2 ms·

IO is a side effect, at least from the functional programming perspective.

• pjerem 3y ago
  Yes but also in FP perspective, a program without IO will not be ran at all. Except if you count static parameter to not be an input, then you have a static output which is basically a constant. Compiler may in fact try to transform it into a constant and if you don’t do anything with it, well, it’ll probably be marked as unused and not even embedded in your binary.
  • blowski 3y ago
    If you have a program that sends an email with fixed content to a fixed email address, whenever you run that program that email address will receive an email. Is the email an output, or a side-effect?
    • kaoD 3y ago
      It is an output or, in FP terms, a side effect. But you're discussing semantics here while it's obvious side effects mean different things in different contexts so the conversation won't get very productive.
    • deleted 3y ago
      [deleted]
    • ninkendo 3y ago
      Sending an email absolutely involves IO.