+
+# For Linux/Wayland users.
+if os.getenv("XDG_SESSION_TYPE") == "wayland":
+    os.environ["XDG_SESSION_TYPE"] = "x11"
+
+import glfw
+import OpenGL.GL as gl
+import imgui
+from imgui.integrations.glfw import GlfwRenderer
+
+DRIFT_SPEED = 100
+TAIL_LENGTH = 1000
+
+frame_time = 0.0
+
+
+def tick():
+    global frame_time
+    frame_time = time.perf_counter()
+
+
+bm = collections.deque([np.array([0., 0.])] * 10, maxlen=TAIL_LENGTH)
+
+IS_DEBUG = (sys.gettrace() is not None)
+
+
+def frame_commands():
+    last_time = frame_time
+    tick()
+    curr_time = frame_time
+    dt = curr_time - last_time
+    try:
+        fps = int(1 / dt)
+    except ZeroDivisionError:
+        fps = 0
+
+    io = imgui.get_io()
+
+    if io.key_ctrl and io.keys_down[glfw.KEY_Q]:
+        sys.exit(0)
+
+    with imgui.begin_main_menu_bar() as main_menu_bar:
+        if main_menu_bar.opened:
+            with imgui.begin_menu("File", True) as file_menu:
+                if file_menu.opened:
+                    clicked_quit, selected_quit = imgui.menu_item("Quit", "Ctrl+Q")
+                    if clicked_quit:
+                        sys.exit(0)
+
+    with imgui.begin("FPS"):
+        imgui.text(f"Debug: ")
+        imgui.same_line()
+        if IS_DEBUG:
+            imgui.text_colored("ON", 0., 1., 0.)
+        else:
+            imgui.text_colored("OFF", 1., 0., 0.)
+        imgui.text(f"FPS: {fps}")
+
+    scale = np.sqrt(dt) * 200
+    dbm = np.random.multivariate_normal(mean=(0.0, 0.0), cov=scale * np.eye(2))
+    next_bm = bm[len(bm) - 1] + dbm
+    next_bm = np.maximum(next_bm, 0.0)
+    next_bm = np.minimum(next_bm, np.array(glfw.get_window_size(glfw.get_current_context())))
+    bm.append(next_bm)
+    if tuple(io.mouse_pos) != (-1, -1):
+        drift = (np.array(io.mouse_pos) - next_bm) / DRIFT_SPEED
+        next_bm += drift
+    draw_list = imgui.get_overlay_draw_list()
+    for idx, ((x1, y1), (x2, y2)) in enumerate(itertools.pairwise(bm)):
+        color = imgui.get_color_u32_rgba(1., 1., 1., idx / (len(bm) - 1))
+        draw_list.add_line(x1, y1, x2, y2, color, thickness=1.0)
+
+
+def render_frame(impl, window, font):
+    glfw.poll_events()
+    impl.process_inputs()
+    imgui.new_frame()
+
+    gl.glClearColor(0.1, 0.1, 0.1, 1)
+    gl.glClear(gl.GL_COLOR_BUFFER_BIT)
+
+    imgui.push_font(font)
+    frame_commands()
+    imgui.pop_font()
+
+    imgui.render()
+    impl.render(imgui.get_draw_data())
+    glfw.swap_buffers(window)
+
+
+def impl_glfw_init():
+    width, height = 600, 600
+    window_name = "Brownian motion demo"
+
+    if not glfw.init():
+        print("Could not initialize OpenGL context")
+        sys.exit(1)
+
+    glfw.window_hint(glfw.CONTEXT_VERSION_MAJOR, 4)
+    glfw.window_hint(glfw.CONTEXT_VERSION_MINOR, 3)
+    glfw.window_hint(glfw.OPENGL_PROFILE, glfw.OPENGL_CORE_PROFILE)
+    glfw.window_hint(glfw.OPENGL_FORWARD_COMPAT, gl.GL_TRUE)
+
+    window = glfw.create_window(int(width), int(height), window_name, None, None)
+    glfw.make_context_current(window)
+    glfw.swap_interval(0)
+
+    if not window:
+        glfw.terminate()
+        print("Could not initialize Window")
+        sys.exit(1)
+
+    return window
+
+
+def main():
+    imgui.create_context()
+    window = impl_glfw_init()
+
+    impl = GlfwRenderer(window)
+
+    font_path = pathlib.Path(__file__).with_name("Montserrat-ExtraBold.ttf")
+    try:
+        font = imgui.get_io().fonts.add_font_from_file_ttf(str(font_path), 80)
+    except imgui.ImGuiError:
+        font = imgui.get_io().fonts.add_font_default()
+    impl.refresh_font_texture()
+
+    while not glfw.window_should_close(window):
+        render_frame(impl, window, font)
+
+    impl.shutdown()
+    glfw.terminate()
+
+
+if __name__ == "__main__":
+    main()