Expresso.Element.Math (expresso v0.1.0)

An element that shows a formula in MathML

The math entity takes the formula in one of two forms:

The MathML as its first argument, from the <math> tag to the </math> tag. Give the math tag the attribute display="block" for a formula on its own line, which is the usual form on a slide.
The LaTeX in the tex option. typeset/1 makes the MathML with Expresso.Element.Math.Tex, in one run of Node for the deck.

A browser renders MathML Core without a script and without a font file, and each browser of the floor of this project supports it. The text goes into the document as it is, as the text of a text area does. docs/math-parts.md gives the design of the LaTeX.

Summary

Types

t()

The struct of a math element

Functions

check(math)

Check a math element, and write its lines into one formula

get_assigns(math)

Make the assigns of the render function from the struct

parts(mathml)

Give the names of the parts of the MathML of a formula, in the order of the MathML, without a repeat

place(deck)

Replace each move_to of the parts of a deck with a move that the browser measures

render(assigns)

Make the HTML of a math element

typeset(deck, render \\ &Tex.render!/1)

Make the MathML of each math element of a deck with the tex option

Types

t()

@type t() :: %Expresso.Element.Math{
  __spark_metadata__: term(),
  at: term(),
  class: term(),
  easing: term(),
  effect: term(),
  el: term(),
  elements: term(),
  line_names: term(),
  lines: term(),
  morph: term(),
  on: term(),
  reveal: term(),
  rewrite_lines: term(),
  signature: term(),
  speed: term(),
  steps: term(),
  tex: term(),
  text: term(),
  two_step_lines: term()
}

The struct of a math element

Functions

check(math)

@spec check(t()) :: {:ok, t()} | {:error, String.t()}

Check a math element, and write its lines into one formula

A math element has one source: the MathML, the tex option, or line entities. The function writes the lines into the LaTeX of one formula of the environment aligned, a row for each line, with the relation, the term and the reason in three columns. A rewrite entity becomes a line first, with Expresso.Element.Math.Rewrite.expand/1. Each line becomes a part with its name, and with reveal true it shows at its own step. The function then checks the name of each \part{name}{…} and \id{name}{…} of the LaTeX. The entity of the DSL and Expresso.Builder call this function.

get_assigns(math)

@spec get_assigns(t()) :: map()

Make the assigns of the render function from the struct

The key overlay holds the attributes of the overlay contract, from Expresso.Overlay.Render.attributes/1.

parts(mathml)

@spec parts(String.t()) :: [String.t()]

Give the names of the parts of the MathML of a formula, in the order of the MathML, without a repeat

A part has a name in the attribute data-part, from \part{name}{…}, or in the attribute class, from \class{name}{…}. The list also holds the classes that Temml writes, such as tml-display.

iex> Expresso.Element.Math.parts(~s(<math class="tml-display"><mrow data-part="redex"><mi class="bind">f</mi></mrow></math>))
["tml-display", "redex", "bind"]

place(deck)

@spec place(Expresso.Deck.t()) :: Expresso.Deck.t()

Replace each move_to of the parts of a deck with a move that the browser measures

An on entity of a part of a formula can take move_to, the name of a different part of the same formula. The place of a part comes from the fonts of the browser, so the render cannot measure it. This function puts x: "var(--to-x-name)" and y: "var(--to-y-name)" into set, and the presenter script gives the part these two custom properties: the distance from the center of the part to the center of the part name. A browser with no script then shows the part at its place.

Expresso.Renderer calls this function after typeset/1. It raises for a name that the formula does not have, and for a part that moves to itself.

render(assigns)

@spec render(map()) :: Phoenix.HTML.safe()

Make the HTML of a math element

The MathML goes into one block element inside the root tag.

typeset(deck, render \\ &Tex.render!/1)

@spec typeset(Expresso.Deck.t(), ([String.t()] ->
                              [Expresso.Element.Math.Tex.result()])) ::
  Expresso.Deck.t()

Make the MathML of each math element of a deck with the tex option

Expresso.Renderer calls this function before the render. One run of Node makes the MathML of each formula of the deck, and the watch mode keeps the MathML of each source from one render to the next, so a change of one slide runs Node for the formulas that changed. A deck with no LaTeX runs no Node.

render makes the MathML of a list of sources. The default is Expresso.Element.Math.Tex.render!/1, and a test can give a function that needs no Node. The function raises an ArgumentError with the message of Temml for a source that Temml cannot read.