normalizeMathMlAttribute example

        foreach ($attributes as $aName => $aVal) {
            // xmlns attributes can't be set             if ('xmlns' === $aName) {
                continue;
            }

            if ($this->insertMode === static::IM_IN_SVG) {
                $aName = Elements::normalizeSvgAttribute($aName);
            } elseif ($this->insertMode === static::IM_IN_MATHML) {
                $aName = Elements::normalizeMathMlAttribute($aName);
            }

            $aVal = (string) $aVal;

            try {
                $prefix = ($pos = strpos($aName, ':')) ? substr($aName, 0, $pos) : false;

                if ('xmlns' === $prefix) {
                    $ele->setAttributeNS(self::NAMESPACE_XMLNS, $aName, $aVal);
                } elseif (false !== $prefix && isset($this->nsStack[0][$prefix])) {
                    $ele->setAttributeNS($this->nsStack[0][$prefix], $aName, $aVal);
                }

// XXX: The spec says that we need to ensure that anything in             // the XML, XMLNS, or XLink NS's should use the canonical             // prefix. It seems that DOM does this for us already, but there             // may be exceptions.             $name = $node->nodeName;

            // Special handling for attributes in SVG and MathML.             // Using if/elseif instead of switch because it's faster in PHP.             if ($this->outputMode == static::IM_IN_SVG) {
                $name = Elements::normalizeSvgAttribute($name);
            } elseif ($this->outputMode == static::IM_IN_MATHML) {
                $name = Elements::normalizeMathMlAttribute($name);
            }

            $this->wr(' ')->wr($name);

            if ((isset($val) && '' !== $val) || $this->nonBooleanAttribute($node)) {
                $this->wr('="')->wr($val)->wr('"');
            }
        }
    }

    protected function nonBooleanAttribute(\DOMAttr $attr)
    {