LitTex is an archival markup language that renders to both LaTeX and HTML.

It was designed by N. C. Landolfi for the Litterae and Bourbaki projects.

Here is an example, from Section 1 of Halmos’ Naive Set Theory.

      ¶ ⦊
        ‖ The principal concept of set theory, the one that in
          completely axiomatic studies is the principle primitive
          (undefined) concept, is that of ‹belonging›. ⦉

        ‖ If $x$ belongs to $A$ ($x$ is an element of $A$, $x$
          is contained in $A$), we shall write
          ◇ ⦊
            ‖ x ∈ A. ⦉
          ⦉⦉

        ‖ This version of the Greek letter epsilon is so often
          used to denote belonging that its use to denote
          anything else is almost prohibited. ⦉

        ‖ Most authors relegate $ϵ$ to its set-theoretic use
          forever and use $ε$ when they need the fifth letter of
          the Greek alphabet. ⦉
      ⦉

LitTex is readable, short, and has math.

What can LitTex render? Well, this page, for instance.

Closing elements

Closing elements are denoted by ⦉. See examples below.

Runs

Runs are denoted by ‖.

Example 1

      ‖ This is a run. ⦉

      ‖ The fun part is that runs can be multiple lines of
        plain unicode text 🙂, but the lit program will format
        them, and have them wrap nicely (in fact, it formatted
        this block you are reading). ⦉

Footnotes

Footnotes are denoted by †.

Example 1: Kierkegaard’s Journal

      ¶ ⦊
        ‖ What I really need is to get clear about what I must
          do,
          † ⦊
            ‖ How often, when a person believes that he has the
              best grip on himself, it turns out that he has
              embraced a cloud instead of Juno. ⦉
          ⦉
          not what I must know, except insofar as knowledge must
          precede every act. ⦉

        ‖ What matters is to find a purpose, to see what it
          really is that God wills that ‹I› shall do; the
          crucial thing is to find a truth which is truth ‹for
          me›,
          † ⦊
            ‖ Only then does one have an inner experience, but
              how many experience life’s different impressions the
              way the sea sketches figures in the sand and then
              promptly erases them without a trace. ⦉
          ⦉
          to find ‹the idea for which I am willing to live and
          die›. ⦉
      ⦉

Display math blocks

Display math blocks are denoted by ◇.

Example 1:

      ◇ ⦊
        ‖ ∫ f dμ = ∫ f^+ dμ - ∫ f^- dμ. ⦉
      ⦉

      ◇ ⦊
        ‖ (X, ℱ, 𝗣) ⦉
      ⦉

Paragraphs

Paragraphs are denoted by ¶.

Example 1:

      ¶ ⦊
        ‖ Here it is. ⦉

        ‖ You can put math
          ◇ ⦊
            ‖ x^2 + y^2 = 1 ⦉
          ⦉
          where it ought to go. ⦉
      ⦉

List items

List items are denoted by ‣. See examples below.

Unordered lists

Unordered lists are denoted by ⁝.

Example 1

      ⁝ ⦊
        ‣ apples ⦉

        ‣ oranges ⦉

        ‣ and something more complicated
          ◇ ⦊
            ‖ ax^2 + bx + c = 0 ⦉
          ⦉⦉
      ⦉

Ordered lists

Ordered lists are denoted by 𝍫.

Example 1

      𝍫 ⦊
        ‣ did you know ⦉

        ‣ you can escape these \‖ \⦉ ⦉
      ⦉

Sections

Sections are denoted by §

Example 0

      § This is a section. ⦉

      §§ This is a subsection. ⦉

      §§§ This is a subsubsection. ⦉

      #§ This one is numbered ⦉

      #§§ And this one ⦉

Example 1

      § Why ⦉
      ¶ ⦊
        ‖ It happens that all circulant matrices have the same
          eigenvectors. ⦉
      ⦉

      § Definition ⦉
      ¶ ⦊
        ‖ Recall that if $C$ is circulant then
          ◇ ⦊
            ‖ C = c_0I + c_1 S + c_2S^2 + ⋯ + c_{n-1}S^{n-1}. ⦉
          ⦉⦉

        ‖ So $q ∈ 𝗥^d$ is an eigenvector of $C$ if and only
          if it is one of $S$.
          † ⦊
            ‖ Future editions will complete this development. ⦉
          ⦉⦉
      ⦉

Example 2.

      § Definition ⦉
      ¶ ⦊
        ‖ Let $(X, 𝗙)$ be a vector space where $𝗙$ is the
          field of real numbers or the field of complex numbers. ⦉

        ‖ The functional $f: X → 𝗥$ is a ❬norm❭ if
          𝍫 ⦊
            ‣ $f(v) ≥ 0$ for all $x ∈ V$ ⦉

            ‣ $f(v) = 0$ if and only if $x = 0 ∈ X$. ⦉

            ‣ $f(α x) = \abs{α}f(x)$ for all $α ∈ 𝗙$, $x ∈ X$ ⦉

            ‣ $f(x + y) ≤ f(x) + f(y)$ for all $x, y ∈ X$. ⦉
          ⦉⦉
      ⦉