add HideName option to printer

Author: Leon Huston

repr.go

@@ -105,6 +105,12 @@ func Hide[T any]() Option {
 	}
 }
 
+func HideName(name string) Option {
+	return func(o *Printer) {
+		o.excludeNames[name] = true
+	}
+}
+
 // AlwaysIncludeType always includes explicit type information for each item.
 func AlwaysIncludeType() Option { return func(o *Printer) { o.alwaysIncludeType = true } }
 
@@ -118,18 +124,20 @@ type Printer struct {
 	alwaysIncludeType bool
 	explicitTypes     bool
 	exclude           map[reflect.Type]bool
+	excludeNames      map[string]bool
 	w                 io.Writer
 	useLiterals       bool
 }
 
 // New creates a new Printer on w with the given Options.
 func New(w io.Writer, options ...Option) *Printer {
 	p := &Printer{
-		w:         w,
-		indent:    "  ",
-		omitEmpty: true,
-		omitZero:  true,
-		exclude:   map[reflect.Type]bool{},
+		w:            w,
+		indent:       "  ",
+		omitEmpty:    true,
+		omitZero:     true,
+		exclude:      map[reflect.Type]bool{},
+		excludeNames: map[string]bool{},
 	}
 	for _, option := range options {
 		option(p)
@@ -280,6 +288,9 @@ func (p *Printer) reprValue(seen map[reflect.Value]bool, v reflect.Value, indent
 				if p.exclude[t.Type] {
 					continue
 				}
+				if p.excludeNames[t.Name] {
+					continue
+				}
 				f := v.Field(i)
 				ft := f.Type()
 				// skip private fields

repr_test.go

@@ -278,7 +278,7 @@ func TestReprPrivateBytes(t *testing.T) {
 }
 
 func TestReprAnyNumeric(t *testing.T) {
-	var value = []any{float64(123)}
+	value := []any{float64(123)}
 	equal(t, "[]any{float64(123)}", String(value))
 }
 
@@ -293,3 +293,12 @@ func TestScalarLiterals(t *testing.T) {
 	d := time.Second
 	equal(t, "time.Duration(1000000000)", String(d, ScalarLiterals()))
 }
+
+func TestHideStructFieldsByName(t *testing.T) {
+	actual := testStruct{
+		S: "str",
+		A: anotherStruct{A: []int{1}},
+	}
+	res := String(actual, HideName("A"))
+	equal(t, `repr.testStruct{S: "str"}`, res)
+}