Merge branch 'master' of https://github.com/denevell/BlogPosts

Author: denevell

golang-null-nil.md

@@ -0,0 +1,42 @@
+Title: Golang: Understanding 'null' and nil 
+Tags: golang, golang-nil
+
+Golang does not allow NULL, or its version nil, where some languages do.
+
+		package main
+		import "fmt"
+
+		func main() {
+			someRandom := getString()
+			fmt.Println(someRandom)
+		}
+
+		func getString() string {
+			return nil // This WON'T compile
+		}
+
+Because the return of getString is a **value** (and a struct is a value too, incidentally), it cannot be nil. 
+
+This allows us to avoid many NULL pointer errors in other languages.
+
+A 'NULL' pointer error is still possible, however. But only with actual **pointers or references** (a slice is a common example).
+
+		package main
+		import "fmt"
+
+		type SomeStruct struct {
+			name string
+		}
+
+		func main() {
+			s := getSomeStruct()
+			fmt.Println(s.name) // It will crash here
+		}
+
+		func getSomeStruct() *SomeStruct {
+			return nil // This WILL compile
+		}
+
+In this case, since getSomeStruct() returns a pointer, we can return nil. 
+
+And as such if we try to reference the 'name' attribute of the struct we will crash.