Syntax reference

The slipshow syntax can be described in several parts.

One part is the document itself, disregarding any slipshow-specific data. The syntax is (almost) exactly markdown, but there are a few modifications that are described and justified here.
Since you need to add metadata to describe the flow of your presentation, slipshow includes some special syntax to attach metadata to add to specific parts of your presentation. The “attachment” syntax is very close to what other markdown extension do, but expand and modifies some constructs. This is explained and justified in the next section.
Finally, there is the syntax for the metadata themself. Slipshow include many keyword to allow you to describe the flow of your presentation in a convenient way.

Defining a document

The slipshow syntax is based on CommonMark, whose syntax is well specified. The “60 second to learn Markdown” is a good and quick way to learn the syntax.

Some extensions to CommonMarkd are quite common, and available in the slipshow syntax: - The table extension, as specified here. - The math extension, as specified here. - The strikethrough extension, as specified here.

Warning

Quotes do not have the same syntax as commonmark!

In addition to extensions, there is one modification to the Markdown syntax! The markdown syntax for block quotation is not considered to enclose a quotation. It instead simply groups blocks together, without assigning a default meaning to the group. The meaning can be given using the attribute syntax.

For block quotes, use the html syntax until better support is added! (Slipshow is still in beta version.)

Attaching metadata

Metadatas are the backbone of your slipshow presentation! The tricky part is that we don’t want it to cripple the readability of the source. Still, it is in my opinion and experience much better to have it mixed inside the document. It makes it much easier to reason locally on what the presentation will look like.

Attaching metadata is done very similarly to both pandoc’s markdown and djot.

Metadatas (also called attributes) are enclosed in curly braces: {}. We can attach metadata to two kind of document parts: blocks (such as paragraphs, code blocks, title, definitions, …) and inlines (such as words or group of words, code spans, links, images, …).

Block metadata

To add attributes to a block, put the curly braces on an (otherwise empty) line just above. That is, for a heading:

{the attributes}
# The title

See the next section for the content on the attributes. If you want to add an attribute to a group of several blocks, indent all of them using >. For instance

{the attributes}
> Some text
>
> ```
> A code block
> ```

An attribute cannot have line breaks. However, if two lines of attributes are in a row, they are merged.

An attribute that is followed by an empty line is a _standalone attribute_. They are useful in the context of slipshow, to give an instruction (such as a pause) in the flow of the presentation, without being tied to a specific element!

Some text

{a standalone attribute}

Some other text

Inline metadata

If you want to give attributes to inline elements, the syntax is quite similar: attributes are enclosed in curly braces. What changes is how they are attached to a specific element.

Attributes are attached to the inline element they touch. For instance:

Some text and{A} some {B}other text and {C} finally an end.

Works with **bold**{D} and other `inline elements`{E}

In this example, A is attached to and, B to other, C is a standalone attribute, D is attached to **bold** and E to `inline elements`.

If you want to attach an attribute to a group of inlines, you can use the [...]{attributes} syntax. For instance:

Works with [groups of **bold** and other `inline elements`]{F}

However, sometimes putting long attributes in the middle of the text can hurt readability. Often, the attributes are the same and are repeated, which makes it even worse. Slipshow eases this by using referenced attributes. Similarly to footnotes and referenced links, they text only contains a reference, and the attribute itself is defined elsewhere:

Some [text][A] [with][A] [many][A] [attributed][A] [words][A].

[A]: {many long attributes}

Not perfect, but much better than the version where all words are given the attributes separately.

Describing your presentation flow

Now that we know how to assign attributes to a part of the document, we can continue with the “true” slipshow syntax: the metadata itself.

This metadata is used to tell slipshow how the presentation should go. When to pause, when to move the window, down or up.

Let’s start first with the “general” syntax for the content inside the curly braces.

{#fermat .theorem pause up-at-unpause=title1 exec-at-unpause="script1 script2"}
Some content

Attributes are separated by space.

A word starting with # gives an id to the associated elements. For instance, above, the fermat id is given to the content. Ids are used to refer to other elements, for instance title1, script1 and script2 are likely to be reference to other ids in the example above.

A word starting with . is a class. Classes are used both controlling the layout, especially with themes. For instance, the content above is assigned the theorem class, which will make it render as a theorem. A complete list of class supported by slipshow is available later in this section, but custom themes might add some more.

A single word is a “flag attribute”. In the example above, pause is a flag attribute. The meaning of all slipshow attributes is given later in this section!

Key-value attributes are defined using an equal sign (=). They need a key, and a value. If the value contains spaces or other dubious characters, they should be enclosed in quotes. The quotes are not part of the value of they key attributes! In the example above, the key up-at-unpause is given value title1, while the key exec-at-unpause is given the value script1 script2.

Some attribute can be used both as a flag attribute and as a key-value attribute.

List of classes

The following classes are meant to be added to a block element, and will display the element as a presentation block. They all accept a title=... attributes.

block to display a regular presentation block,
theorem to display a theorem,
definition to display a definition,
example to display an example,
lemma to display a lemma,
corollary to display a corollary,
remark to display a remark.

List of attributes

Pause attributes

pause

The pause attribute tells the slipshow engine that there is going to be a pause at this element. This element and every element after that in the document will be hidden.

Each time the user advances in the presentation (e.g by pressing the Down key), the first pause or step is consumed, possibly triggering some effects.

step

Same as pause, but no elements is hidden. Only used to activate effects when consumed.

Action attributes

These attributes are actions that will be executed when a pause or step attribute attached to the same element is consumed. All of them accepts a value, consisting of the id of an element to apply the action to.

down or down-at-unpause: Moves the screen untils the element is at the bottom of the screen.
up or up-at-unpause: Moves the screen untils the element is at the top of the screen.
center or center-at-unpause: Moves the screen untils the element is centered.
focus or focus-at-unpause: Focus on the element by zooming on it. Possible to specify multiple ids.
unfocus or unfocus-at-unpause: Unfocus by going back to the last position before a focus.
static-at-unpause: Make the element static. By “static” we mean the css styling position:static; visibility:visible will be applied. Possible to specify multiple ids.
unstatic-at-unpause: Make the element unstatic. By “unstatic” we mean the css styling position:absolute; visibility:hidden will be applied. Possible to specify multiple ids.
reveal-at-unpause: Reveal the element. By “revealing” we mean the css styling opacity:1 will be applied. Possible to specify multiple ids.
unreveal-at-unpause: Hide the element. By “unrevealing” we mean the css styling opacity:0 will be applied. Possible to specify multiple ids.
exec-at-unpause: Execute the slipscript. Possible to specify multiple ids.

Custom scripts

Use a slipscript code block to add a script, and exec-at-unpause to execute it.

{pause exec-at-unpause}
```slip-script
alert("Alerts are very annoying !")
```

If a script has a “permanent” side-effect, it has to provide a way for slipshow to revert it. There are currently two experimental ways to do that. The first one (but not the preferred one) is return an undo function:

{pause exec-at-unpause}
```slip-script
let elem = document.querySelector("#id")
let old_value = elem.style.opacity;
elem.style.opacity = "1";
return {undo : () => { elem.style.opacity = old_value }}
```

However this is not always easy to compose. The other option is to use the slip.onUndo function to register callbacks to be run on undo.

{pause exec-at-unpause} ```slip-script let i = 0 let incr = () => {

slip.onUndo(() => { console.log(–i)}) console.log(i++);

} incr(); incr(); incr(); ```

Using slip.onUndo inside an undo callback should not be a problem. (Actually, it might be recommended.)

Slipshow provides a few utils function, using the callback mechanism just desribed.

You can use slip.setStyle(elem, style, value) where elem is an element, and style and value a string to set a style and register an undo callback.

You can also use slip.setClass(elem, className, bool) where elem is an element, style is a string and bool a boolean to add or remove a class and register an undo callback.

You can also use slip.setProp(object, propName, value) where object is an element, propName is a string and value a value to set a property and register an undo callback.

Through the slip object, slip-scripts also have access to the actions defined above. Again, they work using the onUndo callbacks. They can be used to programmatically call the actions defined above.

{pause exec-at-unpause}
```slip-script
let elem = document.querySelector("#id")
slip.up(elem);
```

Note that if an API above accepts multiple IDs (as unstatic-at-unpause for instance), then the function expects a list of elements:

{pause exec-at-unpause}
```slip-script
let elems = document.querySelectorAll(".class")
slip.unstatic(elems);
```

Finally, the slip.state object is persisted between scripts. (Other functions are specific to a script. This might change in the future, but slip.state is safe to use).

Use it with slip.setProp to not forget undoing the changes!