Ground Extensibility

Skill: Extensibility

"Making code more flexible results in less maintenance."

The Standard

• Manager/Driver: For services with multiple implementations. Users register custom drivers via extend() without touching core code.
• Adapter/Interface: For framework-agnostic cores. Define a finite interface; each backend implements it. The interface IS the extension point.
• Plugin System: For platforms hosting third-party code. A contract with register() and boot() lets plugins wire into the host.
• Config-Driven Bindings: Implementations specified in config, bound to interfaces in the provider. One config line swaps the class.
• Static Callbacks: Accept closures for targeted customization points. The package stores the closure, calls it at the right time.
• Events: Fire events at key moments. The listener is the user's code. Zero coupling.
• Macroable: Add the trait so users can extend your classes at runtime without subclassing.
• Protected Over Private: protected is an invitation. private is a wall. Make extension possible by default.

The Check

Ask yourself:

• Can a user customize this without forking?
• Does the mechanism match the scale? Config for swaps, Manager for drivers, Plugin for platforms.
• Does every meaningful behavior have a seam?
• Are you adding config options when a model swap would solve it?

See also: craft-extension-point (implementation patterns for each mechanism).

Real-World Examples

See examples.md.