(PHP 7, PHP 8)
IntlChar::isIDStart — Check if code point is permissible as the first character in an identifier
$codepoint
): ?bool
Determines if the specified character is permissible as the first character in an identifier according to Unicode (The Unicode Standard, Version 3.0, chapter 5.16 Identifiers).
true
for characters with general categories "L" (letters) and "Nl" (letter numbers).
codepoint
The int codepoint value (e.g. 0x2603
for U+2603 SNOWMAN), or the character encoded as a UTF-8 string (e.g. "\u{2603}"
)
Returns true
if
codepoint
may start an identifier, false
if not. Returns null
on failure.
示例 #1 Testing different code points
<?php
var_dump(IntlChar::isIDStart("A"));
var_dump(IntlChar::isIDStart("$"));
var_dump(IntlChar::isIDStart("\n"));
var_dump(IntlChar::isIDStart("\u{2603}"));
?>
以上例程会输出:
bool(true) bool(false) bool(false) bool(false)
IntlChar::PROPERTY_ID_START