It was very interesting to see @josevalim going more or less down the same paths while solving a problem similar to my own with my Vampyre/PhoenixUndeadView project.
It’s amazing the way he managed to live code all of that without any preparation. My own solution to more or less the same problem is clearly over-engineered when compared to @josevalim’s solution, but it solves a different problem with different requirements, so it can’t be directly compared. My implementation also took much longer and is not as elegant (again, different requirements, so they can’t be directly compared).
I guess the main take-away from @josevalim’s video is that one can be very naïve when naming the variables, because variables nested deeper into the template will not overwrite the ones outside. I believe I had proved that to myself, but I still wanted unique names, so I went ahead anyway… I still think there is some value in having unique variable names (it makes it easier to inspect the compiled output), but seeing how much simpler it is to implement it the way @josevalim did it, I guess I think it’s not worth it to do it like I did.
The main difference between the new EEx improvements and Vampyre (and the reason why you can’t compare both probjects) is that EEx doesn’t attempt to expand macros and optimize the result (it wouldn’t even make sense in the case of such a generic project as EEx). It might make sense in a more specialized engine, like Vampyre, or the engine in Phoenix.HTML, where one expects a library of widgets to be available. That way, optimizing those widgets as much as possible makes sense.
I’m still betting on using macros to do as much work as possible at compile-time and generate templates which are as optimized as possible, and regenerate all the dynamic parts each time the template is rendered. That is not as bad as it sounds, as I’ve managed to make the dynamic parts as minimal as possible and to make my templates as flat as possible.
On the other hand, @josevalim is now thinking about optimizing the templates by building a dependency graph on the template assigns, so that it’s possible to optimize only those segment that depend on the data that has changed.
Anyway, this was an amazing video