Apps are designed to enable usage without requiring detailed understanding of programming and so they can be applied in batch to a large amount of data. In other words, being able to use them as functions without writing loops or conditionals.

Apps can be used by themselves, or added together to define a “composed function” (aka pipeline). Composed functions can be applied to a single, or thousands, of data file(s).

Apps have several key features

  1. trap errors

  2. check the validity of input data

  3. can be used by themselves or combined into a “composed” app

  4. automatically track the relationship between an input data record and its output record