Merge branch 'master' into master

README.md

@@ -16,7 +16,7 @@ I'd like to take a few sentences to clarify my stance on `gofmt` because there a
 ## Table of Contents
 * [Introduction to Clean Code](#Introduction-to-Clean-Code)
     * [Test-Driven Development](#Test-Driven-Development)
-    * [Naming Conventions](#Naming)
+    * [Naming Conventions](#Naming-Conventions)
     * * [Comments](#Comments)
     	* [Function Naming](#Function-Naming)
     	* [Variable Naming](#Variable-Naming)
@@ -33,7 +33,7 @@ I'd like to take a few sentences to clarify my stance on `gofmt` because there a
     * [Pointers in Go](#Pointers-in-Go)
     * [Closures Are Function Pointers](#Closures-are-Function-Pointers)
     * [Interfaces in Go](#Interfaces-in-Go)
-    * [The empty `interface{}`](#The-empty-`interface{}`)
+    * [The empty `interface{}`](#The-Empty-interface)
 * [Summary](#Summary)
 
 ## Introduction to Clean Code
@@ -102,7 +102,7 @@ Of course, this was a relatively trivial example. Writing clear and expressive c
 
 #### Function Naming
 
-Let's now move on to function naming conventions. The general rule here is really simple: The more specific the function, the more general its name. In other words,  we want to start with a very broad and short function name, such as `Run` or `Parse`, that describes the general functionality. Let's imagine that we are creating a configuration parser. Following this naming convention, our top level of abstraction might look something like the following:
+Let's now move on to function naming conventions. The general rule here is really simple: the more specific the function, the more general its name. In other words, we want to start with a very broad and short function name, such as `Run` or `Parse`, that describes the general functionality. Let's imagine that we are creating a configuration parser. Following this naming convention, our top level of abstraction might look something like the following:
 
 ```go
 func main() {
@@ -226,7 +226,7 @@ func GetItem(ctx context.Context, json []bytes) (Item, error) {
         return NullItem, err
     }
     if !GetUserFromContext(ctx).IsAdmin() {
-	      return NullItem, ErrInsufficientPrivliges
+	      return NullItem, ErrInsufficientPrivileges
     }
     return db.GetItem(order.ItemID)
 }
@@ -488,7 +488,7 @@ func main() {
 
 After our refactor, `val` is no longer modified, and the scope has been reduced. Again, keep in mind that these functions are very simple. Once this kind of code style becomes a part of larger, more complex systems, it can be impossible to figure out why errors are occurring. We don't want this to happen—not only because we generally dislike software errors but also because it's disrespectful to our colleagues, and ourselves; we are potentially wasting each others' time having to debug this type of code. Developers need to take responsibility for their own code rather than blaming these issues on the variable declaration syntax of a particular language like Go.
 
-On a side not, if the `// do something else` part is another attempt to mutate the `val` variable, we should extract that logic out as its own self-contained function, as well as the previous part of it. This way, instead of expanding the mutable scope of our variables, we can just return a new value:
+On a side note, if the `// do something else` part is another attempt to mutate the `val` variable, we should extract that logic out as its own self-contained function, as well as the previous part of it. This way, instead of expanding the mutable scope of our variables, we can just return a new value:
 
 ```go
 func getVal(num int) (string, error) {
@@ -626,6 +626,7 @@ This section focuses less on the generic aspects of writing clean Go code and mo
 ### Return Values
 
 #### Returning Defined Errors
+
 We'll start things off nice and easy by describing a cleaner way to return errors. As we discussed earlier, our main goal with writing clean code is to ensure readability, testability, and maintainability of the codebase. The technique for returning errors that we'll discuss here will achieve all three of those goals with very little effort.
 
 Let's consider the normal way to return a custom error. This is a hypothetical example taken from a thread-safe map implementation that we've named `Store`:
@@ -758,7 +759,7 @@ func NewErrorDetails(err error, details ...interface{}) ErrorDetails {
 }
 
 func (err *errDetails) Error() string {
-    return fmt.Sprintf("%v: %v", err.details)
+    return fmt.Sprintf("%v: %v", err.errtype, err.details)
 }
 
 func (err *errDetails) Type() error {
@@ -1255,7 +1256,7 @@ func InsertItemHandler(w http.ResponseWriter, r *http.Request) {
 
 All the *less elegant* code, is contained within the  `Decode` function. Developers using this functionality, therefore, won't have to worry about reflection or casting of types. We just have to worry about providing a pointer to a concrete type. This is good, because the `Decode()` function is, technically, returning a concrete type. We are passing in our `Item` value, which will be populated from body of the http request and we won't have to deal with the potential risks of handling the `interface{}` value.
 
-However, even when using the empty `interface{}` with good practices, we still have some issues. If we pass a JSON string that has nothing to do with our `Item` type, but is still valid son, we still won't receive an error. Our `item` variable will just be left with the default values. So, while we don't have to worry about reflection and casting errors, we will still have to make sure that the message sent from our client is a valid `Item` type. However, as of writing this document, there is no simple / good way to implement these type of generic decoders, without using the empty `interface{}` type. 
+However, even when using the empty `interface{}` with good practices, we still have some issues. If we pass a JSON string that has nothing to do with our `Item` type, but is still valid json, we still won't receive an error. Our `item` variable will just be left with the default values. So, while we don't have to worry about reflection and casting errors, we will still have to make sure that the message sent from our client is a valid `Item` type. However, as of writing this document, there is no simple / good way to implement these type of generic decoders, without using the empty `interface{}` type. 
 
 The problem with this, is that we are leaning towards using Go (a statically typed language) as a dynamically typed language. This becomes even clearer, when looking at poor implementations of the `interface{}` type. The most common example of this, comes from developers trying to implement a generic store / list of some sort. Let's look at an example, trying to implement a generic HashMap package, which can store any type, using the `interface{}`.