I have some more free time nowadays after finishing my degree (yay).
The ETL doesn’t look very nice to me. I think the implementation is very partial and looks to me more like a bunch of shared utilities, which don’t live up to the name “Extended Template Library”.
At least the majority of the functionality is already implemented in the boost libraries, which have a very high quality, are broadly used, peer-reviewed and well tested.
We are already dependent on the boost libraries so why not use them to a bigger extent and get rid of the ETL as much as possible and simplify the code of synfig.
I will start replacing the ETL with boost libraries first in the command-line interface, then in synfig library and synfig modules and then in synfig-studio in this order.
Along the way I can most probably simplify/improve some stuff and make synfig’s code cleaner.
Follow the progress of the implementation in this branch of my repository: https://github.com/eldruin/synfig/tree/eldruin_etl_replacement
I also opened an issue in the bug tracker: http://www.synfig.org/issues/thebuggenie/synfig/issues/723