MathDown

A computational Markdown editor for macOS and iOS.

macOS Desktop Background
MathDown on macOS

Just the facts.

MathDown is a text editor designed for scientists, engineers, and students who need to write about math and see it work in real-time. It combines standard Markdown with a powerful evaluation engine.

MathDown on iPad
MathDown on iPhone

Core Capabilities

  • Rich LaTeX Rendering High-fidelity rendering of math expressions using standard LaTeX syntax.
  • Live Evaluation Variables and functions are evaluated as you type. No compilation step.
  • REPL Mode Use $$$ blocks for interactive scratchpad behavior. Define functions, expand terms, and see step-by-step simplifications.
  • Syntax Highlighting Deep integration with the AST to provide accurate highlighting for both Markdown and Math.

Competition

Feature MathDown Typora MacDown
Live Eval Yes No No
REPL Blocks Yes No No
LaTeX Rich Rich Basic
Cross-Platform macOS/iOS Desktop macOS

Technical Details

Evaluation System

The evaluation engine uses a custom visitor pattern to traverse the math AST. It supports:

  • Expression simplification
  • Variable substitution
  • Function distribution (e.g., /expand)

Demo: REPL Behavior

$$$ let f(x) = (x + 1)^2 /expand f(x) # Output: x^2 + 2x + 1 f(3) # Output: 16 $$$
MathDown on iPhone Landscape

Availability

Available for macOS and iOS.