structure: rename IsZero to HasZero

This reflect the intention of this function much better. Suggestion is
from golang-nuts.

README.md

@@ -51,9 +51,9 @@ n := structure.Name(s)
 // => true
 h := structure.Has(s, "Enabled")
 
-// Check if the fields of a struct is initialized or not.
-if !structure.IsZero(s) {
-    fmt.Println("s is initialized")
+// Check if any field of a struct is initialized or not.
+if structure.HasZero(s) {
+    fmt.Println("s has a zero value field")
 }
 
 // Check if it's a struct or a pointer to struct

structure.go

@@ -80,22 +80,22 @@ func Values(s interface{}) []interface{} {
 
 }
 
-// IsZero returns true if any field in a struct is not initialized and has the
-// zero default value. A struct tag with the content of "-" ignores the checking
-// of that particular field. Example:
+// HasZero returns true if a field in a struct is not initialized (zero value).
+// A struct tag with the content of "-" ignores the checking of that particular
+// field. Example:
 //
 //   // Field is ignored by this package.
 //   Field bool `structure:"-"`
 //
 // Note that only exported fields of a struct can be accessed, non exported
 // fields  will be neglected. It panics if s's kind is not struct.
-func IsZero(s interface{}) bool {
+func HasZero(s interface{}) bool {
 	v, fields := strctInfo(s)
 
 	for i := range fields {
 		val := v.Field(i)
 		if IsStruct(val.Interface()) {
-			ok := IsZero(val.Interface())
+			ok := HasZero(val.Interface())
 			if ok {
 				return true
 			}
@@ -221,21 +221,6 @@ func strctInfo(s interface{}) (reflect.Value, []reflect.StructField) {
 	return v, f
 }
 
-func strctType(s interface{}) reflect.Type {
-	t := reflect.TypeOf(s)
-
-	// if pointer get the underlying element≤
-	if t.Kind() == reflect.Ptr {
-		t = t.Elem()
-	}
-
-	if t.Kind() != reflect.Struct {
-		panic("not struct")
-	}
-
-	return t
-}
-
 func strctVal(s interface{}) reflect.Value {
 	v := reflect.ValueOf(s)
 

structure_example_test.go

@@ -96,7 +96,7 @@ func ExampleFields() {
 	// Fields: [Name LastAccessed Number]
 }
 
-func ExampleIsZero() {
+func ExampleHasZero() {
 	// Let's define an Access struct. Note that the "Enabled" field is not
 	// going to be checked because we added the "structure" tag to the field.
 	type Access struct {
@@ -110,7 +110,7 @@ func ExampleIsZero() {
 	a := &Access{
 		LastAccessed: time.Now(),
 	}
-	isZeroA := IsZero(a)
+	hasZeroA := HasZero(a)
 
 	// Name and Number is initialized.
 	b := &Access{
@@ -118,10 +118,10 @@ func ExampleIsZero() {
 		LastAccessed: time.Now(),
 		Number:       12345,
 	}
-	isZeroB := IsZero(b)
+	hasZeroB := HasZero(b)
 
-	fmt.Printf("%#v\n", isZeroA)
-	fmt.Printf("%#v\n", isZeroB)
+	fmt.Printf("%#v\n", hasZeroA)
+	fmt.Printf("%#v\n", hasZeroB)
 	// Output:
 	// true
 	// false

structure_test.go

@@ -345,7 +345,7 @@ func TestFields_Anonymous(t *testing.T) {
 	}
 }
 
-func TestIsZero(t *testing.T) {
+func TestHasZero(t *testing.T) {
 	var T = struct {
 		A string
 		B int
@@ -356,9 +356,9 @@ func TestIsZero(t *testing.T) {
 		B: 2,
 	}
 
-	ok := IsZero(T)
+	ok := HasZero(T)
 	if !ok {
-		t.Error("IsZero should return true because A and B are initialized.")
+		t.Error("HasZero should return true because A and B are initialized.")
 	}
 
 	var X = struct {
@@ -368,9 +368,9 @@ func TestIsZero(t *testing.T) {
 		A: "a-value",
 	}
 
-	ok = IsZero(X)
+	ok = HasZero(X)
 	if !ok {
-		t.Error("IsZero should return true because A is initialized")
+		t.Error("HasZero should return true because A is initialized")
 	}
 
 	var Y = struct {
@@ -381,13 +381,13 @@ func TestIsZero(t *testing.T) {
 		B: 123,
 	}
 
-	ok = IsZero(Y)
+	ok = HasZero(Y)
 	if ok {
-		t.Error("IsZero should return false because A and B is initialized")
+		t.Error("HasZero should return false because A and B is initialized")
 	}
 }
 
-func TestIsZero_Nested(t *testing.T) {
+func TestHasZero_Nested(t *testing.T) {
 	type A struct {
 		Name string
 		D    string
@@ -400,13 +400,13 @@ func TestIsZero_Nested(t *testing.T) {
 	}
 	b := &B{A: a, C: 123}
 
-	ok := IsZero(b)
+	ok := HasZero(b)
 	if !ok {
-		t.Error("IsZero should return true because D is not initialized")
+		t.Error("HasZero should return true because D is not initialized")
 	}
 }
 
-func TestIsZero_Anonymous(t *testing.T) {
+func TestHasZero_Anonymous(t *testing.T) {
 	type A struct {
 		Name string
 		D    string
@@ -420,9 +420,9 @@ func TestIsZero_Anonymous(t *testing.T) {
 	b := &B{C: 123}
 	b.A = a
 
-	ok := IsZero(b)
+	ok := HasZero(b)
 	if !ok {
-		t.Error("IsZero should return false because D is not initialized")
+		t.Error("HasZero should return false because D is not initialized")
 	}
 }