The message area

For the message area we'll need more Editor fields:

/// String to be printed in the message area (can be a prompt)
status_msg: t.Chars,

/// Controls the visibility of the status message
status_msg_time: i64,

Also add these constants:

const time = std.time.timestamp;
const time_ms = std.time.milliTimestamp;

const initial_msg_size = 80;

Add to init():

        .status_msg = try t.Chars.initCapacity(allocator, initial_msg_size),
        .status_msg_time = 0,

and to deinit() (always deinitialize ArrayLists or they will leak):

    e.status_msg.deinit(e.alc);

Uncomment the line in refreshScreen() where we draw the message area.

    try e.drawRows();
    try e.drawStatusline();

    // try e.drawMessageBar();

    try e.drawMessageBar();

The drawMessageBar() function

I put this below finalizeStatusline():

/// Append the message bar to the surface.
fn drawMessageBar(e: *Editor) !void {
    try e.toSurface(ansi.ClearLine);

    var msglen = e.status_msg.items.len;
    if (msglen > e.screen.cols) {
        msglen = e.screen.cols;
    }
    if (msglen > 0 and time() - e.status_msg_time < 5) {
        try e.toSurface(e.status_msg.items[0 .. msglen]);
    }
}

As you can see, it's pretty simple. We clear the line, then if there's a message to be printed, we append it to the surface.

We have also some sort of timer: it's not a real timer in the sense that there's not an async timer that runs independently from the main thread. Remember that the screen is redrawn in the event loop, whose iterations are controlled by the processKeypress() function, since it's that function that halts the loop while waiting for new keys pressed by the user. So what this "timer" does, is to check if 5 seconds have passed since the last redraw, then it will append the message to the surface if it didn't, otherwise it will not append anything, and the message won't be printed.

It will be the function which sets a status message that will update status_msg_time, but we don't have a way to set a status message yet.