Why do our programs need to read input and write output?
What&#x27;s the appeal of taking pure functional all the way to an executable tautology? Inputs can be passed around in a pure FP world without reducing purity, so why remove them?<p>We never got around to output at all. Assuming the compiler can&#x27;t write the output file before the program runs, how would you see the result of any program run in this world?<p>What about UI or network input?<p>I&#x27;m imagining that if only the compiler were allowed to do I&#x2F;O, I&#x27;d have to rebuild Chrome whenever I wanted to see a new site, or even see an update to a site, or change my preferences. Wait, scratch that, I can&#x27;t change preferences, because it can&#x27;t save. Is the shell allowed to do I&#x2F;O? What about output to the monitor, does that count? It&#x27;s not a file, but it&#x27;s Turing equivalent to an output file.