# Extensions

## Footnotes

This is a footnote in history[1] with mutiple references[1] and even text references

This is no longer the footnote.

Can we make footnotes in footnotes[2] ?

Not the footnote

Not the footnote but a reference to an empty footnote[3]

Not a footnote [^]

[^]: not a footnote.

## Strikethrough

The stroken emph.

Nesting the nest emph stroke emph emph strikeagain

There must be no blanks after the opener and before the closer. This is ~~ not an opener and ~~this won't open that does.

- Here we have stroken `code`.
- Here we have nested stroken ok

## Math

The inline \(\sqrt{x^2-1}\) equation.

There must be no blanks after the opener and before the closer. This makes so you can donate $5 or $10 dollars here and there without problem.

There is no such think as nesting \(\sqrt{x^2-1}\)+3\(+3\). As usual delimiters can be $escaped$ \(\sqrt{16\$}\)

Amazing, this is hyperlinked math \(3x^2\)

The HTML renderer should be careful with \(a < b\) escapes.

Display math can be in `math` code blocks.

\[ \left( \sum_{k=1}^n a_k b_k \right)^2 < \Phi \]

But it can also be in \[ \left( \sum_{k=1}^n a_k b_k \right)^2 < \Phi \]

## List task items

- Task open

- Task done

- Task done

- Task done (U+2713, CHECK MARK)

- Task done (U+2714, HEAVY CHECK MARK) Indent

- Of course this can all be nested

  - Task done (U+10102, AEGEAN CHECK MARK) It will be done for sure.

        code block

    Not a code block

  - Task done

  - Task cancelled Paragraphy

  - Task canceled

        we have a code block here too.

  - [x]Not a task

  - [x] Not a task

- a

      Code

  Not code

-     Code

  Not code

## Tables

A sample table:

Id | Name | Description | Link
--- | --- | --- | ---
1 | OCaml | The OCaml website | https://ocaml.org
2 | Haskell | The Haskell website | https://haskell.org
3 | MDN Web docs | Web dev docs | https://developer.mozilla.org/
4 | Wikipedia | The Free Encyclopedia | https://wikipedia.org

Testing these non separator pipes.

Fancy | maybe | hu|glu
--- | --- | ---
a | b | `code |` | bl|a
not | two cols | \(\sqrt(x^2 - 1)\) |

A table with changing labels and alignement:

h1 | h2
--- | ---
1 | 2
h3 | h4
3 | 4

A simple header less table with left and right aligned columns

1 | 2

The simplest table:

1 | 2

A header only table:

h1 | h2
--- | ---

Maximal number of columns all rows defines number of colums:

h1 | h2 | h3 |
--- | --- | --- | ---
left | center | right |
ha! | four | columns | in fact
|  |  | a

Header less table:

header | less
this | is

Another quoted header less table with aligement

> header | less
> again | aligned

This is an empty table with three columns:

## Attributes

### Block attributes

This is a paragraph with the `my-id` is.

I have `your-id`, not mine

I have `his-id`, not mine, not yours

#### This is a title with the `.blue` class

- This is an item where `key` has value `value`.
- It is not possible to attach attributes to list items... yet

I'm a paragraph with many attributes

I have much more attribute than the previous one, since they stack

I have your id

I have a lot of class: `class1`, `class2`, `class3` and `class4`

Me too!

But spaceships matter.

Some word

### Inline attributes

not a block attribute, but a standalone inline attribute, as I have content in the line.

In the middle of paragraphs, work.

Similarly, at the end, they work

Without specified delimitations, inline attributes are either or attached to the left-closest.

Inline attributes can refer to many including with inline.

Attributes can be nested: link with, attrs with link, attrs within.

Attributes can be attached without squares, for instance this has an id. This `codeblock`! This . Links. Emphasis and italic1 italic2!

Testing strikethrough.

## Title with an id

### Attributes definition

We can provide attributes definition to avoid cluttering a line with attributes.

Attributes attached to attribute definition do nothing:

A b c

However, for link definition, they are present:

A b c

1. And it can have lazy continuation lines and multiple paragraphs

   If you indent one column after the footnote label start.

       cb

   - list item ablc
   - another item
   ↩︎︎1 ↩︎︎2 ↩︎︎3

2. This gets tricky but I guess we could have a footnote[4] in a footnote. Also footnote[1] in footnotes[2] is[3] tricky for getting all back references rendered correctly.

   Second footnote

   ↩︎︎1 ↩︎︎2
3. ↩︎︎1 ↩︎︎2