indentWidth function
Number of leading-indent columns (space = 1, tab = 4).
Implementation
int indentWidth(String line) {
var w = 0;
for (var i = 0; i < line.length; i++) {
final c = line.codeUnitAt(i);
if (c == _space) {
w += 1;
} else if (c == _tab) {
w += 4;
} else {
break;
}
}
return w;
}