2nd/10_Wiki/Dev/Topic_PHP/PHP_Namespaces.md

id, title, category, status, verification_status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, created_at, updated_at, review_reason, merge_history, tags, raw_sources, applied_in, github_commit

id	title	category	status	verification_status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	created_at	updated_at	review_reason	merge_history	tags	raw_sources	applied_in	github_commit
php-namespaces	PHP Namespaces	Programming_Language	draft	conceptual		namespace keyword PHP 네임스페이스		B	0.9	2026-07-04	2026-07-04			php programming w3schools namespaces	https://www.w3schools.com/php/php_namespaces.asp

PHP Namespaces

🎯 한 줄 통찰 (One-line insight)

namespace MUST be the very first statement in a PHP file — even a preceding echo "Hello World!"; before the namespace declaration is explicitly shown as INVALID code, meaning nothing (not even innocuous output) can come before it. [S1]

🧠 핵심 개념 (Core concepts)

• Namespace — groups classes/interfaces/functions/constants under a name to prevent naming collisions (e.g., two unrelated Table classes — one for HTML, one for furniture). [S1]
• Must be declared first — namespace Html; must be the absolute first line of the file. [S1]
• Nested namespaces — namespace Code\Html; for further organization. [S1]
• Accessing from outside the namespace — requires the full qualifier: new Html\Table();. [S1]
• Inside the namespace — no qualifier needed (new Table();) once you've declared namespace Html; at the top. [S1]
• use ... as ... — creates an alias for a namespace or class, shortening repeated references. [S1]

📖 세부 내용 (Details)

• Declaring and using within a namespace: namespace Html; class Table { ... } $table = new \Html\Table();. [S1]
• Accessing from outside: $table = new Html\Table(); $row = new Html\Row();. [S1]
• Accessing after declaring the same namespace: namespace Html; $table = new Table(); $row = new Row();. [S1]
• Namespace alias: use Html as H; $table = new H\Table();. [S1]
• Class alias: use Html\Table as T; $table = new T();. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 네임스페이스 선언 위치의 절대적 제약: echo 문 하나라도 namespace 선언보다 앞에 오면 무효한 코드가 된다는 점이 명시적으로 경고됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — HTML용 Table 클래스와 가구용 Table 클래스를 네임스페이스로 분리하는 것이 이름 충돌 방지의 대표 사례다. [S1]

💻 코드 패턴 (Code patterns)

Namespace must be the first statement in the file (PHP):

<?php
namespace Html; // must be the very first line
class Table {
    public $title = "";
    public $rows = 0;
}

✅ 검증 상태 및 신뢰도

• 상태: draft
• 검증 단계: conceptual
• 출처 신뢰도: B (W3Schools — widely used educational reference, not a primary standards body)
• 신뢰 점수: 0.90
• 중복 검사 결과: 신규 생성 (New discovery)

🔗 지식 그래프 (Knowledge Graph)

• 상위/루트: PHP Tutorial
• 관련 개념: PHP OOP Static Properties, PHP Iterables
• 참조 맥락: 이름 충돌 방지를 위한 그룹화 — 이터러블(Iterables) 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — PHP Namespaces — https://www.w3schools.com/php/php_namespaces.asp

📝 변경 이력 (Change history)

• 2026-07-04: Initial draft synthesized from the W3Schools "PHP Namespaces" page (Astra wiki-curation, P-Reinforce v3.1 format).