regex101: PCRE (Legacy) Match Workspace

Group footnote_all(?<footnote_all> ^[ ]{0,3} \[\^(?<footnote_id>.+?)\][ ]?: # footnote id [ ]* \n? # maybe *one* newline (?<footnote_text> # footnote text (no blank lines allowed) (?: .+ # actual text | \n # newlines but (?!\[.+?\][ ]?:\s) # negative lookahead for footnote or link definition marker. (?!\n+[ ]{0,3}\S) # ensure line is not blank and followed # by non-indented content )* ) )

^start of line

Character Class[ ]{0,3}

{0,3}matches between 0 and 3 characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

\^the literal ^ (94₁₀ / 136₈ / 5E₁₆)

Group footnote_id(?<footnote_id>.+?)

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

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Character Class[ ]?

?matches at most one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

: the literal text :

Comment: footnote id

Character Class[ ]*

*matches any number of characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\n?optionally matches a line-feed (newline) character (ASCII 10)

Comment: maybe *one* newline

Group footnote_text(?<footnote_text> # footnote text (no blank lines allowed) (?: .+ # actual text | \n # newlines but (?!\[.+?\][ ]?:\s) # negative lookahead for footnote or link definition marker. (?!\n+[ ]{0,3}\S) # ensure line is not blank and followed # by non-indented content )* )

Comment: footnote text (no blank lines allowed)

Non-Capturing Group(?: .+ # actual text | \n # newlines but (?!\[.+?\][ ]?:\s) # negative lookahead for footnote or link definition marker. (?!\n+[ ]{0,3}\S) # ensure line is not blank and followed # by non-indented content )*

*repeats the group contents below any number of times:

1st Alternative .+ # actual text

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

Comment: actual text

2nd Alternative \n # newlines but (?!\[.+?\][ ]?:\s) # negative lookahead for footnote or link definition marker. (?!\n+[ ]{0,3}\S) # ensure line is not blank and followed # by non-indented content

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

Comment: newlines but

Negative Lookahead(?!\[.+?\][ ]?:\s)

\[the literal [ (91₁₀ / 133₈ / 5B₁₆)

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

\]the literal ] (93₁₀ / 135₈ / 5D₁₆)

Character Class[ ]?

?matches at most one character from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\sany whitespace character

Comment: negative lookahead for footnote or link definition marker.

Negative Lookahead(?!\n+[ ]{0,3}\S)

\n+a line-feed (newline) character (ASCII 10), repeated at least once

Character Class[ ]{0,3}

{0,3}matches between 0 and 3 characters from the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

\Sany non-whitespace character

Comment: ensure line is not blank and followed

Comment: by non-indented content

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

(?<footnote_all>
    ^[ ]{0,3}
    \[\^(?<footnote_id>.+?)\][ ]?:      # footnote id
    [ ]*
    \n?					                # maybe *one* newline
    (?<footnote_text>					# footnote text (no blank lines allowed)
        (?:
            .+				            # actual text
            |
            \n				            # newlines but
            (?!\[.+?\][ ]?:\s)          # negative lookahead for footnote or link definition marker.
            (?!\n+[ ]{0,3}\S)           # ensure line is not blank and followed
                                        # by non-indented content
        )*
    )
)

New

This is the first paragraph.[^first]

[^first]:  This is the first note.

* List item one.[^second]
* List item two.[^third]

[^third]: This is the third note, defined out of order.
[^second]: This is the second note.
[^fourth]: This is the fourth note.

# Header[^fourth]

Some paragraph with a footnote[^1], and another[^2].

[^1]: Content for fifth footnote.
[^2]: Content for sixth footnote spaning on 
    three lines, with some span-level markup like
    _emphasis_, a [link][].

[link]: http://michelf.ca/

Another paragraph with a named footnote[^fn-name].

[^fn-name]:
    Footnote beginning on the line next to the marker.

[^block]:
	Paragraph.
	
	*   List item
	
	> Blockquote
	
	    Code block

[^image-mixed]: Footnote Content
[img7]: images/MGR-1830-travel.jpeg "Travel Speeds in 1830"