# functional

> Functional programming patterns with pure functions, immutable state, and composition utilities

- Author: Claude Assistant
- Repository: mfethe1/skills
- Version: 20260123221508
- Stars: 0
- Forks: 0
- Last Updated: 2026-02-06
- Source: https://github.com/mfethe1/skills
- Web: https://mule.run/skillshub/@@mfethe1/skills~functional:20260123221508

---

---
name: functional
description: Functional programming patterns with pure functions, immutable state, and composition utilities
triggers:
  - functional
  - immutable
  - pure function
  - fp
  - compose
---

# Functional Programming

> Pure functions and immutable state.

## Instructions
1.  **Immutability**: Do not mutate data. Return new copies.
2.  **Purity**: Functions should have no side effects and return same output for same input.
3.  **Composition**: Build complex logic by composing small, simple functions.
4.  **Higher-Order Functions**: Use `map`, `filter`, `reduce` instead of loops.

## Verification

### Verification Workflow
Ensure skill outputs are correct and complete:

1. **Pre-Execution**
   - Verify prerequisites are met
   - Validate inputs and parameters
   - Confirm environment is ready

2. **During Execution**
   - Monitor for errors or warnings
   - Verify intermediate outputs
   - Check progress against expectations

3. **Post-Execution**
   - Validate final outputs
   - Verify success criteria met
   - Document any issues encountered

### Verification Checklist
- [ ] All inputs validated
- [ ] Execution completed without errors
- [ ] Output meets requirements
- [ ] Quality standards satisfied

### Failure Recovery
If verification fails:
1. Identify failure point
2. Document error context
3. Attempt remediation (max 3 attempts)
4. Escalate if unresolved