Regular Expressions 101

1st Alternative(?>(break;|:|{)[\r\n\s]*case)

Atomic Group(?>(break;|:|{)[\r\n\s]*case)

Group 1(break;|:|{)

1st Alternativebreak;

break;the literal text break; (case sensitive)

2nd Alternative:

:the literal : (58₁₀ / 72₈ / 3A₁₆)

3rd Alternative{

{the literal { (123₁₀ / 173₈ / 7B₁₆)

Character Class[\r\n\s]*

*matches any number of characters from the set below:

\ra carriage return (ASCII 13)

\na line-feed (newline) character (ASCII 10)

\sany whitespace character

casethe literal text case (case sensitive)

2nd Alternative (?<fallthrough>case)

Group fallthrough(?<fallthrough>case)

casethe literal text case (case sensitive)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?>(break;|:|{)[\r\n\s]*case) | (?<fallthrough>case)

New

switch (item) {
    case 1:
    case 2:
       doStuff();
       break;
    case 3:
    case 4:
       doOtherStuff();
       break;
}

switch (item) {
    case 1:
    case 2:
       doStuff(); // should detect this
    case 3:
    case 4:
       doOtherStuff();
       break;
}

Regular Expression

Extraction