Is the l10n "$string | loc" syntax supported by xgettext?

[Kevin Goess]

In a past job in Catalyst/TemplateToolkit we used the "string | loc" syntax for l10n. I like the syntax and was hoping to do something like this in a new Xslate project we're working on

    <: $string | loc :>

I'm not seeing any options in xgettext that support that for string extraction, and all the examples I see use the syntax

   <: loc($string) :>

Is there any support for the first syntax? Does anybody do it that way? Or should I just go with loc($string)?  I never looked at the implementation in that old job, so I don't know how we did it there.