How to call function from struct in slice?

[Jay]

In a code example, I’m confuse if it’s possible to call ModuleName() each package API after execute CompileModules()?

app.go

func CompileModules() []interface{

    return []interface{

        Example1.AddModule(),

        Example2.AddModule(),

        Example3.AddModule(),

    }

}

Init.go in Hello1 folder:

package Example1

type AddModule struct {}

func (p *AddModule) ModuleName() string {

    return “Hello 1”

}

[Henry]

You need to cast the generic interface{} to its appropriate type. For instance:

```

modules := CompileModules()

for _, module := range modules {

      mod, ok := module.(*AddModule)

      if !ok {

            //error handling if module is not of type AddModule

      }

      fmt.Println(mod.ModuleName())

}

```

[James Lei]

To add on, the return value of mod is "<nil>"

fmt.Println(mod)

[James Lei]

I tried your solution and it still can't find .ModuleName(), 

modules := vendorpackages.CompileModules()

    for _, module := range modules {

        mod, ok := module.(*AddModule)

    if !ok {

        //error handling if module is not of type AddModule

    }

    fmt.Println(mod.ModuleName()) // No such method

}

Does it mean I'll need to declare method in AddModule struct?

type AddModule struct {

    ModuleName()

}

On Saturday, 4 June 2022 at 11:40:15 UTC+8 Henry wrote:

[James Lei]

I have nearly solve the problem, except I have to use cast as mod.(*Example1.AddModule) which is wrong.

How do you cast as mod.(*AddModule)?

On Saturday, 4 June 2022 at 11:40:15 UTC+8 Henry wrote:

[jake...@gmail.com]

I find your example code confusing, and it appears to have multiple syntax errors, which make it impossible to compile. If you could post a complete "working" example to the playground you would probably get a better response.

[Little Ant]

Thank you Jake, 

I have not have a complete working solution, but I have included comments to understand the feature I'm trying to build to add or remove my custom modules similar to written CMS that add and remove modules/plugins. Unsure if I should go by "receiver" way or method way.

https://go.dev/play/p/38sL3P-BSDr

[Henry]

I have no idea what problem you are facing. Your example is not clear enough to me. I think you may have several other problems in the mix as well (such as calling code from another package, etc.). Try reading the compiler error and see if it helps. 

I have included a more elaborate example. Hopefully, it helps point you toward the right direction. https://go.dev/play/p/HMnjBnl7eL5  

[jake...@gmail.com]

Your playground example was still not runnable.

I have fixed it so it runs: https://go.dev/play/p/I57OftEerLY

Now that we have a working example, what precisely is the problem you are having?