error_handling.slide

* Error handling

Multiple function return values inform the design for handling errors.

Go has no `try-catch` control structures for exceptions.
Return `error` instead: built-in interface type that can "stringify" itself:

	type error interface { Error() string }

Clear and simple.

Philosophy:

Forces you think about errors—and deal with them—when they arise.
Errors are _normal_. Errors are _not_exceptional_.
Use the existing language to compute based on them.
Don't need a sublanguage that treats them as exceptional.

Result is better code (if more verbose).
(OK, not all errors are normal. But most are.)