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    IntlChar::isIDStart

    (PHP 7, PHP 8)

    IntlChar::isIDStart — Check if code point is permissible as the first character in an identifier

    Description

    public static IntlChar::isIDStart(int|string $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).

    Parameters

    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}")

    Return Values

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

    Examples

    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}"));
    ?>

    The above example will output:

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

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