Insert characters

Before inserting a character, we check if we are in a new row, if so, we insert the row in the buffer. After that, we can just insert the character and move forward. We wrote already our insertRow() function, so there's nothing to add (for now).

///////////////////////////////////////////////////////////////////////////////
//
//                              In-row operations
//
///////////////////////////////////////////////////////////////////////////////

/// Insert a character at current cursor position. Handle textwidth.
fn insertChar(e: *Editor, c: u8) !void {
    const V = &e.view;

    // last row, insert a new row before inserting the character
    if (V.cy == e.buffer.rows.items.len) {
        try e.insertRow(e.buffer.rows.items.len, "");
    }

    // insert the character and move the cursor forward
    try e.rowInsertChar(V.cy, V.cx, c);
    V.cx += 1;
}

rowInsertChar()

This will perform the actual character insertion in the row.chars ArrayList, update the rendered row, and set the modified flag.

/// Insert character `c` in the row with index `ix`, at column `at`.
fn rowInsertChar(e: *Editor, ix: usize, at: usize, c: u8) !void {
    try e.rowAt(ix).chars.insert(e.buffer.alc, at, c);
    try e.updateRow(ix);
    e.buffer.dirty = true;
}