Add attribute with no value?

[adjenks]

I ran into an issue here:
<option t:for="language in languages" value="{{language['code']}}" t:attr="language['code'] == userLang ? selected='' ">{{language['name']}}</option>

How does one conditionally add a 'selected' attribute with no attribute value? Since that's how it's usually defined, by just existing, and not having any particular value.

If I use this:
t:attr="language['code'] == userLang ? selected
(no equals sign or value)
it crashes

and if I give it a null value selected=Null, it ends up giving it a zero length string in the tag like this:
selected=''

This is nit picky but I want to know if it's possible with just using Twital.

[goetas]

This depends if you are in XML or HTML5 mode.
See http://twital.readthedocs.io/en/latest/api.html#basics

$twital = new TwitalLoader($loader);
$twital->addSourceAdapter('/\.wsdl$/', new XMLAdapter()); // handle .wsdl files as XML
$twital->addSourceAdapter('/\.htm$/', new HTML5Adapter()); // handle .htm files as HTML5

[adjenks]

I configured the source adapter to use HTML5 as you suggested. However I still receive this error if I do not add a value to the "selected" attribute:

Type: Goetas\Twital\Exception
Message: Goetas\Twital\Attribute\AttrAttribute::findAttrParts error in 'selected'
File: /var/www/commlog_dev/vendor/goetas/twital/src/Goetas/Twital/Attribute/AttrAttribute.php
Line: 108

[adjenks]

This crashes: t:attr="language['code'] == userLang ? selected">
But this doesn't: t:attr="language['code'] == userLang ? selected='' ">
But I don't want the empty string.
Thank you for your time.