I don't think this is a valid question with the errors package as the only option is (if err == myerrors.ErrValue) because errorString is private to the package. Therefore you cannot do (if e, ok := err.(*errors.errorString); ok).
On Saturday, 10 December 2016 21:36:34 UTC, parais...@gmail.com wrote: > > The first question you need to ask yourself is are you going to use errors > as values ( if err == myerrors.ErrValue ) or errors as types ( if e,ok:= > err.(*myerrors.ErrType ; ok ) > > Le samedi 10 décembre 2016 20:10:26 UTC+1, Jon a écrit : >> >> I would like to know what my default practice should be when returning >> structs from functions. Should I return a value or a pointer? (Assume I >> don't need the functionality of returning a pointer and my struct contains >> at most one simple field so a vast copy isn't needed if I return a value.) >> >> A specific example could be the errors package >> <https://golang.org/src/errors/errors.go> with errors.New. >> >> The New function is implemented by returning an errorString pointer: >> <https://play.golang.org/p/WPmP8ZVS0_> >> >> func New(text string) error { >> return &errorString{text} >> } >> >> Could it just as easily have been implemented by returning an errorString >> value <https://play.golang.org/p/Gawy-mgw2X>? If so why was the pointer >> return chosen over value return? >> >> func New(text string) error { >> return errorString{text} >> } >> >> Could it also have been implemented as below >> <https://play.golang.org/p/H2NIARHO-Y> which looks even simpler? >> >> func New(text string) error { >> return errorString(text) >> } >> // errorString is a trivial implementation of error. >> type errorString string >> >> func (e errorString) Error() string { >> return string(e) >> } >> >> What was the thought process that went into the implementation of the >> errors package? Were the latter two implementation options I suggest >> considered? If so why were they disregarded? Performance? Coding standards? >> Heap allocation benefits? >> > -- 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.
