(PHP 7, PHP 8)
IntlChar::isJavaIDStart — Check if code point is permissible as the first character in a Java identifier
$codepoint): ?boolDetermines if the specified character is permissible as the start of a Java identifier.
In addition to IntlChar::isIDStart(), true for characters with general categories "Sc" (currency symbols) and "Pc" (connecting punctuation).
codepointThe int codepoint value (e.g. 0x2603 for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. "\u{2603}")
Returns true if
codepoint may start a Java identifier, false if not. Returns null on failure.
示例 #1 Testing different code points
<?php
var_dump(IntlChar::isJavaIDStart("A"));
var_dump(IntlChar::isJavaIDStart("$"));
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)