document

Original source / Raw SKILL.md

---
name: document
description: Documentation style guide and rules for creating documentation
---

# Document Rules

Documentation style varies by type. Follow these principles for consistency.

## Specification Documents (`docs/specification/`)

**Purpose:** Formal mathematical reference for constitutions, geometries, and core concepts.

**Rules:**
- Use LaTeX math (`$$` for display, `$` for inline) extensively
- Define all variables after formulas
- Prefer math over code examples
- Structure: Definition → State Variables → Formulations → Energy Functions
- Use numbered sections: `## #12 Hookean Spring`
- Reference academic papers when applicable
- Include parameter ranges: "$100MPa \le \kappa \le 100GPa$"
- Explain notation: "where $\|\cdot\|_F$ is the Frobenius norm"
- Cross-reference: `[link text](./file.md)`
- Include diagrams (SVG): `![Description](./media/figure.svg)`

**Example:**
```markdown
# Hookean Spring

**Hookean Spring** is a constitutive model for simulating linear elastic springs.

## #12 Hookean Spring

$$
E = \frac{\kappa}{2} \epsilon^2 = \frac{\kappa}{2} \left(\frac{L - L_0}{L_0}\right)^2
$$

where:
- $\kappa$ is the spring constant
- $L_0$ is the rest length
```

## Tutorial Documents (`docs/tutorial/`)

**Purpose:** User-friendly guides with code examples.

**Rules:**
- Always provide both C++ and Python using tabs:
  ```markdown
  === "C++"
      \`\`\`cpp
      // code
      \`\`\`
  === "Python"
      \`\`\`python
      # code
      \`\`\`
  ```
- Include complete, runnable examples with imports
- Start high-level, progress to details
- Use diagrams: `![description](./media/file.svg)`
- Include step-by-step workflows
- Use tables for structured data

**Example:**
```markdown
=== "C++"
    \`\`\`cpp
    using namespace uipc::core;
    Scene scene;
    \`\`\`
=== "Python"
    \`\`\`python
    from uipc.core import *
    scene = Scene()
    \`\`\`
```

## Reference Documents (`docs/specification/*_uid.md`)

**Purpose:** Technical reference for identifiers and ranges.

**Rules:**
- Define identifier ranges clearly
- Distinguish official vs. user-defined ranges
- List all official identifiers
- Cross-reference to detailed specs

**Example:**
```markdown
# Constitution UID

64-bit unsigned integer. Official range: $[0, 2^{32}-1]$. User-defined: $[2^{32}, 2^{64}-1]$.
```

## Build/Install Documents (`docs/build_install/`)

**Purpose:** Step-by-step build instructions.

**Rules:**
- Use prerequisites table with versions and links
- Number steps clearly
- Include verification commands
- Use shell tags: `shell`, `bash`, `powershell`
- Show copy-pasteable commands

**Example:**
```markdown
| Name | Version | Usage | Import |
|------|---------|-------|--------|
| [CMake](https://cmake.org/) | >=3.26 | build system | system install |

\`\`\`shell
git clone https://github.com/microsoft/vcpkg.git
\`\`\`
```

## General Rules

- **Math:** `$$` for display, `$` for inline. Define variables after formulas. Use bold for vectors: $\mathbf{x}$
- **Code:** Appropriate language tags. Complete, runnable examples. C++/Python tabs in tutorials
- **Links:** Relative paths `[text](./file.md)`. Link to related docs and external resources
- **Media:** Store in `media/` subdirectories. Use SVG. Reference: `![Description](./media/file.svg)`
- **Tables:** Markdown tables with headers for structured data
- **Headers:** `#` title, `##` sections, `###` subsections

## Checklist

- [ ] Formulas use LaTeX, variables defined
- [ ] Code examples complete and runnable
- [ ] Cross-references use relative paths
- [ ] Images exist and are referenced
- [ ] Tables formatted correctly
- [ ] Document type principles followed
- [ ] No ambiguity in technical descriptions