Type assertion, aliasing and conversion in Go

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In Go, type assertion is used to extract the value of an interface at runtime, similar to type casting in other languages. Type aliasing is used to create a new type from an existing type. Type conversion is used to convert a value from one type to another.

func main() {
	type str string     // type aliasing - a new type is created from an existing type (string)


	var str1 interface{} = "hello"
	var str2 str = str("hello") // type conversion - converting a value from one type (string) to another (str)
	var str3 interface{} = str("hello")

	fmt.Println(str1.(string)) // output: hello; type assertion - extracting the value of an interface at runtime

	fmt.Println(str2) // output: hello

	fmt.Println(str3.(str)) // output: hello

	_, isStr := str1.(str) // type assertion but with second return value to check if the assertion is successful
	fmt.Println(isStr) // output: false; str1 is of type string, not str

	_, isString := str3.(string)
	fmt.Println(isString) // output: false; str3 is of type str, not string

}