Change the order of Apply to be more Unixy

Typically the destination is on the left and the src is on the right.

hugolib/site.go

@@ -618,10 +618,13 @@ func (s *Site) WritePublic(path string, content io.Reader) (err error) {
 	}
 
 	if s.Transformer == nil {
-		s.Transformer = &transform.AbsURL{BaseURL: s.Config.BaseUrl}
+		s.Transformer = transform.NewChain(
+			&transform.AbsURL{BaseURL: s.Config.BaseUrl},
+			&transform.NavActive{Section: "tbd"},
+		)
 	}
 	final := new(bytes.Buffer)
-	s.Transformer.Apply(content, final)
+	s.Transformer.Apply(final, content)
 	return s.Target.Publish(path, final)
 }
 

transform/absurl.go

@@ -10,7 +10,7 @@ type AbsURL struct {
 	BaseURL string
 }
 
-func (t *AbsURL) Apply(r io.Reader, w io.Writer) (err error) {
+func (t *AbsURL) Apply(w io.Writer, r io.Reader) (err error) {
 	var tr *htmltran.Transformer
 
 	if tr, err = htmltran.NewFromReader(r); err != nil {

transform/chain.go

@@ -13,11 +13,11 @@ func NewChain(trs ...Transformer) Transformer {
 	return &chain{transformers: trs}
 }
 
-func (c *chain) Apply(r io.Reader, w io.Writer) (err error) {
+func (c *chain) Apply(w io.Writer, r io.Reader) (err error) {
 	in := r
 	for _, tr := range c.transformers {
 		out := new(bytes.Buffer)
-		err = tr.Apply(in, out)
+		err = tr.Apply(out, in)
 		if err != nil {
 			return
 		}

transform/nav.go

@@ -11,7 +11,7 @@ type NavActive struct {
 	AttrName string
 }
 
-func (n *NavActive) Apply(r io.Reader, w io.Writer) (err error) {
+func (n *NavActive) Apply(w io.Writer, r io.Reader) (err error) {
 	var tr *htmltran.Transformer
 
 	if n.Section == "" {

transform/nav_test.go

@@ -37,7 +37,7 @@ func TestDegenerateNoSectionSet(t *testing.T) {
 		out = new(bytes.Buffer)
 	)
 
-	if err := tr.Apply(strings.NewReader(HTML_WITH_NAV), out); err != nil {
+	if err := tr.Apply(out, strings.NewReader(HTML_WITH_NAV)); err != nil {
 		t.Errorf("Unexpected error in NavActive.Apply: %s", err)
 	}
 
@@ -49,7 +49,7 @@ func TestDegenerateNoSectionSet(t *testing.T) {
 func TestSetNav(t *testing.T) {
 	tr := &NavActive{Section: "section_2"}
 	out := new(bytes.Buffer)
-	if err := tr.Apply(strings.NewReader(HTML_WITH_NAV), out); err != nil {
+	if err := tr.Apply(out, strings.NewReader(HTML_WITH_NAV)); err != nil {
 		t.Errorf("Unexpected error in Apply() for NavActive: %s", err)
 	}
 

transform/post.go

@@ -5,5 +5,5 @@ import (
 )
 
 type Transformer interface {
-	Apply(io.Reader, io.Writer) error
+	Apply(io.Writer, io.Reader) error
 }

transform/posttrans_test.go

@@ -38,7 +38,7 @@ var abs_url_tests = []test {
 func apply(t *testing.T, tr Transformer, tests []test) {
 	for _, test := range tests {
 		out := new(bytes.Buffer)
-		err := tr.Apply(strings.NewReader(test.content), out)
+		err := tr.Apply(out, strings.NewReader(test.content))
 		if err != nil {
 			t.Errorf("Unexpected error: %s", err)
 		}