README

Reflection - Standard Library

Reflection is the ability to inspect a value to derive type or other meta-data. Reflection can give our program incredible flexibility to work with data of different types or create values on the fly. Reflection is critical for the encoding and decoding of data.

Notes

The reflection package allows us to inspect our types.
We can add "tags" to our struct fields to store and use meta-data.
Encoding package leverages reflection and we can as well.

Links

The Laws of Reflection - Rob Pike

Code Review

Interfaces

Example shows how to reflect over a struct type value that is stored inside an interface value.
Struct Types (Go Playground)

Example shows how to reflect over a slice of struct type values that are stored inside an interface value.
Slices (Go Playground)

Example shows how to reflect over a map of struct type values that are stored inside an interface value.
Maps (Go Playground)

Example shows how to reflect over a struct type pointer that is stored inside an interface value.
Pointers (Go Playground)

Inspection / Decoding

Example shows how to inspect a structs fields and display the field name, type and value.
Struct Types (Go Playground)

Example shows how to use reflection to decode an integer.
Integers (Go Playground)

Exercises

Exercise 1

Declare a struct type that represents a request for a customer invoice. Include a CustomerID and InvoiceID field. Define tags that can be used to validate the request. Define tags that specify both the length and range for the ID to be valid. Declare a function named validate that accepts values of any type and processes the tags. Display the results of the validation.

Template (Go Playground) | Answer (Go Playground)

All material is licensed under the Apache License Version 2.0, January 2004.