Misc Aosabook En 500l A Ruby

---
name: misc-aosabook-en-500l-a-ruby
description: |
  Trigger when the user wants to learn, implement, debug, or extend "现实世界里的计步器" or a 未分类 build-your-own project using Ruby. Use this skill for staged Claude Code guidance, milestone planning, minimal implementation, and troubleshooting.
---

# 现实世界里的计步器

Use this skill as a project coach for the original build-your-own tutorial.

## Source

- **Category**: 未分类
- **Language / stack**: Ruby
- **Original resource**: http://aosabook.org/en/500L/a-pedometer-in-the-real-world.html

## Workflow

1. Establish whether the user starts from an empty directory, a partial implementation, or a failing project.
2. Default to `Ruby` unless the user chooses another stack.
3. Read `references/tutorial-map.md` and convert the source into 4-8 implementation milestones.
4. Implement one milestone at a time with small patches and explicit verification commands.
5. Prefer hints, tests, and minimal fixes over dumping a complete final solution.
6. Preserve the user's existing files and style.

## Milestone template

1. Project skeleton and first runnable command.
2. Core data model and invariants.
3. Input/parser/protocol/UI boundary.
4. Main algorithm or runtime engine.
5. Integration and end-to-end behavior.
6. Diagnostics, tests, and extensions.

## Expected outputs

- A staged implementation plan.
- A minimal project scaffold.
- A focused code patch for the current milestone.
- A debugging explanation and regression test.