Hands-On System Programming with Go

Using tags

A structure field carries plenty of information, from the field name and index to its tag:

type StructField struct {    Name string    PkgPath string    Type Type      // field type    Tag StructTag  // field tag string    Offset uintptr // offset within struct, in bytes    Index []int    // index sequence for Type.FieldByIndex    Anonymous bool // is an embedded field}

A reflect.StructField value can be obtained using the reflect.Type methods:

• Field
• FieldByName
• FieldByIndex

They are the same methods used by reflect.Value, but they return different types. The NumField method returns the total number of fields for the structure, allowing us to execute an iteration:

type Person struct {    Name string `json:"name,omitempty" xml:"-"` Surname string `json:"surname,omitempty" ...