src/Parser/ResultMapper/StandardDateFragmented.php
protected function determineWeekIndex(DateLexerResult $parts)
    {
        if (null === $w = $parts->get('W')) {
            return null;
        }

        return intval($w) - 1;
    }
protected function determineWeekIndex(DateLexerResult $parts)
    {
        if (null === $w = $parts->get('W')) {
            return null;
        }

        return intval($w) - 1;
    }
protected function determineWeekIndex ( DateLexerResult $ parts ) { if ( null === $ w = $ parts -> get ( 'W' ) ) { return null ; } return intval ( $ w ) - 1 ; }
Determine ISO week index from iso week number.

@param DateLexerResult $parts

@return integer|null
Determine ISO week index from iso week number .