> a derivation is the reification (or realisation, as in, "make it real") of a function call on the filesystem. IOW the concrete result is derived from the func

> a derivation is the reification (or realisation, as in, "make it real") of a function call on the filesystem. IOW the concrete result is derived from the function call, memoized using content addressing. The docs are much better at describing this as "a derivation is a build task." I don't care that it's the return value of a function call, I don't care that because the language is purely functional it may be called lazy and memoized and so on. They are interesting technologically, but the abstraction is bad if it is so leaky you need to understand the internals to use it. > You could say that derivations are like packages, but that would be a lie, > a flake is a central definition of a number of target derivations in the context of a specific source state of dependencies. It's a package. More specifically, a package definition or description. People understand that the result of package installation depends on the total resolution of dependencies and this may be fairly fine grained or a difficult to parse graph (they just trust that the package manager does the "right" thing). Most modern package managers do this and it's not confusing to call it a package (although, it's in good company because every package manager likes to call their packages something cute and different).