# Markdown syntax

Mathigon’s courses are written in a custom flavour of Markdown. Most standard syntax (titles, bold, italic, links, etc.) is supported, but we have added many new elements, and updated the behaviour of some existing ones.

Here is the basic outline of a chapter:

# Chapter Title

> color: #f42621
> description: Here is a custom course description
> id: step-1
> section: section-id

## First section

Here is a paragraph

---
> id: step-2
> goals: my-goal

Here is another paragraph


Notice that every chapter is split into multiple short steps, divided by the --- lines. Every section contains some metadata at the beginning, in lines starting with a >. The metadata is parsed as YAML. (Note that the > usually indicates block quotes in standard Markdown syntax.)

The # H1 heading is the title of the entire course. Every step that starts with an # H2 heading creates a new chapter/section, and you can use the > section: metadata to (optionally) specify a custom ID for this chapter. This ID will appear in the URL, for example /course/<course-id>/<section-id>.

Every step should have a unique id. You can also specify an optional title, as well as goals, which is a space-separated list of events that need to be triggered before the next step is revealed.

## Equations and code blocks

Content between backticks is parsed as AsciiMath and converted to MathML. If you want to parse it as code or LaTeX instead, you can specify the language at the beginning:

The probability of rolling a 6 is (1+x)/3.
Here is some Python code: {py} x = 0
Here is some LaTeX code: {latex} \frac{1}{2}


There are a few minor differences compared to the standard AsciiMath syntax. Most importantly, it is possible to have arbitrary multi-letter variables, e.g. ab would become <mi>ab</mi> not <mi>a</mi><mi>b</mi>. To create multiple chained single-letter variables, simply add a space in between, e.g. a b.

Note: there are special functions for adding inline elements inside equations.

## Blanks and input fields

You can create blanks for students to fill in using double square brackets. These can contain either be a single number (for input field) or multiple words separated by | (for multiple choice popups).

Input fields except the solution both as digits, or as a typed number string. For multiple choice questions, the first choice is always the correct one (but the answers are shuffled when displayed to students).

There are numbers like [[10]] or [[ten]] and [[many|few|no]] choices.


You can provide specific hints for these blanks, or specify ranges of possible answers:

Accept answers between 95 and 105 (inclusive):
[[100 ± 5]]

Show a hint when students make a mistake:
[[100 (Here is a hint.)]]

Show a series of hints if students make repeated mistakes:
[[100 (Here is the first hint. | Here is the second hint.)]]

Show specific hints for common errors:
[[100 (50: Double that number. | 100: Half that number. | Here is a hint.)]]


## Custom classes, attributes and tags

For customisation and styling, it is possible to add ids, classes and attributes to paragraphs or inline elements. Simply start the body of that element with the required CSS selector inside {}:

{.class1.class2(attr="value")} Some _{#id1} text_ and [{.red} link](url).


You can even use this method to change the tag name of an element:

Here is a span element: _{span.red} Text_


## Variable sliders

In order to make the content as dynamic and interactive as possible, you can easily add inline variables that can be manipulated by the student. There is a separate syntax for initialising variables (resulting in interactive sliders) and expressions that depend on these variables. This example would produce a slider for a variable a that is initially 2 and can be changed from -8 to 8 in steps of 2:

The square of ${a}{a|2|-8,8,2} is${a*a}. The square root is ${sqrt(a)}.  You can add external links just like in normal markdown: Here is a [link](https://mathigon.org).  In addition, you can use the bio: or gloss: prefix to add biography or glossary popups. The corresponding IDs must match one of the items in the corresponding YAML files in the shared directory: The force of [gravity](gloss:gravity) was first explained by [Newton](bio:newton).  ## Targets and action buttons You can add action buttons that execute a certain snipped of JavScript code: Let's [increment](action:fn()) the  Other than variable sliders, glossary and biography popups, there are a number of different inline elements. The -> symnol greates a target pointer to specific elements of the page. If users hover over the link, Mathigon will highlight all elements that match the given CSS selector (and, if needed, scroll them into view.) You should try hovering over the [biography button](->#s1.bio).  Note: Replace whitespace in the CSS query selector by _s, so that the string remains a valid “URL”. You can add coloured pills, for example to visualise different variables that correspond to specific elements in a diagram. The supported colours are red, purple, blue, teal, green, lime, yellow and orange: Here is [a red pill](pill:red) and [a yellow pill](pill:yellow).  TODO: target elements… ## Inline elements in equations You can also add any of these elements within AsciiMath equation blocks, using a few different functions: Normal Markdown Inside equations A [[blank \ choice]] x + blank(y, "choice") An input [[10]] x + input(10) + y A [pill](pill:red) x + pill(y,"red") A [{.green} target](target:px) x + pill(y,"green","px") A variable instance${y * 2} x + var("y * 2")

These elements can then be used in arbitrarily nested equations:

blank("a","b")/(input(10) + var("x")) = sqrt(pill(x + y, "blue"))


## Block elements

Rather than using the {...} syntax for adding classes or elements, you can wrap elements in blocks using ::: symbols:

::: .theorem(style="background: red")

Here is some text.

:::


The syntax for specifying tag names, classes, IDs and attributes is the same as in the previous section.

Some components also also allow chaining of multiple blocks:

::: column.grow

This column will grow to fill the available space

::: column(width=300)

This column is 300px wide.

:::


## Reveals

Consecutive steps are automatically hidden and revealed when students complete all the required exercises and goals. However, you can also add content within a step that is dynamically revealed: paragraphs, individual words, or even elements of an SVG diagram.

The syntax is the same as for custom classes and attributes: you just need the .reveal class and a when="" attribute with a space-separated list of all required goals:

Here is a paragraph with a blank: [[10]]

{.reveal(when="blank-0")} Here is another blank: [[20]]

{.reveal(when="blank-1")} Here is another blank: [[30]]


Notice that blanks within a step automatically indexed, staring at 0.

It is also possible to change the animation type, duration and delay of these reveal animations:

{.reveal(when="blank-0" animation="pop" delay=1000 duration=400)} Show me...


## Special characters

You can add any of these emoji using their name:

Hey :smile:


You can create non-breaking whitespace by prefixing it with a \:

The answer is 12\ m. The price us US\$\ 50.


## Custom HTML

Any content indented by four characters is parsed a Pug and converted to HTML:

Here is a paragraph

div
img(src="images/example.jpg")
.caption Here is some custom HTML


Pug content before the start for the first step can be used to define mixins than are accessible in all later Pug blogs.

All relative urls in src and href attributes are parsed relative to the root directory for this chapter.

You can use the .md class to parse Markdown within HTML blocks;

This is _markdown_.

div This is not markdown.
div.md This _is_ markdown.


TODO…

## Audio Narration

Mathigon will automatically generate audio narrations for all text. You can prevent this behaviour using the .no-voice class.

Can you read this _{.no-voice} silent_ text to me.


You can use the voice= attribute to override the custom text-to-speech parser. However, this should only be used rarely – for example, Mathigon can automatically translate equations into spoken text.

Here is an equation: _{span(voice="a squared + b squared")} a^2 + b^2_.