[btown]

Is there any good documentation about contracts? https://en.cppreference.com/w/cpp/language/contracts.html is incredibly confusing - its first displayed example seems to be an edge case where the assertion itself causes a mutation?

https://en.cppreference.com/w/cpp/language/function.html#Fun... is vaguely better, but still quite dense.

IMO the syntax makes things hard for a newcomer to the syntax to understand, which I see as core to any programming language's goals of community.

    double square_root(double num) asserts_pre(num >= 0)

would have been far more self-evident than just

    double square_root(double num) pre(num >= 0)

But I suppose brevity won out.

[steveklabnik]

I believe that https://isocpp.org/files/papers/P2900R14.pdf is the paper, which doesn't mean it's good documentation, as it's meant for modifying the standard. However, in its early sections, it does link to other papers which have more information, and the "proposed wording" section should be where the standardize lives, with the rest of it being context.