regex101: PCRE (Legacy) Match Workspace

Definition Group(?(DEFINE) (?<block> \{ # Match opening brace (?: # Start non-capturing group [^{}]++ # Match non-brace characters without backtracking | # or (?&block) # Recursively match the last captured group )* # Match 0 or more times \} # Match closing brace ) )

Group block(?<block> \{ # Match opening brace (?: # Start non-capturing group [^{}]++ # Match non-brace characters without backtracking | # or (?&block) # Recursively match the last captured group )* # Match 0 or more times \} # Match closing brace )

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Comment: Match opening brace

Non-Capturing Group(?: # Start non-capturing group [^{}]++ # Match non-brace characters without backtracking | # or (?&block) # Recursively match the last captured group )*

*repeats the group contents below any number of times:

1st Alternative # Start non-capturing group [^{}]++ # Match non-brace characters without backtracking

Comment: Start non-capturing group

Negated Character Class[^{}]++

++matches at least one character outside the set below:

{the literal { (123₁₀ / 173₈ / 7B₁₆)

}the literal } (125₁₀ / 175₈ / 7D₁₆)

Comment: Match non-brace characters without backtracking

2nd Alternative # or (?&block) # Recursively match the last captured group

Comment: or

(?&block)calls group block as a subroutine

Comment: Recursively match the last captured group

Comment: Match 0 or more times

\}the literal } (125₁₀ / 175₈ / 7D₁₆)

Comment: Match closing brace

Group 2(.+?)

.+?any character, repeated at least once

(?&block)calls group block as a subroutine

Group 3(.+)

.+any character, repeated at least once

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

s modifier: single line. Allows a dot to match line terminators

Search reference

Regular Expression

(?(DEFINE)
    (?<block>
        \{                # Match opening brace
            (?:           # Start non-capturing group
                [^{}]++   #     Match non-brace characters without backtracking
                |         #     or
                (?&block) #     Recursively match the last captured group
            )*            # Match 0 or more times
        \}                # Match closing brace
    )
)(.+?)(?&block)(.+)

New

use strict;
use warnings;

my $text = << "END";
int max(int x, int y)
{
    if (x > y)
    {
        return x;
    }
    else
    {
        return y;
    }
}
// something here

Regular Expressions 101

Regular Expression

Extraction