Go Idioms

The "Accept Interfaces, Return Structs" idiom means your function parameters should be interfaces to allow flexibility, while your return values should be concrete structs to maintain stability.

// Accept interface (flexible input)
func Process(r io.Reader) error {
    // ... implementation
}

// Return struct (stable output)
func GetConfig() Config {
    return Config{Timeout: 30}
}

This pattern prevents callers from needing to know implementation details when calling your function, while ensuring your function's output contract doesn't change unexpectedly.

Go Idioms: Accept Interfaces, Return Structs is a design rule for writing flexible Go code. You accept interfaces as inputs so callers can pass any compatible type, but you return specific structs so users know exactly what data they get back. Think of it like a restaurant: you accept any payment method (interface) but always give you the same type of receipt (struct).