Run this with `cargo test --features gen-tests suite::footnotes`.
Parts of this test case are based on
<https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702>.
Other parts were based on trial-and-error with GitHub's issue comment preview.
This spec describes nearly identical *parsing* to GFM, but not identical *rendering*. The HTML
outputting module may be extended with features such as backreferences, but these are not built
into the parser, and are unrelated to the syntax in any case. Alternative footnote rendering
styles can be found in `/examples/footnote-rewrite.rs`.
```````````````````````````````` example
Lorem ipsum.[^a] [^missing]
[^a]: Cool.
.
<p>Lorem ipsum.<sup><a href="#user-content-fn-a" id="user-content-fnref-a" data-footnote-ref aria-describedby="footnote-label">1</a></sup> [^missing]</p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-a">
<p>Cool. <a href="#user-content-fnref-a" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Footnotes can be used inside blockquotes:
```````````````````````````````` example
> This is the song that never ends.\
> Yes it goes on and on my friends.[^lambchops]
>
> [^lambchops]: <https://www.youtube.com/watch?v=0U2zJOryHKQ>
.
<blockquote>
<p>This is the song that never ends.<br>
Yes it goes on and on my friends.<sup><a href="#user-content-fn-lambchops" id="user-content-fnref-lambchops" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
</blockquote>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-lambchops">
<p><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">https://www.youtube.com/watch?v=0U2zJOryHKQ</a> <a href="#user-content-fnref-lambchops" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Footnotes can be complex block structures, but their contents must be indented first!
Without four spaces of indentation, no nesting:
```````````````````````````````` example
Songs that simply loop are a popular way to annoy people. [^examples]
[^examples]:
* [The song that never ends](https://www.youtube.com/watch?v=0U2zJOryHKQ)
* [I know a song that gets on everybody's nerves](https://www.youtube.com/watch?v=TehWI09qxls)
* [Ninety-nine bottles of beer on the wall](https://www.youtube.com/watch?v=qVjCag8XoHQ)
.
<p>Songs that simply loop are a popular way to annoy people. <sup><a href="#user-content-fn-examples" id="user-content-fnref-examples" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
<ul>
<li><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">The song that never ends</a></li>
<li><a href="https://www.youtube.com/watch?v=TehWI09qxls">I know a song that gets on everybody's nerves</a></li>
<li><a href="https://www.youtube.com/watch?v=qVjCag8XoHQ">Ninety-nine bottles of beer on the wall</a></li>
</ul>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-examples">
<a href="#user-content-fnref-examples" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a>
</li>
</ol>
</section>
````````````````````````````````
Yes, nesting:
```````````````````````````````` example
Songs that simply loop are a popular way to annoy people. [^examples]
[^examples]:
* [The song that never ends](https://www.youtube.com/watch?v=0U2zJOryHKQ)
* [I know a song that gets on everybody's nerves](https://www.youtube.com/watch?v=TehWI09qxls)
* [Ninety-nine bottles of beer on the wall](https://www.youtube.com/watch?v=qVjCag8XoHQ)
.
<p>Songs that simply loop are a popular way to annoy people. <sup><a href="#user-content-fn-examples" id="user-content-fnref-examples" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-examples">
<ul>
<li><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">The song that never ends</a></li>
<li><a href="https://www.youtube.com/watch?v=TehWI09qxls">I know a song that gets on everybody's nerves</a></li>
<li><a href="https://www.youtube.com/watch?v=qVjCag8XoHQ">Ninety-nine bottles of beer on the wall</a></li>
</ul>
<a href="#user-content-fnref-examples" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a>
</li>
</ol>
</section>
````````````````````````````````
How this works with indented code blocks, blockquotes:
```````````````````````````````` example
[^not-code] [^code] [^quote] [^not-quote] [^indented-quote]
[^not-code]: not code
[^code]:
code
[^quote]: > quote
[^not-quote]:
> external quote
[^indented-quote]:
> indented quote
.
<p><sup><a href="#user-content-fn-not-code" id="user-content-fnref-not-code" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-code" id="user-content-fnref-code" data-footnote-ref aria-describedby="footnote-label">2</a></sup> <sup><a href="#user-content-fn-quote" id="user-content-fnref-quote" data-footnote-ref aria-describedby="footnote-label">3</a></sup> <sup><a href="#user-content-fn-not-quote" id="user-content-fnref-not-quote" data-footnote-ref aria-describedby="footnote-label">4</a></sup> <sup><a href="#user-content-fn-indented-quote" id="user-content-fnref-indented-quote" data-footnote-ref aria-describedby="footnote-label">5</a></sup></p>
<blockquote>
<p>external quote</p>
</blockquote>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-not-code">
<p>not code <a href="#user-content-fnref-not-code" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-code">
<pre><code>code
</code></pre>
<a href="#user-content-fnref-code" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-quote">
<blockquote>
<p>quote</p>
</blockquote>
<a href="#user-content-fnref-quote" data-footnote-backref="" aria-label="Back to reference 3" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-not-quote">
<a href="#user-content-fnref-not-quote" data-footnote-backref="" aria-label="Back to reference 4" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-indented-quote">
<blockquote>
<p>indented quote</p>
</blockquote>
<a href="#user-content-fnref-indented-quote" data-footnote-backref="" aria-label="Back to reference 5" class="data-footnote-backref">↩</a>
</li>
</ol>
</section>
````````````````````````````````
Line breaks in paragraphs, however, are okay. Note that GitHub *comments* have hard line breaks without escapes, while *Gists* don't.
To see compatible rendering with the examples in this file, try the code in a GitHub Gist file with a `.md` extension.
```````````````````````````````` example
[^ab] [^cd]
[^ab]: a
b
[^cd]: c\
d
.
<p><sup><a href="#user-content-fn-ab" id="user-content-fnref-ab" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-cd" id="user-content-fnref-cd" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-ab">
<p>a
b <a href="#user-content-fnref-ab" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-cd">
<p>c<br>
d <a href="#user-content-fnref-cd" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Footnotes can even have multiple paragraphs. You need to indent, though.
```````````````````````````````` example
[^lorem]: If heaven ever wishes to grant me a boon, it will be a total effacing of the results of a mere chance which fixed my eye on a certain stray piece of shelf-paper. It was nothing on which I would naturally have stumbled in the course of my daily round, for it was an old number of an Australian journal, the Sydney Bulletin for April 18, 1925. It had escaped even the cutting bureau which had at the time of its issuance been avidly collecting material for my uncle's research.
I had largely given over my inquiries into what Professor Angell called the "Cthulhu Cult", and was visiting a learned friend in Paterson, New Jersey; the curator of a local museum and a mineralogist of note. Examining one day the reserve specimens roughly set on the storage shelves in a rear room of the museum, my eye was caught by an odd picture in one of the old papers spread beneath the stones. It was the Sydney Bulletin I have mentioned, for my friend had wide affiliations in all conceivable foreign parts; and the picture was a half-tone cut of a hideous stone image almost identical with that which Legrasse had found in the swamp.
[^ipsum]: If heaven ever wishes to grant me a boon, it will be a total effacing of the results of a mere chance which fixed my eye on a certain stray piece of shelf-paper. It was nothing on which I would naturally have stumbled in the course of my daily round, for it was an old number of an Australian journal, the Sydney Bulletin for April 18, 1925. It had escaped even the cutting bureau which had at the time of its issuance been avidly collecting material for my uncle's research.
I had largely given over my inquiries into what Professor Angell called the "Cthulhu Cult", and was visiting a learned friend in Paterson, New Jersey; the curator of a local museum and a mineralogist of note. Examining one day the reserve specimens roughly set on the storage shelves in a rear room of the museum, my eye was caught by an odd picture in one of the old papers spread beneath the stones. It was the Sydney Bulletin I have mentioned, for my friend had wide affiliations in all conceivable foreign parts; and the picture was a half-tone cut of a hideous stone image almost identical with that which Legrasse had found in the swamp.
.
<p>I had largely given over my inquiries into what Professor Angell called the "Cthulhu Cult", and was visiting a learned friend in Paterson, New Jersey; the curator of a local museum and a mineralogist of note. Examining one day the reserve specimens roughly set on the storage shelves in a rear room of the museum, my eye was caught by an odd picture in one of the old papers spread beneath the stones. It was the Sydney Bulletin I have mentioned, for my friend had wide affiliations in all conceivable foreign parts; and the picture was a half-tone cut of a hideous stone image almost identical with that which Legrasse had found in the swamp.</p>
````````````````````````````````
A footnote will end on a single line break if the following paragraph isn't indented. Note that
this behavior changed in version 0.1.0, to become more like hoedown. See issue #21.
```````````````````````````````` example
[^ipsum]: How much wood would a woodchuck chuck.
If a woodchuck could chuck wood.
# Forms of entertainment that aren't childish
.
<p>If a woodchuck could chuck wood.</p>
<h1>Forms of entertainment that aren't childish</h1>
````````````````````````````````
If the following footnote is indented, however, then it'll be included, regardless of how many
blank lines separate it from the footnote definition. See
<https://gist.github.com/notriddle/39ffd52799604bc2cf923fe21a1ea0a9>.
```````````````````````````````` example
Footnotes [^one] [^many].
[^one]:
first paragraph inside footnote
[^many]: first paragraph inside footnote
second paragraph still inside footnote
.
<p>Footnotes <sup><a href="#user-content-fn-one" id="user-content-fnref-one" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-many" id="user-content-fnref-many" data-footnote-ref aria-describedby="footnote-label">2</a></sup>.</p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-one">
<p>first paragraph inside footnote <a href="#user-content-fnref-one" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-many">
<p>first paragraph inside footnote</p>
<p>second paragraph still inside footnote <a href="#user-content-fnref-many" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
A footnote will also break if it's inside another container.
```````````````````````````````` example
> He's also really stupid. [^why]
>
> [^why]: Because your mamma!
As such, we can guarantee that the non-childish forms of entertainment are probably more entertaining to adults, since, having had a whole childhood doing the childish ones, the non-childish ones are merely the ones that haven't gotten boring yet.
.
<blockquote>
<p>He's also really stupid. <sup><a href="#user-content-fn-why" id="user-content-fnref-why" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
</blockquote>
<p>As such, we can guarantee that the non-childish forms of entertainment are probably more entertaining to adults, since, having had a whole childhood doing the childish ones, the non-childish ones are merely the ones that haven't gotten boring yet.</p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-why">
<p>Because your mamma! <a href="#user-content-fnref-why" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
As a special exception, footnotes cannot be nested directly inside each other.
If they are, they act like they're declared beside each other.
```````````````````````````````` example
Nested footnotes are considered poor style. [^a] [^xkcd] [^indent1] [^indent2]
[^a]: This does not mean that footnotes cannot reference each other. [^b]
[^b]: This means that a footnote definition cannot be directly inside another footnote definition.
> This means that a footnote cannot be directly inside another footnote's body. [^e]
>
> [^e]: They can, however, be inside anything else.
[^xkcd]: [The other kind of nested footnote is, however, considered poor style.](https://xkcd.com/1208/)
[^indent1]: indent1
[^indent2]: indent2
.
<p>Nested footnotes are considered poor style. <sup><a href="#user-content-fn-a" id="user-content-fnref-a" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-xkcd" id="user-content-fnref-xkcd" data-footnote-ref aria-describedby="footnote-label">2</a></sup> <sup><a href="#user-content-fn-indent1" id="user-content-fnref-indent1" data-footnote-ref aria-describedby="footnote-label">3</a></sup> <sup><a href="#user-content-fn-indent2" id="user-content-fnref-indent2" data-footnote-ref aria-describedby="footnote-label">4</a></sup></p>
<blockquote>
<p>This means that a footnote cannot be directly inside another footnote's body. <sup><a href="#user-content-fn-e" id="user-content-fnref-e" data-footnote-ref aria-describedby="footnote-label">5</a></sup></p>
</blockquote>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-a">
<p>This does not mean that footnotes cannot reference each other. <sup><a href="#user-content-fn-b" id="user-content-fnref-b" data-footnote-ref aria-describedby="footnote-label">6</a></sup> <a href="#user-content-fnref-a" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-xkcd">
<p><a href="https://xkcd.com/1208/">The other kind of nested footnote is, however, considered poor style.</a> <a href="#user-content-fnref-xkcd" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-indent1">
<p>indent1 <a href="#user-content-fnref-indent1" data-footnote-backref="" aria-label="Back to reference 3" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-indent2">
<p>indent2 <a href="#user-content-fnref-indent2" data-footnote-backref="" aria-label="Back to reference 4" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-e">
<p>They can, however, be inside anything else. <a href="#user-content-fnref-e" data-footnote-backref="" aria-label="Back to reference 5" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-b">
<p>This means that a footnote definition cannot be directly inside another footnote definition. <a href="#user-content-fnref-b" data-footnote-backref="" aria-label="Back to reference 6" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
```````````````````````````````` example
[^foo] [^bar]
[^foo]: [^bar]: 1
.
<p><sup><a href="#user-content-fn-foo" id="user-content-fnref-foo" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-bar" id="user-content-fnref-bar" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-foo">
<a href="#user-content-fnref-foo" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-bar">
<p>1 <a href="#user-content-fnref-bar" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
They do **not** need one line between each other.
```````````````````````````````` example
[^Doh] Ray Me Fa So La Te Do! [^1]
[^Doh]: I know. Wrong Doe. And it won't render right.
[^1]: Common for people practicing music.
.
<p><sup><a href="#user-content-fn-doh" id="user-content-fnref-doh" data-footnote-ref aria-describedby="footnote-label">1</a></sup> Ray Me Fa So La Te Do! <sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-doh">
<p>I know. Wrong Doe. And it won't render right. <a href="#user-content-fnref-doh" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-1">
<p>Common for people practicing music. <a href="#user-content-fnref-1" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
ISSUE 413
```````````````````````````````` example
Lorem ipsum.[^a]
An unordered list before the footnotes:
* Ipsum
* Lorem
[^a]: Cool.
.
<p>Lorem ipsum.<sup><a href="#user-content-fn-a" id="user-content-fnref-a" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
<p>An unordered list before the footnotes:</p>
<ul>
<li>Ipsum</li>
<li>Lorem</li>
</ul>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-a">
<p>Cool. <a href="#user-content-fnref-a" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Test case for more footnotes with list. Note that, while the DOM produced here is similar to
GitHub's DOM (except GitHub reorders all footnotes to the end), they have a weird flexbox setup
that causes lists nested inside footnotes to look really weird.
<https://gist.github.com/notriddle/07360ab169c650b72ab8921089b12456>
```````````````````````````````` example
Songs that simply loop are a popular way to annoy people. [^examples]
[^examples]: * [The song that never ends](https://www.youtube.com/watch?v=0U2zJOryHKQ)
* [I know a song that gets on everybody's nerves](https://www.youtube.com/watch?v=TehWI09qxls)
* [Ninety-nine bottles of beer on the wall](https://www.youtube.com/watch?v=qVjCag8XoHQ)
Songs that simply loop are a popular way to annoy people. [^examples2]
[^examples2]: * [The song that never ends](https://www.youtube.com/watch?v=0U2zJOryHKQ) 2
* [I know a song that gets on everybody's nerves](https://www.youtube.com/watch?v=TehWI09qxls) 2
- [Ninety-nine bottles of beer on the wall](https://www.youtube.com/watch?v=qVjCag8XoHQ) 2
Songs that simply loop are a popular way to annoy people. [^examples3]
[^examples3]: * [The song that never ends](https://www.youtube.com/watch?v=0U2zJOryHKQ) 3
* [I know a song that gets on everybody's nerves](https://www.youtube.com/watch?v=TehWI09qxls) 3
* [Ninety-nine bottles of beer on the wall](https://www.youtube.com/watch?v=qVjCag8XoHQ) 3
.
<p>Songs that simply loop are a popular way to annoy people. <sup><a href="#user-content-fn-examples" id="user-content-fnref-examples" data-footnote-ref aria-describedby="footnote-label">1</a></sup></p>
<ul>
<li><a href="https://www.youtube.com/watch?v=TehWI09qxls">I know a song that gets on everybody's nerves</a></li>
<li><a href="https://www.youtube.com/watch?v=qVjCag8XoHQ">Ninety-nine bottles of beer on the wall</a></li>
</ul>
<p>Songs that simply loop are a popular way to annoy people. <sup><a href="#user-content-fn-examples2" id="user-content-fnref-examples2" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<p>Songs that simply loop are a popular way to annoy people. <sup><a href="#user-content-fn-examples3" id="user-content-fnref-examples3" data-footnote-ref aria-describedby="footnote-label">3</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-examples">
<ul>
<li><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">The song that never ends</a></li>
</ul>
<a href="#user-content-fnref-examples" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-examples2">
<ul>
<li><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">The song that never ends</a> 2</li>
<li><a href="https://www.youtube.com/watch?v=TehWI09qxls">I know a song that gets on everybody's nerves</a> 2</li>
</ul>
<ul>
<li><a href="https://www.youtube.com/watch?v=qVjCag8XoHQ">Ninety-nine bottles of beer on the wall</a> 2</li>
</ul>
<a href="#user-content-fnref-examples2" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a>
</li>
<li id="user-content-fn-examples3">
<ul>
<li>
<p><a href="https://www.youtube.com/watch?v=0U2zJOryHKQ">The song that never ends</a> 3</p>
</li>
<li>
<p><a href="https://www.youtube.com/watch?v=TehWI09qxls">I know a song that gets on everybody's nerves</a> 3</p>
</li>
<li>
<p><a href="https://www.youtube.com/watch?v=qVjCag8XoHQ">Ninety-nine bottles of beer on the wall</a> 3</p>
</li>
</ul>
<a href="#user-content-fnref-examples3" data-footnote-backref="" aria-label="Back to reference 3" class="data-footnote-backref">↩</a>
</li>
</ol>
</section>
````````````````````````````````
Test case for the relationship between link references and footnotes.
<https://gist.github.com/notriddle/5625a3c1cb70b3067a01d7465f9d10f1>
GitHub writes
`My [cmark-gfm]<sup class="footnote-reference"><a href="#examples">1</a></sup>.`
in the first paragraph. This seems like a bug, and it's easier to fix it than
to remain compatible with it <https://github.com/pulldown-cmark/pulldown-cmark/pull/929>.
```````````````````````````````` example
My [cmark-gfm][^c].
My [cmark-gfm][cmark-gfm][^c].
My [cmark-gfm][][^c].
My [cmark-gfm] [^c].
My [cmark-gfm[^c]].
[cmark-gfm]: https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702
[^c]: cmark-gfm is under the MIT license, so incorporating parts of its
test suite into pulldown-cmark should be fine.
My [otherlink[^c]].
[otherlink[^c]]: https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702
.
<p>My [cmark-gfm]<sup><a href="#user-content-fn-c" id="user-content-fnref-c" data-footnote-ref aria-describedby="footnote-label">1</a></sup>.</p>
<p>My <a href="https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702">cmark-gfm</a><sup><a href="#user-content-fn-c" id="user-content-fnref-c-2" data-footnote-ref aria-describedby="footnote-label">1</a></sup>.</p>
<p>My <a href="https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702">cmark-gfm</a><sup><a href="#user-content-fn-c" id="user-content-fnref-c-3" data-footnote-ref aria-describedby="footnote-label">1</a></sup>.</p>
<p>My <a href="https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702">cmark-gfm</a> <sup><a href="#user-content-fn-c" id="user-content-fnref-c-4" data-footnote-ref aria-describedby="footnote-label">1</a></sup>.</p>
<p>My [cmark-gfm<sup><a href="#user-content-fn-c" id="user-content-fnref-c-5" data-footnote-ref aria-describedby="footnote-label">1</a></sup>].</p>
<p>My [otherlink<sup><a href="#user-content-fn-c" id="user-content-fnref-c-6" data-footnote-ref aria-describedby="footnote-label">1</a></sup>].</p>
<p>[otherlink<sup><a href="#user-content-fn-c" id="user-content-fnref-c-7" data-footnote-ref aria-describedby="footnote-label">1</a></sup>]: <a href="https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702">https://github.com/github/cmark-gfm/blob/1e230827a584ebc9938c3eadc5059c55ef3c9abf/test/extensions.txt#L702</a></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-c">
<p>cmark-gfm is under the MIT license, so incorporating parts of its
test suite into pulldown-cmark should be fine. <a href="#user-content-fnref-c" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a> <a href="#user-content-fnref-c-2" data-footnote-backref="" aria-label="Back to reference 1-2" class="data-footnote-backref">↩<sup>2</sup></a> <a href="#user-content-fnref-c-3" data-footnote-backref="" aria-label="Back to reference 1-3" class="data-footnote-backref">↩<sup>3</sup></a> <a href="#user-content-fnref-c-4" data-footnote-backref="" aria-label="Back to reference 1-4" class="data-footnote-backref">↩<sup>4</sup></a> <a href="#user-content-fnref-c-5" data-footnote-backref="" aria-label="Back to reference 1-5" class="data-footnote-backref">↩<sup>5</sup></a> <a href="#user-content-fnref-c-6" data-footnote-backref="" aria-label="Back to reference 1-6" class="data-footnote-backref">↩<sup>6</sup></a> <a href="#user-content-fnref-c-7" data-footnote-backref="" aria-label="Back to reference 1-7" class="data-footnote-backref">↩<sup>7</sup></a></p>
</li>
</ol>
</section>
````````````````````````````````
If a footnote definition is followed by text indented four spaces or one tab, that text will be treated as part of the footnote instead of being an indented code block. To preserve the current behavior, writing code that will be interpreted the same way under both editions, separate the code block from the footnote using an un-indented HTML comment:
```````````````````````````````` example
[^1]: footnote definition text
<!-- -->
// indented code block
fn main() {
println!("hello world!");
}
.
<!-- -->
<pre><code>// indented code block
fn main() {
println!("hello world!");
}
</code></pre>
````````````````````````````````
Footnote definitions no longer need to be separated by blank lines. To preserve the current behavior, if you intentionally want to write a footnote reference followed by a colon at the start of a line, use a backslash escape:
```````````````````````````````` example
[^1]: footnote definition text
[^1]\: this is a reference, rather than a definition
.
````````````````````````````````
If a footnote definition is immediately followed by a list, block quote, or table, it needs to be indented by four spaces to be considered part of the footnote. To preserve the current behavior, writing code that will be interpreted the same way in either edition, you'll need to fall back to HTML syntax, since there's no easy way to write code that the *new* syntax will accept as part of the footnote without the *old* syntax considering it a code block.
When migrating to the new Edition, a table within a footnote can be written like this (under the old Edition, the table is treated as source code):
```````````````````````````````` example
[^1]:
| column1 | column2 |
|---------|---------|
| row1a | row1b |
| row2a | row2b |
.
````````````````````````````````
While [Markdown Guide] claims that you can't put footnote definitions inside lists, block quotes,
or tables. When [I try it][nesttest] in GitHub, footnote definitions are parsed when nested within
lists and blockquotes, but not tables. A footnote definition will interrupt a table if it's at the
start of a line, or just not be parsed if the table has a pipe at the start of the line.
[Markdown Guide]: https://www.markdownguide.org/extended-syntax/#footnotes
[nesttest]: https://gist.github.com/notriddle/169e8735d79639cdf6b5c4b5ba643861
```````````````````````````````` example
* First
[^1]: test
* Second [^1] test
> first
> [^2]: test
> Second [^2] test
First | Second
-----------|----------
first | second
[^3]: test | test [^3]
| First | Second |
|------------|-----------|
| first | second |
| [^4]: test | test [^4] |
> [^5]: * test [^5]
.
<ul>
<li>First</li>
<li>Second <sup><a href="#user-content-fn-1" id="user-content-fnref-1" data-footnote-ref aria-describedby="footnote-label">1</a></sup> test</li>
</ul>
<blockquote>
<p>first</p>
</blockquote>
<table>
<thead>
<tr>
<th>First</th>
<th>Second</th>
</tr>
</thead>
<tbody>
<tr>
<td>first</td>
<td>second</td>
</tr>
</tbody>
</table>
<table>
<thead>
<tr>
<th>First</th>
<th>Second</th>
</tr>
</thead>
<tbody>
<tr>
<td>first</td>
<td>second</td>
</tr>
<tr>
<td>[^4]: test</td>
<td>test [^4]</td>
</tr>
</tbody>
</table>
<blockquote>
</blockquote>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-1">
<p>test <a href="#user-content-fnref-1" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Footnote labels cannot be empty.
```````````````````````````````` example
Test [^] link
[^]: https://rust-lang.org
.
<p>Test <a href="https://rust-lang.org">^</a> link</p>
````````````````````````````````
Footnote labels cannot contain line breaks, even where link labels can.
```````````````````````````````` example
[^foo\
bar]: not a footnote definition
[baz\
quux]: https://rust-lang.org
[first
second]: https://rust-lang.org
[^third
fourth]: not a footnote definition
[baz\
quux]
[^foo\
bar]
[first
second]
[^third
fourth]
.
<p>[^foo<br>
bar]: not a footnote definition</p>
<p>[^third
fourth]: not a footnote definition</p>
<p><a href="https://rust-lang.org">baz<br>
quux</a>
[^foo<br>
bar]
<a href="https://rust-lang.org">first
second</a>
[^third
fourth]</p>
````````````````````````````````
The above rules imply a few cases where something starts with `^`, but actually
parses as a link definition.
```````````````````````````````` example
[^foo
]: https://rust-lang.org
[^foo
]
.
<p><a href="https://rust-lang.org">^foo
</a></p>
````````````````````````````````
Footnote definitions can be indented up to three spaces.
At four spaces, it becomes a code block.
```````````````````````````````` example
footnote [^baz]
footnote [^quux]
[^quux]: x
[^baz]: x
.
<p>footnote <sup><a href="#user-content-fn-baz" id="user-content-fnref-baz" data-footnote-ref aria-describedby="footnote-label">1</a></sup>
footnote [^quux]</p>
<pre><code>[^quux]: x
</code></pre>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-baz">
<p>x <a href="#user-content-fnref-baz" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
Multiple footnotes should be able without needing whitespace in between.
```````````````````````````````` example
Lorem ipsum.[^a][^b]
[^a]: Foo
[^b]: Bar
.
<p>Lorem ipsum.<sup><a href="#user-content-fn-a" id="user-content-fnref-a" data-footnote-ref aria-describedby="footnote-label">1</a></sup><sup><a href="#user-content-fn-b" id="user-content-fnref-b" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-a">
<p>Foo <a href="#user-content-fnref-a" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-b">
<p>Bar <a href="#user-content-fnref-b" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````
This does work already:
```````````````````````````````` example
Lorem ipsum.[^a] [^b]
[^a]: Foo
[^b]: Bar
.
<p>Lorem ipsum.<sup><a href="#user-content-fn-a" id="user-content-fnref-a" data-footnote-ref aria-describedby="footnote-label">1</a></sup> <sup><a href="#user-content-fn-b" id="user-content-fnref-b" data-footnote-ref aria-describedby="footnote-label">2</a></sup></p>
<section data-footnotes class="footnotes"><h2 class="sr-only" id="footnote-label">Footnotes</h2>
<ol>
<li id="user-content-fn-a">
<p>Foo <a href="#user-content-fnref-a" data-footnote-backref="" aria-label="Back to reference 1" class="data-footnote-backref">↩</a></p>
</li>
<li id="user-content-fn-b">
<p>Bar <a href="#user-content-fnref-b" data-footnote-backref="" aria-label="Back to reference 2" class="data-footnote-backref">↩</a></p>
</li>
</ol>
</section>
````````````````````````````````