Uses of reflect and unsafe packages

[Ketan Rathod]

I have seen many discussions using refflect and unsafe packages, so i am curious to know their usecases and when it is useful to use this packages.

[Jason E. Aten]

I use "unsafe" for performance optimization and with Cgo[1][2][3]. 

I use "reflect" and "unsafe" for doing de-serialization in a serialization framework, 

and for cross-language work (Go <-> C, Go <-> scripting languages like Python, R, Lua, zygomys)[4][5][6]. 

If you are staying entirely within the Go language, then you aren't likely to need "reflect". It lets

you write very dynamic code to handle a Go struct whose layout you don't know about at compile

time.  You give up type safety. It is usually alot of painstaking work.

If you aren't profiling your code for performance tuning, you likely won't need to mess with "unsafe".

It does let you avoid certain redundant allocations if you can guarantee things about your memory's

access patterns.

Since, as the ancient maps used to say, "here be dragons," it is better to leave both of them alone until you really, really need them.

examples:

[1] https://github.com/glycerine/embedr/blob/96d03afc338c43add0f473ef1ea36ed7257b69f1/r2go.go#L762

[2] https://github.com/glycerine/embedr/blob/96d03afc338c43add0f473ef1ea36ed7257b69f1/embedr.go#L255

[3] https://github.com/glycerine/greenpack/blob/971e607bf20009e551605ed6a8480335629241f8/msgp/unsafe.go#L34

[4] https://github.com/glycerine/greenpack/blob/971e607bf20009e551605ed6a8480335629241f8/msgp/write.go#L775

[5] https://github.com/glycerine/zygomys/blob/b4e08088004ee5de19f294d53bb692122463aa10/zygo/callgo.go#L15

[6] https://github.com/glycerine/rmq/blob/master/src/rmq/rmq.go#L466