On Mon, Jul 6, 2020 at 6:46 PM <kurnia.d....@gmail.com> wrote: > > to my understanding, a pure function is a function that doesn't have a > side effect, so we can limit pure function to: > - unable to call non-pure function > - unable to modify a variable that is not declared on current function > (like a global variable) > > You also need an additional property, namely that the function always returns the same output for a given input. That is, it is a "stable" relation from inputs to outputs. Consider e.g.
https://play.golang.org/p/XI4IgfiLoub where we read a global variable as part of the function body. You could make this into an escaping variable in a closure if you want something more local, but the global will serve the same purpose. There are many variants of this scheme, for instance by reading on a channel as part of the function body, and having that channel fed random values, etc. Marking an expression as pure is a nominal type of language construction. Go usually prefers structural language constructions in most places, so I don't think it fits into the language design as a whole. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAGrdgiUj339ySGiG5L2aE7jrV4OfhDr%2BW73%2B%2B4w49VG%2BrLFUNw%40mail.gmail.com.
