regex101: PCRE (Legacy) Match Workspace

Group header_all(?<header_all> (?<header_content>.+) # Header content [ \t]* (?<!\\) # Making sure it is not escaped \{ [[:blank:]\h]* # Possibly with some spaces (?<header_attr>.+?) # and attributes instead braces [[:blank:]\h]* \} [ \t]* # Possibly followed by spaces or tabs \n # With then a new line (?<!\\) # Making sure this is not escaped (?<header_type>[\=|\-]+) # Multiple = or - [ \t]* # Possibly followed by spaces or tabs \n # Terminated by a new line )

Group header_content(?<header_content>.+)

.+any character (except for line terminators), repeated at least once

Comment: Header content

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Negative Lookbehind(?<!\\)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

Comment: Making sure it is not escaped

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Character Class[[:blank:]\h]*

*matches any number of characters from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

\hany horizontal whitespace character

Comment: Possibly with some spaces

Group header_attr(?<header_attr>.+?)

.+?any character (except for line terminators), repeated at least once

Comment: and attributes instead braces

Character Class[[:blank:]\h]*

*matches any number of characters from the set below:

[:blank:]a whitespace character, excluding line breaks [ \t]

\hany horizontal whitespace character

\}the literal } (125₁₀ / 175₈ / 7D₁₆)

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Comment: Possibly followed by spaces or tabs

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

Comment: With then a new line

Negative Lookbehind(?<!\\)

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

Comment: Making sure this is not escaped

Group header_type(?<header_type>[\=|\-]+)

Character Class[\=|\-]+

+matches at least one character from the set below:

\=the literal = (61₁₀ / 75₈ / 3D₁₆)

|the literal | (124₁₀ / 174₈ / 7C₁₆)

\-the literal - (45₁₀ / 55₈ / 2D₁₆)

Comment: Multiple = or -

Character Class[ \t]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\ta tab character (ASCII 9)

Comment: Possibly followed by spaces or tabs

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

Comment: Terminated by a new line

Global pattern flags

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

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

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

25 tokens

Regular Expression

(?<header_all>
    (?<header_content>.+)       # Header content
    [ \t]*
    (?<!\\)                     # Making sure it is not escaped
    \{
        [[:blank:]\h]*          # Possibly with some spaces
        (?<header_attr>.+?)     # and attributes instead braces
        [[:blank:]\h]*
    \}
    [ \t]*                      # Possibly followed by spaces or tabs
    \n                          # With then a new line
    (?<!\\)                     # Making sure this is not escaped
    (?<header_type>[\=|\-]+)    # Multiple = or -
    [ \t]*                      # Possibly followed by spaces or tabs
    \n                          # Terminated by a new line
)

New

Header  {#id1}
======

Header  { #id2}
------

Header  {.cl}
======

Header  { .cl}
------

Header  {.cl.class}
======

Header  { .cl .class}
------

Header  {#id5.cl.class}
======

Header  { #id6 .cl .class}
------

Substitution

Header  {#id1}
======

Header  { #id2}
------

Header  {.cl}
======

Header  { .cl}
------

Header  {.cl.class}
======

Header  { .cl .class}
------

Header  {#id5.cl.class}
======

Header  { #id6 .cl .class}
------