(1) Homoiconic languages are actually a smaller scale instance of exactly what I'm talking about. They were designed from the ground up to allow for compile-tim

(1) Homoiconic languages are actually a smaller scale instance of exactly what I'm talking about. They were designed from the ground up to allow for compile-time code rewriting, and because that was the primary driving goal from the start, they have amazing code rewriting capabilities that other languages cannot begin to dream of. But the distinction I was trying to draw is that I'm talking about going further with that idea. Homoiconic syntax only allows for local code re-writing, but there are many other kinds of things we'd like to programmatically transform on a large codebase. Half-baked examples: We'd like to replace all use of new/delete with smart pointers, but only in source files that are in one particular section of the codebase. Or we'd like to move all our unit tests from being in a separate package/dll, to being included in the same dll but surrounded by compiler pragmas. (2) How the language would differ -- I don't yet know. But just as homoiconicity says "let's allow our end goal of automatic code rewriting to dictate our syntax", what I'm trying to say is, "let's allow our end goal of automatic refactorability / transformability to dictate all the programming language design decisions we make." I think probably many of the things Raphael_Amiard mentions in this thread would be a part of it: strong inferred typing, perhaps, and a strong package system. Perhaps the ability to write some kind that was intentionally agnostic about how it would be packaged, and write some code elsewhere that says "take that code over there, and package it thusly." It would need to know if certain snippets were functionally pure (sort of how D does with "pure nothrow"), because then it would know it have more freedom with how it could transform that code. Hopefully that clarifies the idea. It's hand wavy and high level, but it's a new (to me) idea that's only at the hand wavy stage so far.