CODEWITHSUNDEEP
c++c++17
Antoine Morrier
Antoine Morrier

Reputation: 4078

Structured Bindings : loop over deque of tuple

I just installed the last version of Visual Studio and I have this deque of tuple :

using InstancesOfOneObject = std::tuple<DrawCmd, std::deque<bool>, std::deque<glm::mat4>>;
std::deque<InstancesOfOneObject> mInstancesByObject;

After, I want to traverse this deque with a for ranged loop :

for (const auto &[cmd, validites, matrices] : mInstancesByObject)

However, that does not work, but :

for (const auto &instance : mInstancesByObject) {
    const auto &[cmd, validities, matrices] = instance;

works well.

Is it normal? Is there a way to use something close to the first idea?

Upvotes: 0

Views: 365

Answers (1)

Barry
Barry

Reputation: 303457

The only difference between:

for (const auto &[cmd, validites, matrices] : mInstancesByObject) { ... }

and:

for (const auto &instance : mInstancesByObject) {
    const auto &[cmd, validities, matrices] = instance;
    ...
}

is that the latter allows you to still access instance whereas in the former it's an unnamed object. They are otherwise equivalent. If the former doesn't compile, you should file a bug with that compiler.

Upvotes: 9

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