use FieldByName where possible.

R=rsc
DELTA=20  (0 added, 12 deleted, 8 changed)
OCL=31758
CL=31758

src/pkg/datafmt/datafmt.go

@@ -423,11 +423,8 @@ func getField(val reflect.Value, fieldname string) (reflect.Value, int) {
 	styp := sval.Type().(*reflect.StructType);
 
 	// look for field at the top level
-	for i := 0; i < styp.NumField(); i++ {
-		f := styp.Field(i);
-		if f.Name == fieldname {
-			return sval.Field(i), 0;
-		}
+	if field, ok := styp.FieldByName(fieldname); ok {
+		return sval.Field(field.Index), 0;
 	}
 
 	// look for field in anonymous fields

src/pkg/json/struct.go

@@ -184,10 +184,8 @@ func (b *_StructBuilder) Key(k string) Builder {
 	}
 	if v, ok := reflect.Indirect(b.val).(*reflect.StructValue); ok {
 		t := v.Type().(*reflect.StructType);
-		for i := 0; i < t.NumField(); i++ {
-			if t.Field(i).Name == k {
-				return &_StructBuilder{ v.Field(i) }
-			}
+		if field, ok := t.FieldByName(k); ok {
+			return &_StructBuilder{ v.Field(field.Index) }
 		}
 		// Again, case-insensitive.
 		for i := 0; i < t.NumField(); i++ {

src/pkg/template/template.go

@@ -571,11 +571,8 @@ func (st *state) findVar(s string) reflect.Value {
 	data := reflect.Indirect(st.data);
 	typ, ok := data.Type().(*reflect.StructType);
 	if ok {
-		for i := 0; i < typ.NumField(); i++ {
-			f := typ.Field(i);
-			if f.Name == s {
-				return data.(*reflect.StructValue).Field(i)
-			}
+		if field, ok := typ.FieldByName(s); ok {
+			return data.(*reflect.StructValue).Field(field.Index)
 		}
 	}
 	return nil