text editor sample

pragma(lib, "user32.lib");
pragma(lib, "gdi32.lib");

import core.sys.windows.windows;
import std.string;
import std.conv;

__gshared HWND hEdit;

enum ID_EDIT = 101;

extern(Windows) nothrow
LRESULT WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    switch (msg)
    {
        case WM_CREATE:
        {
            hEdit = CreateWindowEx(
                0,
                "EDIT",
                null,
                WS_CHILD | WS_VISIBLE |
                WS_VSCROLL | WS_HSCROLL |
                ES_MULTILINE | ES_AUTOVSCROLL | ES_AUTOHSCROLL,
                0, 0, 500, 400,
                hwnd,
                cast(HMENU) ID_EDIT,
                GetModuleHandle(null),
                null
            );
            return 0;
        }

        case WM_SIZE:
        {
            int width = LOWORD(lParam);
            int height = HIWORD(lParam);

            MoveWindow(hEdit, 0, 0, width, height, TRUE);
            return 0;
        }

        case WM_DESTROY:
        {
            PostQuitMessage(0);
            return 0;
        }

        default:
            return DefWindowProc(hwnd, msg, wParam, lParam);
    }
}

void main()
{
    HINSTANCE hInstance = GetModuleHandle(null);

    WNDCLASS wc;
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = &WndProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(null, IDC_ARROW);
    wc.hbrBackground = cast(HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszClassName = "DTextEditor";

    RegisterClass(&wc);

    HWND hwnd = CreateWindowEx(
        0,
        "DTextEditor",
        "Mini Text Editor - D + Win32",
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        800,
        600,
        null,
        null,
        hInstance,
        null
    );

    ShowWindow(hwnd, SW_SHOW);
    UpdateWindow(hwnd);

    MSG msg;
    while (GetMessage(&msg, null, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}