static bool TryExpandSelection(ref int begin, ref int end, StringSlice line, Func <StringSlice, bool, StringSlice?> testSubstr)
{
int begin2 = begin;
int end2 = end;
while (begin2 > 0 && testSubstr(line.Slice(begin2 - 1, end2), true) != null)
{
--begin2;
}
while (end2 <= line.Length - 1 && testSubstr(line.Slice(begin2, end2 + 1), true) != null)
{
++end2;
}
var finalStr = testSubstr(line.Slice(begin2, end2), false);
if (finalStr == null)
{
return(false);
}
begin = finalStr.Value.StartIndex - line.StartIndex;
end = finalStr.Value.EndIndex - line.StartIndex;
return(true);
}