SKILL.md
Backend Development
You are an expert in backend development with C++ and Elixir/Phoenix.
C++ Development
Naming Conventions
- Use PascalCase for classes and structs
- Use camelCase for variables and methods
- Use SCREAMING_SNAKE_CASE for constants and macros
Memory Management
- Prefer smart pointers (
std::unique_ptr,std::shared_ptr) over raw pointers
- Use
std::unique_ptrfor exclusive ownership
- Use
std::shared_ptronly when shared ownership is required
- Implement RAII for all resource management
- Avoid unnecessary heap allocations
Modern C++ Features
- Use
autofor type inference where it improves readability
- Leverage range-based for loops
- Use
std::optionalfor values that may not exist
- Use
std::variantfor type-safe unions
- Apply structured bindings for cleaner code
- Use
std::movefor move semantics
Error Handling
- Use exceptions for error handling
- Define custom exception types for domain-specific errors
- Catch exceptions at appropriate boundaries
- Ensure exception safety in all code
Best Practices
- Enforce const-correctness throughout
- Avoid C-style casts; use
static_cast,dynamic_cast, etc.
- Write unit tests with Google Test or Catch2
- Document with Doxygen comments
Elixir and Phoenix Best Practices
Core Philosophy
- Follow domain-driven design with PragDave philosophy
- Use functional programming with explicit error handling
- Embrace the "let it crash" principle
Code Organization
- Organize code around business domains using Phoenix contexts
- Keep contexts focused on single domains
- Use bounded contexts to prevent coupling
- Implement clear public APIs for each context
Pattern Matching and Control Flow
- Use pattern matching extensively for data extraction
- Apply "railway-oriented programming" with
withstatements
- Chain operations cleanly with the pipe operator
- Handle all pattern match cases explicitly
Error Handling
- Return tagged tuples (
{:ok, result}or{:error, reason})
- Use
withstatements to chain fallible operations
- Implement proper supervision trees
- Handle expected errors explicitly
Phoenix Contexts
- Group related functionality in contexts
- Define clear boundaries between contexts
- Use contexts as the API layer for business logic
- Keep controllers thin, delegate to contexts
LiveView
- Use LiveView as primary UI technology
- Implement function components for reusable UI
- Handle events in LiveView modules
- Manage state appropriately in assigns
Data Validation
- Validate at boundaries using
Ecto.Changeset
- Use changesets even outside database contexts
- Define clear validation rules
- Return helpful error messages