Swift Language Standards

Priority: P0

Implementation Guidelines

Optionals & Safety

• Never Force Unwrap: Use guard let, if let, or nil coalescing (??).
• Nil Comparison: Use value != nil instead of if let _ = value.
• Implicitly Unwrapped: Avoid Type!. Use proper Type?.

Protocols & Extensions

• Protocol Composition: Prefer struct + protocols over class inheritance.
• Extensions: Use for conformance (extension MyType: Codable), not storage.
• Protocol Witnesses: Explicitly implement all required members.

Type Safety

• Avoid Any: Use generics or associated types instead.
• Enums: Prefer enums with associated values over multiple Optionals.
• Value Types: Default to struct unless reference semantics needed.

Anti-Patterns

• Force Unwrapping: **No ! operator**: Use safe unwrapping.
• Sentinel Values: **No -1 for failure**: Use Optional.
• as! Casting: **No Force Cast**: Use conditional cast (as?).

References

• Optionals & Protocols