typedef should be defined in the current scope

[yulvil]

Typedefs are always transpile into global-scope go types. We should preserve the scope in which they were defined.

I have not seen real world example of that, and I would think it is a bad practice to reuse the same name for 2 different types. For those reasons I would label this issue as a "Low". We can fix it when we encounter the problem.

P.S. This could happen when importing a library.

double f1() {
    typedef double mynum;
    mynum d = 2.2;
    return d;
}

int f2() {
    typedef int mynum;
    mynum i = 123;
    return i;
}

int main() {
    double d = f1();
    int i = f2();
    return (int)(i + d);
}

Currently transpiles to:

package main

import "os"
import "github.com/elliotchance/c2go/noarch"

type mynum float64    // <-- global scope instead of local. "type mynum int" overwritten

func f1() float64 {
...

Ref: #272

[elliotchance]

I guess a longer term solution would be to incorporate the function name into the type. However, I agree that its a pretty silly thing to do and I have never seen it done in code either. I didn't even know you could do that until you raised the issue...

[Konstantin8105]

Could you solve that point at globally?

Preliminary steps:

1. Move(combine) body from function func newDeclStmt(a *ast.VarDecl, p *program.Program) to function func transpileVarDecl(p *program.Program, n *ast.VarDecl)
2. Remove function func newDeclStmt(a *ast.VarDecl, p *program.Program)
3. Change design of function from func transpileToNode(node ast.Node, p *program.Program) error to func transpileToNode(node ast.Node, p *program.Program) (decls []goast.Decls, err error). Added returns
4. Change design of all function inside func transpileToNode like in step 3.
5. Remove fully body of function func transpileDeclStmt(n *ast.DeclStmt, p *program.Program) and add...(See prototype at the end of that message).

At the end:

• we create change transpileToNode to recursive function(It is nice)
• all structures, enums, ... are allowable inside function.
• If we add some features (for example, another support for enum), then we can change on transpileToNode, but not in 2 places tranpileToNode and newDeclStmt.

Nice prototype of that changes see #345. Generally, prototype is work(only one FAIL in transpiling of file sqlite3.c, but I don't have time,now, for solving).
@yulvil , Could you clarify your point of view.

[Konstantin8105]

One more note for step 4 : change p.File.Decls to decls. (see prototype)

[elliotchance]

@Konstantin8105 I think that is too much since typedefs cannot be nested in anything - only some node types. Also there is the p which managed global state like types and structures so theres no need to change this much code.

[Konstantin8105]

@elliotchance Yes are right, if we think only about a typedef struct. The real reason for that big changes to support enum..., typedef enum name..., typedef enum...(without name), struct name, typedef struct name... everywhere - and outside of function and inside of function.