Guide: Standard input

Another option is to explicitly defer it:
```rust
// Cheap error handling which is quite complicated and
// will not be explained until Section 7.4
// Basically, use normally and call "Error!" when it errors
.ok().expect("Error!");
```

_Accelerated C++_ does that often and I find it really helpful. They never lie, they explain enough for the section, and they tell you where to look if you want more info (will be easier to link when the guides finished though...). _Accelerated C++_ is quite terse and dry probably though.

Examples:

> Its [`<<` in `cout << "Hi"`] right operand is a string literal, which has a mysterious type that we shall not even discuss until pg. 176
> --- Accelerated C++ pg. 4

> The type of a string literal [compared with a character literal] is much more complicated and we shall not explain it until pg. 176.
> --- Accelerated C++ pg. 14

> The details of [`istream`] turn out to be complicated enough that we won't discuss it in detail until pg. 222
> --- Accelerated C++ pg. 40