indexOf method
Returns the position of the first match of pattern in this view,
starting the search at start.
Implementation
int indexOf(String pattern, [int start = 0]) {
if (start < 0 || start > length) return -1;
if (pattern.isEmpty) return start;
if (pattern.length > length - start) return -1;
for (int i = start; i <= length - pattern.length; i++) {
bool match = true;
for (int j = 0; j < pattern.length; j++) {
if (_string[_start + i + j] != pattern[j]) {
match = false;
break;
}
}
if (match) return i;
}
return -1;
}