IntlChar::isJavaIDStart

(PHP 7, PHP 8)

IntlChar::isJavaIDStart — Check if code point is permissible as the first character in a Java identifier

说明

public static IntlChar::isJavaIDStart(int|string $codepoint): ?bool

Determines if the specified character is permissible as the start of a Java identifier.

In addition to IntlChar::isIDStart(), true for characters with general categories "Sc" (currency symbols) and "Pc" (connecting punctuation).

参数

codepoint: The int codepoint value (e.g. 0x2603 for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. "\u{2603}")

返回值

Returns true if codepoint may start a Java identifier, false if not. Returns null on failure.

示例

示例 #1 Testing different code points

<?php
var_dump(IntlChar::isJavaIDStart("A"));
var_dump(IntlChar::isJavaIDStart("$"));
var_dump(IntlChar::isJavaIDStart("\n"));
var_dump(IntlChar::isJavaIDStart("\u{2603}"));
?>

以上示例会输出：

bool(true)
bool(true)
bool(false)
bool(false)

参见

IntlChar::isIDStart() - Check if code point is permissible as the first character in an identifier
IntlChar::isJavaIDPart() - Check if code point is permissible in a Java identifier
IntlChar::isalpha() - Check if code point is a letter character

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