there is a way i can do the base, but we still change old function due limit on go
https://gist.github.com/Petelin/a7bf8ccfd657536d46aaa355c6dc421a 在 2019年11月2日星期六 UTC+8下午4:50:22，林风写道： > > you may say i can write a fib2 which have fib1+counter. but that is really > bad way to write code. and that's why we need decorator. > > 在 2019年11月2日星期六 UTC+8下午2:30:33，burak serdar写道： >> >> On Sat, Nov 2, 2019 at 12:20 AM 林风 <petel...@gmail.com> wrote: >> > >> > let's say i have a function or method to get fib >> > >> > func fib(n int){ >> > ... >> > return fib(n-1) + fib(n-2) >> > } >> > >> > >> > now i want to add a counter to track how many times i have called to >> fib. >> > >> > in python or jave i can easy use `decorator patten` to do it. >> > >> > but in go, you can not change fib since it is a function. if you define >> fib as a method, you cannot do it either since go did not have `Inherited`. >> you cannot call father class. >> > >> > so golang did not support such thing? can we just reflect to do so? >> >> >> There is no built-in way to do that. I don't think you can do that >> with reflect either. However, if you need such decorators, you can use >> an interface or a function pointer: >> >> type fib interface { >> fib(int) int >> } >> >> func f(in fib) { >> in.fib(...) >> } >> >> You can pass in an implementation of fib that will do whatever you want. >> >> With a function pointer: >> >> func f(fib func(int) int) { >> fib(...) >> } >> >> And if you need to count how many times f calls fib: >> >> ... >> count:=0 >> f(func(in int) int { >> count++ >> return originalFib(in) >> } >> } >> >> >> >> > >> > >> > >> > >> > >> > >> > -- >> > 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 golan...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/84685fb5-8657-4f57-94f1-4b444d722976%40googlegroups.com. >> >> >> > -- 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/ad4658a5-c6a6-4cfb-ad48-95ce8ecbfa2b%40googlegroups.com.
