Maybe he has this in mind: Imagine a high-level, straightforward imperative language X whose only purpose is to specify libraries and data structures. This X h

Maybe he has this in mind: Imagine a high-level, straightforward imperative language X whose only purpose is to specify libraries and data structures. This X has strong typing, memory safety and maybe also memory alignment directives but abstracts away as much as possible from any actual environment/platform/CPU layout. It has a precise semantics and even some ways of specifying pragmatics (e.g. big O runtime behavior of functions). In X you write "pure" algorithms that do not access (m)any OS-dependent features. Libraries in this language are then transpiled to various target languages and platforms. To use all libraries that have ever been written for X, someone only needs to write a transpiler-backend for the target language/platform once. LLVM intermediate language is similar but too low-level. Think about a high-level counterpart.