While I love Mermaid, but sometimes its syntax feels a bit heavy for quick diagrams. Arrowscript is my attempt to build a fast, minimal diagram language with a near-zero learning curve. It’s useful for sketching out ideas in plain text and supports the most common diagram types with a single, unified syntax.

diagram: flow

start = "Start"
check = "Check input"
fix = "Fix issue"
done = "Finish"

start -> check : begin
check -> fix : invalid [danger]
check -> done : valid [success]
fix -> check : retry [loop]

diagram: sequence

agent = "Support Agent"
system = "System"

user -> agent : "I need help"
agent -> system : "Fetch logs" [info]
system -> agent : "Logs sent" [success]
agent -> user : "Issue fixed" [success]

diagram: tree

root = "Project"
design = "Design"
dev = "Development"
test = "Testing"

root -> design
root -> dev
dev -> test : next [info]

• Learn by building
• Minimal syntax, instant rendering
• PEG-based grammar shared across Go and TypeScript
• VSCode plugin with live diagram preview
• LSP support, syntax highlighting, and error reporting
• Export to SVG, PNG, ASCII
• Web playground with editor and live preview

This is very much a work in progress. The grammar is defined and the parsers have been generated. Next steps are:

• Test the parsers.
• Build full flow from grammar to parser to AST to renderer.
• Create the web playground.
• Create the VSCode plugin.

If Arrowscript sounds useful or fun, feel free to jump in! Help is welcome, whether with rendering, UI, testing, docs, or ideas.