People have tried, and failed, countless times to create thick abstractions over runtimes in order to allow code to easily port across them. They always fail, n

People have tried, and failed, countless times to create thick abstractions over runtimes in order to allow code to easily port across them. They always fail, normally because they become too slow due to the added indirection and lost opportunities to optimize using platform-specific features. Moreover, it's not even that useful; how often do you want to move a large application from the JVM to the CLR? The code sharing capabilities between Clojure and ClojureScript exemplifies a better middle ground; you write .cljc files and use reader conditionals to write platform-specific code when necessary.