Functions, in the sense that there are global variables, is strongly discouraged by the language. It's usually much easier to define a type so there is a clear

Functions, in the sense that there are global variables, is strongly discouraged by the language. It's usually much easier to define a type so there is a clear delineation. That is, from Mongo, you use Serde and wind up with only valid records operated upon, of a table of such values.