_index.md

title	Embedded Datacenter Cost
summary	CalcMark's embedded mode: live calculations inside a standard Markdown file, designed for Hugo and static-site pipelines.
weight	95
calcmark_source	testdata/examples/embedded-datacenter-cost.md

This example demonstrates embedded mode — CalcMark blocks inside a standard Markdown file. Instead of writing a .cm document, you write normal Markdown and tag calculation blocks with ```cm or ```calcmark. Each block is evaluated independently, and the results replace the original block. Everything else passes through unchanged.

The complete Markdown file is available at {{< repo-file path="testdata/examples/embedded-datacenter-cost.md" >}}.

---

How It Works

Run cm convert --embedded on any .md file:

cm convert report.md --embedded            # stdout
cm convert report.md --embedded -o out.md  # file

CalcMark scans for ```cm and ```calcmark fenced code blocks, evaluates each one as a self-contained CalcMark document, and replaces it with the evaluated Markdown output. Hugo frontmatter, footnotes, tables, HTML — everything else is byte-for-byte unchanged.

---

Block Independence

Each block is its own CalcMark document. Variables don't carry between blocks. This means you can reuse variable names and each block can have its own frontmatter:

```cm
servers = 12
cost_per_server = 450 USD
monthly_server_cost = servers * cost_per_server
```

Some prose in between...

```cm
---
exchange:
  EUR_USD: 1.09
---
eu_cooling = €45000
cooling_usd = eu_cooling in USD
```

The first block knows nothing about eu_cooling, and the second block knows nothing about servers. Each stands alone.

---

Block Frontmatter vs. Document Frontmatter

The file's YAML frontmatter (title, date, tags) belongs to Hugo — CalcMark never touches it. CalcMark frontmatter (exchange, scale, convert_to) goes inside each block:

---
title: "My Blog Post"      ← Hugo's — passed through unchanged
date: 2026-03-18
---

# My Post

```cm
---
scale:                      ← CalcMark's — applies to this block only
  factor: 1000
  unit_categories: [Currency]
---
capex = $875000
opex = $75000
build_tco = capex + (opex * 3)
```

With scale applied, the block above shows $875M capex and $1.1B TCO — modeling a fleet of 1,000 facilities.

---

Error Handling

If a block has an error (undefined variable, syntax error), CalcMark replaces it with an inline error blockquote and continues processing the rest of the document:

> **CalcMark Error:** line 1: undefined_variable: undefined variable "x" (line 42)

The exit code is 1 if any block had errors, but output is always produced. This means your build pipeline can detect problems without blocking the entire site build.

---

Fence Variants

CalcMark recognizes all CommonMark fence styles:

Fence	Accepted?
```cm	Yes
```calcmark	Yes
~~~cm	Yes
~~~calcmark	Yes
```cm {.highlight}	Yes (extra attributes OK)
```python	No — passed through unchanged
```cmake	No — cmake is not cm

---

Pipeline Integration

Embedded mode is designed for static-site build pipelines — like D2 for diagrams, but for calculations. Wire it into your Hugo build:

# Process all .md files with embedded CalcMark blocks
for f in content/posts/*.md; do
  cm convert "$f" --embedded -o "processed/$(basename "$f")"
done

# Or use it as a single-file preprocessor
cm convert content/cost-analysis.md --embedded -o content/cost-analysis.md

---

Features Demonstrated

• Embedded mode — ```cm and ```calcmark blocks inside standard Markdown
• Block independence — no shared state between blocks
• Block frontmatter — exchange rates and scale directives per-block
• Currency conversion — EUR→USD, GBP→USD via in keyword
• Growth functions — compound, depreciate, grow
• Scale directive — fleet-level modeling with unit_categories
• Error tolerance — inline error blockquotes, non-zero exit code

---

Try It

{{< repo-file path="testdata/examples/embedded-datacenter-cost.md" >}}

cm convert testdata/examples/embedded-datacenter-cost.md --embedded