struct scope problem

[Konstantin8105]

Let's look on next C example:

struct tt {
        int t;
};

void some(void){
        struct tt{
                char* t;
        };
        struct tt u;
        u.t = "Uuups";
}

int main(void){
        struct tt u;
        u.t = 5;
        return 0;
}

We have 2 structs with same names tt and different internal items.
What we have after transpiling?

package main
import "github.com/elliotchance/c2go/noarch"
type tt struct {
        t int
}
func some() {
        var u tt    ///// <<<----   STRUCT IS GONE.
        u.t = noarch.ByteSliceToInt([]byte("Uuups\x00"))
}
func main() {
        __init()
        var u tt
        u.t = 5
        return
}
func __init() {
}

It is happen, because Struct is global variable of program:

c2go/program/program.go

Lines 55 to 58 in a7ac059

	// The definitions for defined structs.
	// TODO: This field should be protected through proper getters and setters.
	Structs StructRegistry
	Unions StructRegistry

How to solve that?
Create a scope for structs. Preliminary steps (in my point of view):

1. remove global variable Struct from Program
2. add Struct var , here:
   

   c2go/transpiler/transpiler.go

   Lines 31 to 33 in a7ac059

   	// Now begin building the Go AST.
   	err = transpileToNode(root, p)

3. If we going inside function we have to create a copy of Struct var:
   

   c2go/transpiler/transpiler.go

   Lines 358 to 363 in a7ac059

   	case *ast.FunctionDecl:
   	err := transpileFunctionDecl(n, p)
   	if err != nil {
   	return err
   	}

   
   add for this
   

   c2go/transpiler/transpiler.go

   Line 323 in a7ac059

   case *ast.TranslationUnitDecl:

P.S. : Like I understood, same problem with unions.
P.P.S: Implementation of that issue only after success of #344.

[elliotchance]

Another solution that would require less refactoring:

1. When you find a struct inside a function add the name of the function to the struct (so all structs are global still). For example there would be a struct tt and struct main_tt.
2. When resolving a type use the current function first, so always search for struct main_tt, then struct tt

Keeping all types in global space will also make things like removing duplicate code easier and making the output code more simple.

[Konstantin8105]

Also good example #346

[Konstantin8105]

@elliotchance , For myself is not clear about a reason for duplicates.
Could you clarify?
After #384 , we haven't any duplicate for multi file C code case.

[elliotchance]

In the first example there are two structs that have the same name. If we move both of them to global space then then names will clash or one will replace the definition of the other. We would have to rename the struct inside the main function to prevent this.

[Konstantin8105]

Also, example:

void rr()
{
   {
        struct tt{
                char* t;
        };
        struct tt u;
        u.t = "Uuups";
   }
   {
        struct tt{
                double t;
        };
        struct tt u;
        u.t = 42.24;
   }
}