Herb Sutter – complex initialisation for a const variable

Herb Sutter provided this handy use of lambdas to initialise a const variable that needs some logic:

const int i = [&]{

    int i = some_default_value;

    if(someConditionIstrue)
    {
        Do some operations and calculate the value of i;
        i = some calculated value;
    }

    return i;

} (); // note: () invokes the lambda!

It requires that the compiler can determine the type of the lambda even though it isn’t a simple return – that’s due to be finalised in C++14 but is supported in some compilers already.