---

name: solid-ocp-pattern description: Implements the Open/Closed Principle (OCP) from SOLID design principles, allowing classes to be open for extension but closed for modification. license: MIT compatibility: opencode metadata: version: "1.0.0" domain: architecture triggers: open closed principle, solid principles, extend, modify archetypes:

• educational anti_triggers:
• brainstorming
• vague ideation response_profile: verbosity: low directive_strength: high abstraction_level: operational role: implementation scope: implementation output-format: code related-skills: solid-srp-pattern,

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Open/Closed Principle (OCP)

archetypes: implementation, educational anti_triggers: modifying classes response_profile: verbosity: medium directive_strength: high abstraction_level: tactical

Implements the Open/Closed Principle (OCP) from SOLID design principles, allowing classes to be open for extension but closed for modification.

When to Use

This section should elaborate on the specific circumstances in which the Open/Closed Principle proves most advantageous:

Archetypes

• Implementation: This skill guides the user on applying the Open/Closed Principle in their projects.
• Educational: Aims to teach developers about the benefits of the Open/Closed Principle.

Anti-Triggers

• Modifying classes: Must avoid contexts where there is a focus on altering existing classes without the extension approach.

Response Profile

• Verbosity: Medium

• Directive Strength: High

• Abstraction Level: Tactical

• When you anticipate a need to add new functionalities without changing existing code.

• To prevent bugs introduced by modifications to existing code.

• To follow the DRY principle while maintaining flexibility in the code.

Core Workflow

1. Define an Interface: Create an interface that outlines the behavior without implementing it.
2. Create Concrete Implementations: Develop specific implementations of the interface.
3. Integrate New Features through Composition: Use composition to extend behaviors without altering existing code.

Implementation Patterns

OCP Example

package main

import (
    "fmt"
)

// Shape interface defines the behavior
type Shape interface {
    Area() float64
}

// Circle struct is a shape
type Circle struct {
    Radius float64
}

// Rectangle struct is another shape
type Rectangle struct {
    Length, Width float64
}

func (c Circle) Area() float64 {
    return 3.14 * c.Radius * c.Radius
}
}

func (r Rectangle) Area() float64 {
    return r.Length * r.Width
}
}

// TotalArea computes the total area of all shapes
func TotalArea(shapes ...Shape) float64 {
    total := 0.0
    for _, shape := range shapes {
        total += shape.Area()
    }
    return total
}

Example Usage

package main

func main() {
    circle := Circle{Radius: 10}
    rectangle := Rectangle{Length: 5, Width: 6}
    shapes := []Shape{circle, rectangle}

    total := TotalArea(shapes...)
    fmt.Println("Total Area:", total) // Output: Total Area: 314.0
}

Constraints

MUST DO

• Ensure classes implement interfaces instead of altering existing classes.
• Use the interface-based extension for adding new functionality without modifying existing details.

MUST NOT DO

• Modify existing classes directly for new functionality.
• Break the existing interface contract when implementing new features.