列出了采用Scala语言进行开发时的最佳实践建议，总共分为5大类：
①Hygienic Rules
②Language Rules
③Application Architecture
④Concurrency and Parallelism⑤Akka Actors。

Scala Best Practices

A collection of best practices, friendly to people that want to contribute.

• Version: 0.4
• Updated at: 2014-10-24

Table of Contents

• 0. Preface

  • 0.1 MUST NOT follow advice blindly
  </li>

• 1. Hygienic Rules

  • 1.1. SHOULD enforce a reasonable line length
  • 1.2. MUST NOT rely on a SBT or IDE plugin to do the formatting for you
  • 1.3. SHOULD break long functions
  • 1.4. MUST NOT introduce spelling errors in names and comments
  • 1.5. Names MUST be meaningful
  </ul> </li>

  • 2. Language Rules

    • 2.1. MUST NOT use "return"
    • 2.2. SHOULD use immutable data structures
    • 2.3. SHOULD NOT update a "var" using loops or conditions
    • 2.4. SHOULD NOT define useless traits
    • 2.5. MUST NOT use "var" inside a case class
    • 2.6. SHOULD NOT declare abstract val or var or lazy val members
    • 2.7. MUST NOT throw exceptions for validations of user input or flow control
    • 2.8. MUST NOT catch Throwable
    • 2.9. MUST NOT use "null"
    • 2.10. MUST NOT use "Option.get"
    • 2.11. MUST NOT use Java's Date or Calendar, instead use Joda-Time or JSR-310
    • 2.12. SHOULD NOT use Any or AnyRef or isInstanceOf / asInstanceOf
    • 2.13. MUST serialize dates as either Unix Timestamp or ISO 8601
    • 2.14. MUST NOT use magic values
    • 2.15. SHOULD NOT use "var" as shared state
    • 2.16. Public functions SHOULD have an explicit return type
    • 2.17. SHOULD NOT define case classes nested in other classes
    </ul> </li>

    • 3. Application Architecture

      • 3.1. SHOULD NOT use the Cake pattern
      • 3.2. MUST NOT put things in Play's Global
      • 3.3. SHOULD NOT apply optimizations without profiling
      • 3.4. SHOULD be mindful of the garbage collector
      </ul> </li>

      • 4. Concurrency and Parallelism

        • 4.1. SHOULD avoid concurrency like the plague it is
        • 4.2. SHOULD use appropriate abstractions only where suitable
        • 4.3. SHOULD NOT wrap purely CPU-bound operations in Futures
        • 4.4. MUST use Scala's BlockContext on blocking I/O
        • 4.5. SHOULD NOT block
        • 4.6. SHOULD use a separate thread-pool for blocking I/O
        • 4.7. All public APIs SHOULD BE thread-safe
        • 4.8. SHOULD avoid contention on shared reads
        • 4.9. MUST provide a clearly defined and documented protocol for each component or actor that communicates over async boundaries
        • 4.10. SHOULD always prefer single producer scenarios
        • 4.11. MUST NOT hard-code the thread-pool / execution context
        </ul> </li>

        • 5. Akka Actors

          • 5.1. SHOULD evolve the state of actors only in response to messages received from the outside
          • 5.2. SHOULD mutate state in actors only with "context.become"
          • 5.3. MUST NOT leak the internal state of an actor in asynchronous closures
          • 5.4. SHOULD do back-pressure
          </ul> </li> </ul>

          项目主页：http://www.open-open.com/lib/view/home/1414820091653