md4c/test/spec-insert.txt

# Insert

With the flag `MD_FLAG_INSERT`, MD4C enables recognition of insert spans
using the `++text++` syntax. A pair of plus signs on each side wraps
the content, which the HTML renderer outputs as `<ins>`.


## Basic recognition

```````````````````````````````` example
++Hello, world!++
.
<p><ins>Hello, world!</ins></p>
.
--finsert
````````````````````````````````

Multiple independent insert spans may appear in the same paragraph:

```````````````````````````````` example
++first++ and ++second++
.
<p><ins>first</ins> and <ins>second</ins></p>
.
--finsert
````````````````````````````````

Insert may open after regular text characters:

```````````````````````````````` example
colo++u++r
.
<p>colo<ins>u</ins>r</p>
.
--finsert
````````````````````````````````


## Opt-in behavior / Flag required

Without `MD_FLAG_INSERT` the `++` sequence is treated as literal text:

```````````````````````````````` example
++insert++
.
<p>++insert++</p>
.
````````````````````````````````


## Nested inline spans

Emphasis inside an insert span:

```````````````````````````````` example
++very *important* text++
.
<p><ins>very <em>important</em> text</ins></p>
.
--finsert
````````````````````````````````

Strong emphasis inside an insert span:

```````````````````````````````` example
++**bold** and _italic_++
.
<p><ins><strong>bold</strong> and <em>italic</em></ins></p>
.
--finsert
````````````````````````````````

Inline code inside an insert span:

```````````````````````````````` example
++inserted `code`++
.
<p><ins>inserted <code>code</code></ins></p>
.
--finsert
````````````````````````````````

A link inside an insert span:

```````````````````````````````` example
++inserted [link](http://example.com)++
.
<p><ins>inserted <a href="http://example.com">link</a></ins></p>
.
--finsert
````````````````````````````````

Insert may appear inside link text:

```````````````````````````````` example
[inserted ++text++](http://example.com)
.
<p><a href="http://example.com">inserted <ins>text</ins></a></p>
.
--finsert
````````````````````````````````


## Whitespace rules

An insert delimiter cannot open an insert span when immediately followed
by whitespace:

```````````````````````````````` example
++ insert++
.
<p>++ insert++</p>
.
--finsert
````````````````````````````````

An insert delimiter cannot close an insert span when immediately preceded
by whitespace:

```````````````````````````````` example
++insert ++
.
<p>++insert ++</p>
.
--finsert
````````````````````````````````


## Delimiter length

A single plus sign is not insert delimiters:

```````````````````````````````` example
+insert+
.
<p>+insert+</p>
.
--finsert
````````````````````````````````

Longer plus sign runs are not split into insert delimiters:

```````````````````````````````` example
+++insert+++
.
<p>+++insert+++</p>
.
--finsert
````````````````````````````````


## Unmatched delimiters

An opening delimiter with no matching closer is literal:

```````````````````````````````` example
++insert
.
<p>++insert</p>
.
--finsert
````````````````````````````````

A closing delimiter with no matching opener is literal:

```````````````````````````````` example
insert++
.
<p>insert++</p>
.
--finsert
````````````````````````````````

If the length of the opener and closer doesn't match, the insert is
not recognized.

```````````````````````````````` example
This ++text+++ is curious.
.
<p>This ++text+++ is curious.</p>
.
--finsert
````````````````````````````````


## Paragraph boundary stops resolution

An insert span cannot cross a paragraph boundary:

```````````````````````````````` example
This ++has a

new paragraph++.
.
<p>This ++has a</p>
<p>new paragraph++.</p>
.
--finsert
````````````````````````````````


## Suppression inside code

Plus signs inside code spans are treated as literal text:

```````````````````````````````` example
`++code++`
.
<p><code>++code++</code></p>
.
--finsert
````````````````````````````````

Plus signs inside fenced code blocks are treated as literal text:

```````````````````````````````` example
```
++code++
```
.
<pre><code>++code++
</code></pre>
.
--finsert
````````````````````````````````


## Interaction with other extensions

Insert may appear inside table cells:

```````````````````````````````` example
| Feature | Status |
| --- | --- |
| Insert | ++done++ |
.
<table>
<thead>
<tr><th>Feature</th><th>Status</th></tr>
</thead>
<tbody>
<tr><td>Insert</td><td><ins>done</ins></td></tr>
</tbody>
</table>
.
--finsert --ftables
````````````````````````````````

### Spoilers (requires `MD_FLAG_SPOILERS`)

Insert may appear inside a spoiler span:

```````````````````````````````` example
||++inserted spoiler++||
.
<p><x-spoiler><ins>inserted spoiler</ins></x-spoiler></p>
.
--finsert --fspoilers
````````````````````````````````

A spoiler span may appear inside an insert:

```````````````````````````````` example
++||inserted spoiler||++
.
<p><ins><x-spoiler>inserted spoiler</x-spoiler></ins></p>
.
--finsert --fspoilers
````````````````````````````````