C++ operator sugar - a C++ way of looping through array

[cztomczak]

Hi,

The C++ wrapper is great, but I'm missing one thing: a way to loop through array in a c++ fool-proof way. I know that I can do this:

json_value arr = (*settings)["web_server"]["cgi_extensions"];
if (arr.type == json_array) {
    int length = arr.u.array.length;
    for (int i = 0; i < length; i++) {
    ...
    }
}

But, a newbie might forget the type checking and just go with:

json_value arr = (*settings)["web_server"]["cgi_extensions"];
int length = arr.u.array.length;
for (int i = 0; i < length; i++) {
...
}

If someone makes a mistake in the json file, so that array is missing or becomes a string, then this code will crash the application.

I love the C++ wrapper mostly that it is fool-proof, I can reference to a non-existing key and it just returns an empty string, I will mistake the types and it will just return 0, nothing bad happens. But when it comes to looping through arrays it's easy to make a mistake, I've done it already and I'm a little scared of writing such code.

What I'm looking for is some method like GetArrayLength() that will return array length or 0 when value is not an array.

Czarek.

[LB--]

I added support for C++11 range-based for-loops in #21 but I wasn't able to make it do a type check because of the nested class structure preventing access to the type member variable. If I could somehow access type, I could return nullptr for both begin and end for the wrong type, thus not looping at all, but I don't know how to access type.

[jamesamcl]

@LB-- Hmm. You could access type by subtracting the offset of the nested struct from its address to obtain a json_value pointer?