(PHP 7, PHP 8)
IntlChar::isIDStart — Check if code point is permissible as the first character in an identifier
Determines if the specified character is permissible as the first character in an identifier according to Unicode (The Unicode Standard, Version 3.0, chapter 5.16 Identifiers).
true
for characters with general categories "L" (letters) and "Nl" (letter numbers).
示例 #1 Testing different code points
<?php
var_dump(IntlChar::isIDStart("A"));
var_dump(IntlChar::isIDStart("$"));
var_dump(IntlChar::isIDStart("\n"));
var_dump(IntlChar::isIDStart("\u{2603}"));
?>
以上示例会输出:
bool(true) bool(false) bool(false) bool(false)
IntlChar::PROPERTY_ID_START