4 ms·

You've definitely used Functors or Semigroups as well, you just didn't realize it.

• tsimionescu 6y ago
  Here is my problem with these ideas in programming: if you recognize that some common construct is in fact a semigroup or functor, does knowing this actually buy you anything? I suppose it might help sometimes when designing an abstraction, to guide you to some nice properties, such as easy composition.
  • codygman 6y ago
    > if you recognize that some common construct is in fact a semigroup or functor, does knowing this actually buy you anything? At least in Haskell one thing it means is you can use lots of new helper functions. > guide you to some nice properties, such as easy composition. Yep, which gets you code re-use for one.
  • rotifer 6y ago
    While playing around with a problem at work involving Markov chains and graph connectivity, I found it useful to know that I could write (in Java) a generic method that performed "exponentiation by squaring" on semigroups. So, in addition to being able to raise numbers to powers I could also use it on matrices whose elements belonged to a semiring. That is, I could use the same code on a matrix of doubles with "times" and "plus" (for the Markov chains), as well as a matrix of booleans with "and" and "or" (for the graph connectivity). (Of course, I could have used special purpose libraries, but these were small problems and it was fun. :)