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

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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-callback-functions	PHP Callback Functions	Programming_Language	draft	conceptual		anonymous function callback PHP 콜백 함수		B	0.9	2026-07-04	2026-07-04			php programming w3schools callback functions	https://www.w3schools.com/php/php_callback_functions.asp

PHP Callback Functions

🎯 한 줄 통찰 (One-line insight)

A named function used as a callback is passed as a plain STRING ("myfunction"), not as a special function-reference syntax — meaning any existing function automatically qualifies as a callback with zero extra syntax, while anonymous functions are defined inline specifically for one-off, unnamed use cases. [S1]

🧠 핵심 개념 (Core concepts)

• Callback function — a function passed as an argument into another function. [S1]
• Named function callback — pass the function's name as a string: array_map("myfunction", $numbers). [S1]
• Anonymous function callback — defined inline: array_map(function($n) {return($n * $n);}, $numbers). [S1]
• Callbacks in user-defined functions — a parameter holding a function is invoked by adding parentheses: $format($str). [S1]

📖 세부 내용 (Details)

• Named function as callback: function myfunction($n) { return($n * $n); } $numbers = [1, 2, 3, 4, 5]; print_r(array_map("myfunction", $numbers));. [S1]
• Anonymous function as callback: $res = array_map(function($n) {return($n * $n);}, $numbers);. [S1]
• Callback passed to a user-defined function: function printFormatted($str, $format) { echo $format($str); } printFormatted("Hello world", "exclaim"); printFormatted("Hello world", "ask"); (where exclaim and ask are separately-defined named functions). [S1]

⚖️ 모순 및 업데이트 (Contradictions & updates)

소스에서 모순되는 정보는 발견되지 않음.

🛠️ 적용 사례 (Applied in summary)

현재 발견된 실제 적용 사례가 없습니다 — array_map()에 콜백을 전달해 배열의 모든 요소를 변환하는 것이 함수형 스타일 배열 처리의 대표 사례다. [S1]

💻 코드 패턴 (Code patterns)

User-defined function accepting a callback (PHP):

function exclaim($str) { return $str . "! "; }
function printFormatted($str, $format) {
    echo $format($str);
}
printFormatted("Hello world", "exclaim");

✅ 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 Filter Advanced, PHP JSON, PHP Arrays Functions
• 참조 맥락: 함수를 인자로 전달하는 패턴 — JSON 챕터로 이어짐.

📚 출처 (Sources)

• [S1] W3Schools — PHP Callback Functions — https://www.w3schools.com/php/php_callback_functions.asp

📝 변경 이력 (Change history)

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