I've also been explaining them the same way as Mark. On 10 September 2014 17:28, Plínio Balduino <pbaldu...@gmail.com> wrote:
> That's also my explanation about the use of exclamation mark. > > IMHO, +1 for volatile, without !. > > Plínio > > On Wed, Sep 10, 2014 at 1:05 PM, Mark Engelberg <mark.engelb...@gmail.com> > wrote: > >> When I explain to new Clojurists what the ! means, I explain that it >> calls attention to a mutation function that is unsafe to call inside a >> transaction. Many programmers coming from Scheme are used to thinking of ! >> as meaning *anything* involving mutation, but that's not the case in the >> Clojure. This more subtle distinction (that it needs to be unsafe in a >> transaction) clarifies why swap! has an exclamation point, but ref-set does >> not, even though both involve mutation. >> >> Assuming my description of Clojure's use of ! is correct (and if I'm >> wrong and am not thinking of some important counterexample, please let me >> know), then it doesn't really make sense for volatile to be called >> volatile!. Yes, volatiles are less safe than atoms, but the creation of >> the volatile itself is perfectly fine to occur in a transation. Only >> vswap! and vreset! require the exclamation point. >> >> I'd go one step further and question why we need new names vswap! and >> vreset!, when swap! and reset! are perfectly clear and sufficient. As >> Clojure has become increasingly interface and protocol-driven, it makes >> less and less sense to have a proliferation of function names for the same >> behavior on different underlying objects. vswap!, for example, is exactly >> the semantics you'd expect if you overloaded swap!, describing it as a >> function that can be applied to both atoms and volatiles, where volatiles >> are the more thread-unsafe, less atomic, alternative, because that's the >> nature of the underlying box. >> >> --Mark >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clojure@googlegroups.com >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+unsubscr...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
