About CalcMark Lark

Lark is a live playground for CalcMark — a calculation-oriented markup language that blends prose and math in one document.

Two modes

Lark automatically detects which mode to use based on your input:

• CalcMark (.cm) — the entire document is a single CalcMark program. Variables, frontmatter (@locale, exchange rates, @scale), and markdown prose all share one scope. Define something at the top, reference it anywhere below. Best for focused calculations like budgets, cost models, and unit conversions.
• Markdown (.md) — a standard Markdown document with CalcMark fenced code blocks (```cm or ```calcmark). The prose renders as rich HTML. Each CalcMark block is evaluated independently — variables from one block are not visible in another. Best for reports and articles where calculations are embedded in longer prose. Detected automatically when your input contains these fences.

Sharing

Click Share to copy a URL containing your entire document, compressed into the URL fragment. No server storage — the document lives in the link. Documents over ~2KB may be too large to share this way; use the copy button instead.

Output formats

Use the output dropdown to switch between Preview (rendered HTML), raw HTML source, Markdown, plain Text, or JSON. In Markdown mode, Text and JSON are not available.

CLI

CalcMark has a command-line tool, cm. Visit calcmark.org for install instructions.

cm convert budget.cm --to html        # CalcMark to HTML
cm convert report.md --embedded        # Markdown with CalcMark blocks
cm watch budget.cm                     # Live preview in browser
cm watch report.md                     # Embedded mode live preview

Links

• calcmark.org — language documentation
• Docs — user guide and reference
• go-calcmark — interpreter and CLI
• calcmark-lark — this web app (source)