Inserting a row

If you remember, our Row type had two arrays:

/// The ArrayList with the actual row characters
chars: t.Chars,

/// Array with the visual representation of the row
render: []u8,

where Chars is actually a std.ArrayList(u8), which we'll be using a lot.

In our insertRow() function, what we'll do is:

• initialize a new Row
• copy the line into row.chars
• insert the row in Buffer.rows

Finally we'll update the row, and set the dirty flag.

///////////////////////////////////////////////////////////////////////////////
//
//                              Row operations
//
///////////////////////////////////////////////////////////////////////////////

/// Insert a row at index `ix` with content `line`, then update it.
fn insertRow(e: *Editor, ix: usize, line: []const u8) !void {
    const B = &e.buffer;

    var row = try t.Row.init(B.alc);
    try row.chars.appendSlice(B.alc, line);

    try B.rows.insert(B.alc, ix, row);

    try e.updateRow(ix);
    B.dirty = true;
}

We set the dirty flag because the same function will be used while modifying the buffer, but for now we're just reading the file. This flag will be reset in openFile().

Add this at the bottom of openFile():

    else |err| switch (err) {
        error.FileNotFound => {}, // new unsaved file
        else => return err,
    }

    B.dirty = false;

}