Nope, there’s not. A plugin feature has been discussed earlier, and here is a discussion about things like registering external functions (which might match what you’re looking for with hooks).
To summarise what I remember from seeing the discussions:
- Opening up Hugo to plugins and other custom code increases the workload and maintenance work of the Hugo team.
- Might give a more negative experience to users (slower Hugo, people needing to install extensions before a particular theme can be used).
- Organisational issues (things like, how to ensure people use the right function if a theme relies on them).
- Plugins have the potential to reduce the security of Hugo.
- And looking at the discussion about the possible
execshortcode: difficult to understand for non-developers (so documentation challenges).
(I’m not saying I’m against plugins or hooks, but just to recall here the points that I remember from previous discussions and issues on GitHub.)