(8) Regular Expression backtracking and non-backtracking

Use "(?> ...)" Method. Due to the greedy nature of the Regular Expression Engine, in some cases, it will be traced back for matching. See the following example:

Code
String x = "Live for nothing, die for something ";
RegEx R1 = new RegEx (@ ". * thing ,");
If (r1.ismatch (x ))
{
Console. writeline ("Match:" + r1.match (x). Value); // output: Live for nothing,
}
RegEx r2 = new RegEx (@ "(?>. *) Thing ,");
If (r2.ismatch (x) // Mismatch
{
Console. writeline ("Match:" + r2.match (x). value );
}
// In R1, ". * "because of its greedy feature, it will always match the end of the string, and then match" thing ", but fails when", ". In this case, the engine will trace back and,.
In R2, the entire expression fails to be matched due to forced non-backtracking.