2nd/10_Wiki/Topics/Domain_Programming/Topic_PHP/PHP_Syntax.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-syntax	PHP Syntax	Programming_Language	draft	conceptual		PHP 기본 문법		B	0.9	2026-07-04	2026-07-04			php programming w3schools syntax	https://www.w3schools.com/php/php_syntax.asp

PHP Syntax

🎯 한 줄 통찰 (One-line insight)

PHP's case-sensitivity is asymmetric — keywords/functions/classes are case-INsensitive (ECHO works same as echo), but variable names are strictly case-SENSITIVE ($color and $COLOR are two completely different variables), a distinction the source demonstrates directly by showing the second echo silently printing nothing meaningful. [S1]

🧠 핵심 개념 (Core concepts)

• PHP tags — a script starts with <?php and ends with ?>. [S1]
• .php extension — default file extension; files mix HTML and PHP code freely. [S1]
• Semicolons required — all PHP statements end with ;. [S1]
• Case-insensitive: keywords, function names, class names, user-defined functions. [S1]
• Case-sensitive: variable names. [S1]

📖 세부 내용 (Details)

• Basic script structure: <?php echo 'Hello World!'; ?> embedded inside HTML. [S1]
• Keyword case-insensitivity: ECHO 'Hello World!<br>'; echo 'Hello World!<br>'; — both legal and equivalent. [S1]
• Variable case-sensitivity: $color = "red"; echo "My car is $color<br>"; echo "My house is $COLOR"; — $COLOR is undefined/different from $color. [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

• 대소문자 구분의 비대칭성: 키워드/함수/클래스는 대소문자 구분 없음, 하지만 변수명은 대소문자 구분됨이 명시적으로 대비됨. [S1]

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — HTML과 PHP 코드를 한 파일에서 혼합하는 것이 PHP 스크립트의 기본 작성 방식이다. [S1]

💻 코드 패턴 (Code patterns)

Variable name case-sensitivity trap (PHP):

<?php
$color = "red";
echo "My car is $color<br>";   // red
echo "My house is $COLOR";     // undefined — $COLOR != $color
?>

✅ 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 Install, PHP Comments, PHP Variables
• 참조 맥락: PHP 기본 문법 — 주석(Comments), 변수(Variables) 챕터로 이어짐.

📚 출처 (Sources)

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

📝 변경 이력 (Change history)

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