C - Union of struct and array, ugly syntax

I'm writing some floating pointer vector types in C. Using a union, I can get both struct and array representations of the same type, depending on which is more convenient. The syntax is very ugly, though:

#include <stdio.h>
#include <tgmath.h>
typedef union {
    struct { float x, y; };
    float val[2];
} vec2;
int main(int argc, char *argv[]) {
    vec2 herp = {{3, 4}}; // using {3, 4} throws an error when -Wall is enabled
    printf("Vector: {%f, %f}\n", herp.x, herp.y);
    float len = sqrt(herp.x * herp.x + herp.y * herp.y);
    printf("Length: %f\n", len);
    vec2 normalized = {{herp.val[0] / len, herp.val[1] / len}};
    printf("Normalized: {%f, %f}\n", normalized.val[0], normalized.val[1]);
}

Is there any way, using C99, C11, or possibly even GNU C extensions, that I can get syntax like the following?

vec2 derp = {6, 20}; // no need for two sets of braces in initializers
derp[0] = 5; // "anonymous" array

or am I better off making my vectors only structs or only arrays, and casting them to the other type when the alternative syntax is more convenient? (.x and .y are more convenient most of the time, but treating them as arrays will be more convenient for operations between vectors and matrices)

I know this is trivial shit but I want to get it right before I go any further.

>>42
well LE SAGER GUY, >>41 is right and you have no correct arguments against. faggot.