# PHP Language Standards

> Core PHP language standards and modern 8.x features.

- Skill: `mte90/php-language-standards` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add mte90/php-language-standards`
- Raw SKILL.md: https://api.skillmd.com/api/skills/mte90/php-language-standards/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: mte90 (https://skillmd.com/u/mte90)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/mte90/php-language-standards

---


# PHP Language Standards

## **Priority: P0 (CRITICAL)**

## Structure

```text
src/
└── {Namespace}/
    └── {Class}.php
```

## Implementation Guidelines

- **Strict Typing**: Declare `declare(strict_types=1);` at file top.
- **Type Hinting**: Apply scalar hints and return types to all members.
- **Modern Types**: Use Union (`string|int`) and Intersection types.
- **Read-only**: Use `readonly` for immutable properties.
- **Constructor Promotion**: Combine declaration and assignment in `__construct`.
- **Match Expressions**: Prefer `match` over `switch` for value returns.
- **Named Arguments**: Use for readability in optional parameters.

## Anti-Patterns

- **No Type Context**: Avoid functions without return or parameter types.
- **Sloppy Comparison**: **No ==**: Use `===` for strict comparison.
- **Legacy Syntax**: **No switch**: Use `match` for simple value mapping.
- **Global Scope**: **No Globals**: Never define logic in global namespace.

## References

- [Modern PHP Patterns](references/implementation.md)