Mermaid diagram renderer for MoonBit (ASCII and SVG output)

mermaid

diagram

ascii

svg

flowchart

sequence

moon add mizchi/moomaid@0.4.0

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Author

mizchi

Version

0.4.0

License

Apache-2.0

Repository

github.com/mizchi/moomaid

Last updated

19 days ago

Downloads

Dependencies

README

#moomaid

Mermaid diagram renderer written in MoonBit. Outputs ASCII art or SVG.

#Install

# Native binary (Linux x64, macOS arm64)
curl -fsSL https://raw.githubusercontent.com/mizchi/moomaid/main/install.sh | sh

# npm
npx moomaid -h

# MoonBit CLI tool
moon install mizchi/moomaid/cmd/moomaid

# MoonBit library
moon add mizchi/moomaid

#CLI

# Render from file
moomaid diagram.mmd
moomaid --svg diagram.mmd

# Render from stdin
echo 'graph LR; A --> B' | moomaid -

# HTML output
moomaid --html diagram.mmd

# HTML demo page (all diagram types)
moomaid --html

#Options

--svg          Output SVG (default: ASCII)
--ascii        Output ASCII art
--kitty        Output Kitty graphics protocol
--html         Output HTML with embedded SVG
--width <n>    Max width for ASCII (default: 80)
               For kitty: image width in px (default: 640)
-              Read from stdin
--help         Show help

#Portable Skill API

cmd/skill is the Wasm-friendly command package for skills.mooncakes.io. It accepts Mermaid source from standard input and writes exactly one rendered artifact on success.

# Local Wasm package
moon runwasm src/cmd/skill --format ascii < diagram.mmd
moon runwasm src/cmd/skill --format svg < diagram.mmd
moon runwasm src/cmd/skill --format svg --debug-layout < diagram.mmd

# Standalone script prototype with the same contract
moon run --target wasm examples/moomaid.mbtx --format ascii < diagram.mmd

--format ascii|svg controls the artifact and defaults to ascii. For SVG, use --theme, --font, --padding, --background, --transparent, --title, and --description to control presentation and accessibility. --debug-layout adds flowchart diagnostics: node bounds are blue, edge-label bounds are green, subgraph headings are purple, edge paths are orange, and potential overlaps are highlighted in red. On invalid Mermaid input, the command writes a line and column diagnostic to standard error, leaves standard output empty, and exits with status 1. Invalid command-line arguments exit with status 2. After publishing, the same command is runnable by its Mooncakes coordinate: moon runwasm mizchi/moomaid/cmd/skill@<version> --format svg.

#Diagramming guidance for agents

skills/moomaid-diagramming is an agent skill for choosing a Mermaid diagram when explaining code or architecture. It covers component boundaries, runtime requests, type and data models, lifecycles, timelines, plans, and Git history, and includes rendering and presentation checks.

#Diagram Types

#Flowchart (graph LR / graph TD)

Use for visualizing data flow, module dependencies, and process graphs.

graph LR
  Input --> Process --> Output

graph TD
  Start[Start] --> Auth{Auth}
  Auth -->|pass| Load[Load Data]
  Auth -->|fail| Error[Error Page]
  Load --> Validate{Validate}
  Validate -->|ok| Process[Process]
  Validate -->|ng| Error
  Process --> Save[Save]
  Save --> Done[Done]
  Error --> Done

subgraph ... end によるグループ化にも対応しています。

flowchart TD
  Client --> API
  subgraph backend[Backend]
    API --> DB
  end

#Sequence Diagram (sequenceDiagram)

Use for describing layer boundaries and API call flows.

sequenceDiagram
  participant Browser
  participant API
  participant Auth
  participant DB
  Browser->>API: POST /login
  API->>Auth: Validate token
  Auth-->>API: OK
  API->>DB: SELECT user
  DB-->>API: User data
  API-->>Browser: 200 JSON

参加者の別名、autonumber、note、activation、loop / alt / opt / par / break の制御ブロックを扱えます。拡張構文のASCII出力は、可搬性を優先したイベントストリーム形式です。

#Other supported types

stateDiagram-v2 - State machine diagrams
classDiagram - Class diagrams
erDiagram - Entity relationship diagrams
timeline - Chronological event outlines
gitGraph - Branch, checkout, commit, and merge histories
gantt - Sections and task start/duration tables
mindmap - Indented architecture and idea outlines
journey - Sections and user/system journey tasks
pie - Labeled proportion outlines

#Library Usage

// ASCII output
let ascii = @moomaid.render_to_string("graph LR\n  A --> B")

// ASCII with options
let options : @moomaid.Options = {
  use_ascii: false,
  padding_x: 2,
  padding_y: 1,
  box_border_padding: 1,
  max_width: 80,
}
let ascii2 = @moomaid.render_to_string("graph LR\n  A --> B", options~)

// SVG output (experimental)
let svg = @moomaid.experimental_render_to_svg("graph LR\n  A --> B")

// Portable Skill API
let skill_svg = @moomaid.render(
  "graph LR\n  A --> B",
  @moomaid.OutputFormat::Svg,
)

#TUI Viewer

Interactive terminal viewer with tab switching and Kitty graphics protocol support.

just tui

Tab / Shift+Tab: Switch diagrams
Up / Down: Scroll
s: Toggle ASCII / SVG mode (Kitty-compatible terminals)
q: Quit

#License

Apache-2.0

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