All that can be achieved by this:

\documentclass{book}
\usepackage[stdclass, all]{lix}

\lang      {danish}
\size      {letter}
\cover     {path/to/front.pdf}{path/to/back.pdf}
\margins   {22mm}{20mm}{21mm}{40mm}
\title     {A Cool Title}
\subtitle  {And a Cool Subtitle}
\authors   {Nicklas Vraa}{Another Guy}{And Another}
\date      {01/01/2023}
\isbn      {123456789}
\license   {CC}{nc}{3.0}{My Company}
\edition   {3}{2023}
\watermark {DRAFT}{black!10}

\begin{document}
% ... No need for \maketitle

\h{Introduction}
% ...

    \code{my_snippet}{python}{
    import numpy as np
    % ...
    }{This code does this and that...}

% ...

    \fig{ny_figure}{0.8}{path/to/image.png}{This figures explains how...}

% ...

\end{document}

Imagine the LaTeX code, you would have to write to achieve the same - even when using appropriate packages. The layout of each element should be customized by defining a custom class that builds on top of one of the standard classes. Examples are shown later.

Advantages:

• The source code of a document becomes as easy to read and understand as Markdown and is drastically shorter.
• The style of a document is completely separated from its content, and keeping a consistent style is simpler.
• Configuring your document is simpler, because you don't interface directly with individual packages, which may employ different syntax.
• Creating your own class, which implements a custom look-and-feel, is much easier.

Disadvantages:

• If one wants to change their document into a class that has not been defined using this package, there may be difficulties when compiling. To address this, I've recreated the IEEEtran class, as a reference for how to reimplement an existing look using LiX.
• You do not have the extreme fine-grained control over your custom class, as you would with pure LaTeX.
• The command names are not as descriptive as standard LaTeX. Minimal impact on source-code readability was prioritized.

Insert algorithms into your document. Simply type your algorithm in plain text and mix in math typesetting whenever you require, between $-signs. No need for any escaped \keywords.

...
    \algo{label}{
    % Your algorithm.
    % $some+math$
    }{caption}
...

Algorithms will be subtly highlighted. A label is mandatory, but caption is optional. Indent the block four spaces, as these will be gobbled (removed) in the resulting pdf. This is for better readability in the source file. I recommend indenting all algorithms, tables, figures, etc., to better distinguish them from regular text.

A collection of essential commands and aliases.

• \abstract{summary of findings}
  Alias: \blurb{...} (for books).
• \add{path/to/file.tex/pdf}
  Inserts the tex-code from the given file, exactly like \input{}, but also handles pdf files, which are inserted as pages. If starred, i.e. add*{}, the given pdf will become the background of the current page.
• anchor{position}{...}
  Aligns its content either left, right or center.
• \authors{first}{second}{...}{sixth}
  Handles six entries. Alias: \author{...}.
• \by{name}{email}{path/to/image.png}
  Byline, image is optional.
• \date{01/01/2023}
  The command \today is available.
• \idnum{123456789}
  Could be any alphanumeric.
• \keywords{this, that, ...}
  Alias: \subjects {this, that, ...}.
• \lang{language}{cus-tom, hyphena-tion, rules}
  Localizes text and sets hyphenation rules. Custom list is optional.
• \subtitle{Some Buzzwords}
  Alias: \slogan{...}.
• \title{A Catchy Title}
  Alias: \publication {...}.
• \toc
  Generate table of contents.
• \url{text}{link}
  E.g. {label}{actual url}
• \cols{n}{...}
  Horizontally align content.
  Use \begin{columns}{n} ... \end{columns} if \cols doesn't work. \
• \watermark{Text}{color!opacity}
  Add text-based watermark, e.g. DRAFT, or CONFIDENTIAL with an optionally specified color and opacity, e.g. blue!100. Defaults to gray!50, if not specified.
• \shield{Text}{opacity}
  Overlays every page with an invisible wall of text to prevent easy extraction of text, i.e. copy-pasting. Opacity is optional and between 0 (invisible) and 1 (black). E.g. \shield{COPYRIGHTED, NICE TRY}.
• \np and \bl
  The first is an alias for \newpage and the second forces a blank line.

In-class commands:

• \authorfont{\...}
  Apply styling commands to the author text.
• \use{pkg1, pkg2, ..., pkgN}
  Import packages. Simpler alias of \usepackage.
• \wrap{prepend...}{append...}
  Insert code immediately after \begin{document} and (optionally) immediately before \end{document}.

Insert internal code blocks into your document.

...
    \code{label}{language}{
    % Your code.
    }{caption}
...

Or import external code from a file using the starred version.

\code*{label}{language}{path/to/file}{caption}

Code-blocks will be subtly highlighted according to the given language. A label is mandatory, but caption is optional. For no highlighting, set the language to text. For internal code block, indent the block four spaces, as these will be gobbled (removed) in the resulting pdf. This is for better readability in the source file. I recommend indenting all code-blocks, tables, figures, etc., to better distinguish them from regular text.

Add a cover to your document, as in the front and back of a book.

• \cover{path/to/front.pdf}{path/to/back.pdf}
  The images have to be pdf-files. The starred version will not print the title, author, etc. on top of the cover. This is useful, if the cover already includes these. Should be called before \begin{document}.

In-class commands:

• \addFrontCover
• \addBackCover

Place figures, i.e. images and illustrations in your document.

• \fig{label}{scale}{path}{caption}
  Places your figure at the spot where it's called, if possible. The command is file-format agnostic i.e. it works the same for both regular images and vector graphics. Scale is from 1% to 100% of the current column-width, i.e. from 0.01 to 1. Caption is optional.

These command names were chosen to ensure that the readability of the source code is minimally affected.

• \b{...} (b)old text.
• \c{...} (c)ode/mono inline.
• \i{...} (i)talic text.
• \l{...} (l)arge letter.
• \m{...} (m)ath inline.
• \s{...} (s)trikeout.
• \u{...} (u)nderline.

Add a strip of text to the top of each page.

• \header{left}{center}{right}

Add headings to the document.

• \h{...} Level one heading.
• \hh{...} Level two heading.
• \hhh{...} Level three heading.
• \hhhh{...} Level four heading.

Top-level headings will act like chapters in book-like classes, but as sections in article-like classes. Headings will be numbered, unless a * is added to the command, e.g. \h*{...}. The regular commands, like \chapter and \section can still be used along with their starred counterparts.

• \start{odd/even}
  Applicable to book-like classes only. It will instruct the compiler to add blank pages such that chapters always start on odd or even pages. In western bookbinding, it is traditional to have chapters start on odd (recto) pages. If this command is not used, no blank pages will be added.

In-class commands:

• addheadingseparator{type} will separate numbering from the actual heading with either a line or a final dot after the number.

Add an ISBN-code along with a corresponding barcode to your document. Should be called before \begin{document}.

• \isbn{978-0201529838}

Add a license to your document with an automatically generated copyright statement based on the input to the command. Should be called before \begin{document}.

• \license{type}{modifiers}{version}{holder}
  An overview of the possible inputs the command. E.g \license{CC}{by-nc-sa}{3.0}.
  The Copyright holder is optional.

  Types	Modifiers	Versions
  Creative Commons: CC	Attribution: by ShareAlike: sa NoDerivatives: nd NonCommercial: nc	Universal: 1.0 Unported: 3.0 International: 4.0

Add lists to your document. It is possible to nest lists.

\items{
    \item Something
    \item Another thing.
    \items*{
        \item Something else
        \item The final thing.
    }
}

items{...} will be numbered, and items*{...} will be bullet points.

Add math-blocks to your document.

\math{label}{
    % Regular latex math.
}

The label is required and the math block will be numbered. These are shortcut commands in the math environment:

• \mean{x} $\rightarrow \overline{x}$
• \Re $\rightarrow \mathbb{R}$ (Real set)
• \Im $\rightarrow \mathbb{I}$ (Imaginary set)
• \N $\rightarrow \mathbb{N}$ (Natural set)
• \Z $\rightarrow \mathbb{Z}$ (Integer set)
• \Q $\rightarrow \mathbb{Q}$ (Rational set)
• \C $\rightarrow \mathbb{C}$ (Complex set)
• \epsilon $\rightarrow \varepsilon$ (varepsilon)

If this bundle is loaded, it will automatically fill in the metadata fields of the pdf, like the title, subject, keywords etc.

Add various elements relating to documents that are periodicals, like a newspaper. Should be called before \begin{document}.

• \cost{\$9.99}
  Add a price tag.
• \issue{123}
  Add in issue number.
• \location{Copenhagen}
  Add a location specifier.
• \volume{123}
  Add a volume number.

Add various elements relating to documents that are published in book-form, like a novel. Should be called before \begin{document}.

• \dedicate{dedicatee}{message}
  Dedicate your document to someone, along with an optional message.
• \edition{123}{year}
  Specify the edition of the document and the year it was published.
• \note{longer author's note}
  Add an author's note.
• \publisher{your publishing company}
  Specify the publisher of your document.
• \thank{people or organizations}
  Thank someone in your document.
• \epigraph{poem or quotation}
  Add a short paragraph of informal text that suggests the theme of the book.
• \endpages{N}{M}
  Add N blank pages to the start and optionally M blank pages to the end of the document. This is mostly useful when printing and binding the document into a book.

In-class commands (for creating custom classes): \addFrontCover, \addBackCover, \addFormalPage, \addCorners, \addBorders, \addEpigraph, \addBlanks.

Add ornamental elements all pages of the document. Browse the types of ornaments are available in the documentation for the pgfornaments package. Check out the poem class for a visual example.

• \corners{ornament_id}{color!opacity}{width}{padding}
  Add ornaments to all four corners of all pages. Only the ID is mandatory.
• \borders{ornament_id}{color!opacity}{width}{padding}
  Add ornaments to all four sides of all pages. Only the ID is mandatory.

Reference internal elements and cite external sources from your bibliography.

• \at{label}
  Reference your figures, tables, math-blocks, headings, code-blocks, etc. using your own labels.
• \At{label}
  Uppercase equivalent of \r.
• \cite{your_source}
  As defined in your bibliography file.
• \bib{path/to/refs}{style}
  Specify and print your bibliography in a given style.
  Styles: abbrv, acm, alpha, apalike, ieeetr, plain, siam, unsrt
  Default to unsrt (in order of appearance).
  Do not include the .bib extension when specifying the path.
  Adding a * to the command, i.e. \bib*{...} will print the entire given bibliography, regardless of whether entries have been explicitly referenced in your document.

In-class commands:

• \bibfont{\...}
  Apply styling commands to the bibliography text.

Place signature fields in your document.

• sign{name}{designation}
  E.g. \sign{Nicklas Vraa}{CEO of the Universe}. To place multiple fields on the same line, don't leave a blank line between command calls.

These are commands for setting up the basic layout characteristics of your document. Should be called before \begin{document}.

• \size{standard}{orientation}
  Set the dimensions and orientation of your document by specifying standards. E.g \size{a4}{portrait}.

  ISO-A	ISO-B	ISO-C	ANSI	US	Orientation
  a0 a1 ... a6	b0 b1 ... b6	c0 c1 ... c6	ansia ansib ... ansie	letter executive legal	portrait landscape

  Alternatively, use \size{custom}{width}{height}, e.g. \size{custom}{6in}{9in}.
• \margins{top}{bot}{inner}{outer}
  Alternatively, the margins may be specified as {all}, {topbot}{innerouter}, {top}{bot}{innerouter}. When doing double-sided printing, the inner margin is often wider than the outer margin to allow for space to bind pages together. For single-sided printing and digital-only documents, the inner and outer margins are almost always equal.

There are three types. These three tables will cover 90% of your table-needs, but you have access to the full power of the tabularray package for more complicated tables. The & symbol separates items and \\ separates rows. Caption is optional.

\tabs{label}{type}{
    % Your table content.
}{caption}

Types:

• cols: Classic table, the top row acts as the header.
• rows: The left-most column acts as the header.
• grid: Both the top row and left-most column act as headers.

Formatting code for the table may also be given explicitly in the type field.