Agree it can be done - not sure I would want to maintain that in a large system as you are paying the LOC penalty at every call site. Seems easier to just add the context callback in the methods themselves so then you are in control of the code penalty.
> On Sep 12, 2018, at 8:17 AM, Sebastien Binet <bi...@cern.ch> wrote: > > > > On Wed, Sep 12, 2018 at 2:55 PM robert engels <reng...@ix.netcom.com > <mailto:reng...@ix.netcom.com>> wrote: > Ok, now the coffee has kicked in, and it still has problems, because you > cannot call a method and use a return value other than error without multiple > signatures, unless you move all of the return values outside of the closure - > like his example does with var a. > > This would be extremely tedious (and probably error prone) to use IMO, > especially with Go’s multiple return values. > > one has to be careful, yes. but it's not completely out of reach. > > func Foo(a, b int) (int, error) { ... } > > func Do() { > var out = 0 > With(ctx, func() error { > var err error > out, err = Foo(42, 66) > return err > }) > } > > closures are great! (like fezzes and bowties, actually :P) > > -s > > >> On Sep 12, 2018, at 7:50 AM, robert engels <reng...@ix.netcom.com >> <mailto:reng...@ix.netcom.com>> wrote: >> >> Too early, and the coffee had not kicked in... >> >>> On Sep 12, 2018, at 7:49 AM, robert engels <reng...@ix.netcom.com >>> <mailto:reng...@ix.netcom.com>> wrote: >>> >>> Yes, you are correct. My bad :) >>> >>>> On Sep 12, 2018, at 7:34 AM, Sebastien Binet <bi...@cern.ch >>>> <mailto:bi...@cern.ch>> wrote: >>>> >>>> >>>> >>>> On Wed, Sep 12, 2018 at 2:23 PM robert engels <reng...@ix.netcom.com >>>> <mailto:reng...@ix.netcom.com>> wrote: >>>> I am pretty sure that is not correct, I am referring to: >>>> >>>>> func WithContext(context Context, f func() error) error { >>>>> context.__entry__() >>>>> defer context.__exit__() >>>>> return f() >>>>> } >>>> >>>> You will need a lot of WithContext methods - based on the different >>>> signatures of function f. >>>> >>>> See the main method… I am assuming this is attempting to be a general >>>> facility - and thus the signature of f will vary. >>>> >>>> you just need to wrap it with a closure, just as Eric did: >>>> >>>> e.g.: >>>> func QueryDB(a,b int) error { ... } >>>> >>>> WithContext(ctx, func() error { >>>> return QueryDB(42, 666) >>>> }) >>>> >>>> and voila. >>>> >>>> -s >>> >>> >>> -- >>> 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 >>> <mailto:golang-nuts+unsubscr...@googlegroups.com>. >>> For more options, visit https://groups.google.com/d/optout >>> <https://groups.google.com/d/optout>. >> > > > -- > 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 > <mailto:golang-nuts+unsubscr...@googlegroups.com>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. -- 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. For more options, visit https://groups.google.com/d/optout.
