package main
import (
"fmt"
"reflect"
"strings"
)
type Inner struct {
N int
}
type S struct {
Inner
NamedInner Inner
PtrInner *Inner
unexported int
N int8
}
func indentStr(level int) string {
return strings.Repeat(" ", level)
}
// if sf is not nil, this is a field of a struct
func describeStruct(level int, rv reflect.Value, sf *reflect.StructField) {
structType := rv.Type()
nFields := rv.NumField()
typ := rv.Type()
if sf == nil {
fmt.Printf("%sstruct %s, %d field(s), size: %d bytes\n", indentStr(level), structType.Name(), nFields, typ.Size())
} else {
fmt.Printf("%sname: '%s' type: 'struct %s', offset: %d, %d field(s), size: %d bytes, embedded: %v\n", indentStr(level), sf.Name, structType.Name(), sf.Offset, nFields, typ.Size(), sf.Anonymous)
}
for i := 0; i < nFields; i++ {
fv := rv.Field(i)
sf := structType.Field(i)
describeType(level+1, fv, &sf)
}
}
// if sf is not nil, this is a field of a struct
func describeType(level int, rv reflect.Value, sf *reflect.StructField) {
switch rv.Kind() {
case reflect.Int, reflect.Int8:
// in real code we would handle more primitive types
i := rv.Int()
typ := rv.Type()
if sf == nil {
fmt.Printf("%stype: '%s', value: '%d'\n", indentStr(level), typ.Name(), i)
} else {
fmt.Printf("%s name: '%s' type: '%s', value: '%d', offset: %d, size: %d\n", indentStr(level), sf.Name, typ.Name(), i, sf.Offset, typ.Size())
}
case reflect.Ptr:
fmt.Printf("%spointer\n", indentStr(level))
describeType(level+1, rv.Elem(), nil)
case reflect.Struct:
describeStruct(level, rv, sf)
}
}
func main() {
var s S
describeType(0, reflect.ValueOf(s), nil)
}
