how to generate or change code in compile time?

Question

I want to add some code to start of function. like

source code:

func A(){
    do something...
}

final code:

func A(){
    ADDED CODE
    do something...
}

I`m using //go:generate right now,but it will change the source code and should run it every function changed,so I wonder if there any way to do the job in compile time

Does this answer your question? [How to set package variable using -ldflags -X in Golang build](https://stackoverflow.com/questions/47509272/how-to-set-package-variable-using-ldflags-x-in-golang-build) — The Fool, Feb 24 '22 at 08:21
The code I want to add is a little complex, so the -X is not applicable to me — 贺玉琨, Feb 24 '22 at 08:35

score 0 · Answer 1 · answered Mar 02 '22 at 10:05

What about using a function call to add code?

package mypkg

var extra = func() {}

func A() {
  extra()
  // ...do something
}

Then you can include or exclude an extra file to the same package:

package mypkg

func init() {
  extra = func() {
    // ADDED CODE
  }
}

You even could select from one ore more files with alternatives for the extra() function.

score -2 · Answer 2 · answered Feb 24 '22 at 08:10

-2

[H]ow to generate or change code in compile time?

You have to modify the compiler. (Don't do that.)

answered Feb 24 '22 at 08:10

Volker

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Not entirely true. You have the ldflag -X with which you can set strings. – The Fool Feb 24 '22 at 08:19

how to generate or change code in compile time?

2 Answers2