FastLED WASM Python Development

Development rules for the FastLED WASM project, ensuring consistent Python execution with uv and cross-platform emoji handling.

Overview

This skill enforces critical development practices for the FastLED WASM project:

Instructions

1. Python Command Execution

**CRITICAL: Always use `uv` to run Python code, never `python` or `python3` directly.**

When executing Python code or scripts:

Examples:

Rationale:

2. Emoji and Unicode Handling

**CRITICAL: Always use the `EMO()` function for emojis, never hardcode emojis directly.**

When adding user-facing messages with emojis:

Common emoji patterns:

Example:

```python

from fastled.emoji_util import EMO

print(f"{EMO('⚠️', 'WARNING:')} Debug mode detected")

```

Rationale:

3. Development Workflow

When writing or reviewing code:

1. Prefix all Python commands with `uv run`

2. Use `bash test` for unit tests (per project convention)

3. Install dependencies with `uv add <package>`

4. Update existing scripts using `python`/`python3` to use `uv run`

5. Wrap all emoji output with `EMO()` function

4. Documentation and Scripts

When creating documentation or shell scripts:

Constraints

Examples

Bad Practices

```python

❌ Direct python execution

python src/fastled/cli.py

❌ Hardcoded emoji

print("⚠️ Warning: Something went wrong")

```

Good Practices

```python

✅ Using uv

uv run src/fastled/cli.py

✅ Using EMO function

from fastled.emoji_util import EMO

print(f"{EMO('⚠️', 'WARNING:')} Something went wrong")

```