handleSource method
Implementation
handleSource(String string, int errorLine) {
var lines = string.split('\n');
var lines2 = [];
int from = Math.max(errorLine - 6, 0);
int to = Math.min(errorLine + 6, lines.length);
for (var i = 0; i < lines.length; i++) {
lines[i] = "${(i + 1)}: ${lines[i]}";
}
for (var i = from; i < to; i++) {
lines2.add("${(i + 1)}: ${lines[i]}");
}
return lines2.join('\n');
}