Yeah this is a good observation. Some related papers I saved: Miniphases: compilation using modular and efficient tree transformations, Odersky et al. https:

Yeah this is a good observation. Some related papers I saved: Miniphases: compilation using modular and efficient tree transformations, Odersky et al. https://scholar.google.com/scholar?cluster=7946863864036706551&hl=en&as_sdt=2005&sciodt=0,5 https://scholar.google.com/scholar?cluster=79468638640367065... (I'd be interested if anyone has any knowledge of how this actually worked out in the Scala compiler; I don't have experience with it) TreeFuser: a framework for analyzing and fusing general recursive tree traversals. This one said they prototyped it in Clang. https://dl.acm.org/doi/abs/10.1145/3133900 https://dl.acm.org/doi/abs/10.1145/3133900 Deforestation: Transforming programs to eliminate trees, Wadler https://scholar.google.com/scholar?cluster=13826873296507613488&hl=en&as_sdt=0,5&sciodt=0,5 https://scholar.google.com/scholar?cluster=13826873296507613... I think the key point is that some of the frameworks introduce restrictions that make it hard to write a big program like a compiler. There is a hard tradeoff between the amount of fusing that can be done and how expressive the metalanguage is. --- related: https://github.com/oilshell/oil/wiki/Compact-AST-Representation https://github.com/oilshell/oil/wiki/Compact-AST-Representat... (compiling programs that operate on trees to operate on packed representations)