Document header

#Writing the header

The header is an attribute group with a * in front of it and no body. It is the one construct written with the * sigil.

*(
    title: The 68–95–99.7 rule
    description: However wide the band, the share of a normal distribution inside it depends only on k.
    tags: statistics, probability, normal distribution
    lesson
)

scene{
    …
}

Inside the brackets it is written like any attribute group: one key: value per line, or several on one line separated by semicolons, and the flags bare — lesson, not lesson: true (Bare and negated booleans).

#The header attributes

The header takes five attributes: title, the one it requires; description; tags; and two flags, lesson and template. What each does, its type and its default are in Attributes below.

There is no author: an internote's authors are the accounts that co-own it on Internote, not a header field, and a key outside the five is refused by name.

*(
    title: Free fall
    author: Physics teaching team
)

The compiler also refuses a header with no title — required attribute `title` is missing — and more than seven different tags — A maximum of 7 tags is allowed.

#Placement

The header is the first node of the file; only comments may come before it. Below it the document holds two nodes — scene, in reading order, and cite, which declares a source and renders nothing where it is written — with directives such as @data and @let free to stand between them:

// A stone dropped from rest.
*(
    title: Free fall
    tags: physics, mechanics
)

@let(g: 9.81)

scene{
    After one second the stone has fallen {{g / 2}} m.
}

cite#galileo1638(
    authors: Galilei, G.
    year: 1638
    title: Two new sciences
)

The compiler refuses:

• a header anywhere but first — after a directive or a scene, a second header, or one inside a file spliced in with @include: the document header must be the first node of the document;
• any other node at the top level, such as a graph outside a scene: node `graph` is not allowed here (allowed: scene, cite).