(PHP 7)
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).
Returns TRUE if
codepoint may start an identifier, FALSE if not.
Example #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}"));
?>
以上例程会输出：
bool(true) bool(false) bool(false) bool(false)
IntlChar::PROPERTY_ID_START