DRY variable setting across templates (macro for variable?)

Question

I have a need for something like the following:

{# Template A #}
    {# Do X that sets variable x #}
    {# Do Y that sets variable y #}
    {# Pass x and y into A include partials #}

{# Template B #}
    {# Do X that sets variable x #}
    {# Do Y that sets variable y #}
    {# Pass x and y into B include partials #}

The logic for X and Y is the same in templates A and B.

Is there a way to write each once in some kind of dedicated partial and place them in templates A and B, something akin to return in a JavaScript function?

I'm not sure there is. I think that macros only produce front-end output. And so I have to duplicate the logic in each template. Is that right?

Answer 1

As you noted in your comment, the Twig Perversion plugin will do exactly what you need. It allows you to return a value from a macro, which isn't typically something that Twig permits.

Personally, I'd consider it to be fairly safe to rely on this plugin for a few reasons. Marion is a long-standing and trusted developer in the community, the plugin is relatively simple, and could easily be replaced with a small custom module if it ever went defunct. It also doesn't touch your data, so removing it in the future won't cause any problems.