Date::Calc::check_date is C, 
boolean DateCalc_check_date(Z_int year, Z_int month, Z_int day)
{
    if ((year >= 1) and
        (month >= 1) and (month <= 12) and
        (day >= 1) and
        (day <= DateCalc_Days_in_Month_[DateCalc_leap_year(year)][mont
+h]))
            return(true);
    return(false);
}

[download]
and it basicly uses: 
boolean DateCalc_leap_year(Z_int year)
{
    Z_int yy;

    return( ((year AND 0x03) == 0) and
            ( (((yy = (Z_int) (year / 100)) * 100) != year) or
                ((yy AND 0x03) == 0) ) );
}

const Z_int DateCalc_Days_in_Year_[2][14] =
{
    { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
    { 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};

const Z_int DateCalc_Days_in_Month_[2][13] =
{
    { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
    { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};

[download]
how to use (rewrite) it in perl

In reply to Re: ultimate date check regexp by Anonymous Monk
in thread ultimate date check regexp by Anonymous Monk

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