in terminal.go [591:605]
func (t *Terminal) addKeyToLine(key rune) {
if len(t.line) == cap(t.line) {
newLine := make([]rune, len(t.line), 2*(1+len(t.line)))
copy(newLine, t.line)
t.line = newLine
}
t.line = t.line[:len(t.line)+1]
copy(t.line[t.pos+1:], t.line[t.pos:])
t.line[t.pos] = key
if t.echo {
t.writeLine(t.line[t.pos:])
}
t.pos++
t.moveCursorToPos(t.pos)
}