Initial commit

03-packages-and-scopes/02-scopes/01-scopes/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+// file scope
+import "fmt"
+
+// package scope
+const ok = true
+
+// package scope
+func main() { // block scope starts
+
+	var hello = "Hello"
+
+	// hello and ok are visible here
+	fmt.Println(hello, ok)
+
+} // block scope ends

03-packages-and-scopes/02-scopes/02-block-scope/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+func nope() { // block scope starts
+
+	// hello and ok are only visible here
+	const ok = true
+	var hello = "Hello"
+
+	_ = hello
+} // block scope ends
+
+func main() { // block scope starts
+
+	// hello and ok are not visible here
+
+	// ERROR:
+	// fmt.Println(hello, ok)
+
+} // block scope ends

03-packages-and-scopes/02-scopes/03-nested-scope/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+// I didn't talk about this in a lecture
+// As a side-note, I wanted to put it here
+// Please review it.
+
+var declareMeAgain = 10
+
+func nested() { // block scope starts
+
+	// declares the same variable
+	// they both can exist together
+	// this one only belongs to this scope
+	// package's variable is still intact
+	var declareMeAgain = 5
+	fmt.Println("inside nope:", declareMeAgain)
+
+} // block scope ends
+
+func main() { // block scope starts
+
+	fmt.Println("inside main:", declareMeAgain)
+
+	nested()
+
+	// package-level declareMeAgain isn't effected
+	// from the change inside the nested func
+	fmt.Println("inside main:", declareMeAgain)
+
+} // block scope ends

03-packages-and-scopes/02-scopes/04-package-scope/bye.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func bye() {
+	fmt.Println("Bye!")
+}

03-packages-and-scopes/02-scopes/04-package-scope/hey.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func hey() {
+	fmt.Println("Hey!")
+}

03-packages-and-scopes/02-scopes/04-package-scope/main.go

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+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Println("Hello!")
+
+	// two files belong to the same package
+	// calling `bye()` of bye.go here
+	bye()
+}
+
+// EXERCISE: Remove the comments from the below function
+//           And analyze the error message
+
+// func bye() {
+// 	fmt.Println("Bye!")
+// }
+
+// ***** EXPLANATION *****
+//
+// ERROR: "bye" function "redeclared"
+//        in "this block"
+//
+// "this block" means = "main package"
+//
+// "redeclared" means = you're using the same name
+//   in the same scope again
+//
+// main package's scope is:
+// all source-code files which are in the same main package