3 ms·

>If you want to get shit done, and make sure the types are correct, and make sure all side effects are properly managed and accounted for, that's Haskell's nich

• tsm 10y ago
  Clojure's immutable types mean just that—the values are immutable (e.g., in CL you could do (defvar x 42) (setf x 84), but in Clojure the equivalent is not allowed). But there are many more side effects than changing variables. Clojure makes no guarantees that a given function is referentially transparent, nor does it promise that a given function doesn't write to stdout/stderr, read from stdin, change the file system, make a network connection, send missiles to foreign countries, etcetera.
  • sarnowski 10y ago
    Not arguing that the following method can be trusted as much as in Haskell but properly used also prevents this kind of scenario: https://clojuredocs.org/clojure.core/io℅21 https://clojuredocs.org/clojure.core/io℅21 The 'io!' macro marks a code block to have side effects which prevents using it in a STM transaction as 'dosync' might need to execute the functions multiple times in case of conflicts during the optimistic locking.
    • catnaroek 10y ago
      > properly used In the sense C programmers use the term? Why should humans be trusted with identifying all operations that can't be safely performed within a transaction?