And then there are sealed DSLs... Byte encoder/decoder in Elm are opaque, so their implementation is hidden. A smart compiler, such as the one I am writing, ca

And then there are sealed DSLs... Byte encoder/decoder in Elm are opaque, so their implementation is hidden. A smart compiler, such as the one I am writing, can take advantage of that with compiler intrinsics that replace the implementation with something that the compiler itself optimizes.