add preproc and proc

main.go

@@ -23,7 +23,7 @@ func reader(in string) (io.Reader, error) {
 
 func writer(out string) (io.Writer, error) {
 	if out != "" {
-		file, err := os.Open(out)
+		file, err := os.Create(out)
 		if err != nil {
 			return nil, err
 		}
@@ -42,7 +42,7 @@ type ir struct {
 	r io.Reader
 }
 
-func NewIr(r io.Reader) *ir {
+func InputStream(r io.Reader) *ir {
 	return &ir{r: r}
 }
 
@@ -62,7 +62,7 @@ type ow struct {
 	w io.Writer
 }
 
-func NewOw(w io.Writer) *ow {
+func OutputStream(w io.Writer) *ow {
 	return &ow{w: w}
 }
 
@@ -75,8 +75,8 @@ func (m *ow) Input(data chan []byte) {
 func main() {
 	var in, out string
 
-	flag.StringVar(&in, "in", "", "specify a .md (Markdown) file to read from, otherwise stdin (default)")
-	flag.StringVar(&out, "out", "", "specify a .gmi (gemtext) file to write to, otherwise stdout (default)")
+	flag.StringVar(&in, "f", "", "specify a .md (Markdown) file to read from, otherwise stdin (default)")
+	flag.StringVar(&out, "o", "", "specify a .gmi (gemtext) file to write to, otherwise stdout (default)")
 	flag.Parse()
 
 	r, err := reader(in)
@@ -91,9 +91,11 @@ func main() {
 		os.Exit(1)
 	}
 
-	source := NewIr(r)
-	sink := NewOw(w)
-	preproc := NewParser()
+	source := InputStream(r)
+	sink := OutputStream(w)
+	preproc := NewPreproc()
+	proc := NewProc()
 
-	sink.Input(preproc.Parse(source.Output()))
+	//sink.Input(preproc.Process(source.Output()))
+	sink.Input(proc.Process(preproc.Process(source.Output())))
 }

preproc.go

@@ -14,11 +14,11 @@ type fsm struct {
 	pending []byte
 }
 
-func NewParser() *fsm {
+func NewPreproc() *fsm {
 	return &fsm{}
 }
 
-func (m *fsm) Parse(in chan []byte) chan []byte {
+func (m *fsm) Process(in chan []byte) chan []byte {
 	m.out = make(chan []byte)
 	go func() {
 		for m.state = normal; m.state != nil; {
@@ -90,7 +90,6 @@ func normal(m *fsm, data []byte) stateFn {
 		return paragraph
 	}
 	// TODO
-	// find links
 	// collapse lists
 	m.out <- append(data, '\n')
 
@@ -124,8 +123,3 @@ func paragraph(m *fsm, data []byte) stateFn {
 	m.buffer = append(m.buffer, []byte(" ")...)
 	return paragraph
 }
-
-func link(m *fsm, data []byte) stateFn {
-
-	return link
-}

proc.go

@@ -0,0 +1,52 @@
+package main
+
+// state function
+type stateFn2 func(*proc, []byte) stateFn2
+
+// state machine
+type proc struct {
+	state stateFn2
+	out   chan []byte
+
+	// combining multiple input lines
+	buffer []byte
+	// if we have a termination rule to abide, e.g. implied code fences
+	pending []byte
+}
+
+func NewProc() *proc {
+	return &proc{}
+}
+
+func (m *proc) Process(in chan []byte) chan []byte {
+	m.out = make(chan []byte)
+	go func() {
+		for m.state = line; m.state != nil; {
+			b, ok := <-in
+			if !ok {
+				m.flush()
+				close(m.out)
+				m.state = nil
+				continue
+			}
+			m.state = m.state(m, b)
+		}
+	}()
+	return m.out
+}
+
+func (m *proc) flush() {
+	if len(m.pending) > 0 {
+		m.out <- append(m.pending, '\n')
+		m.pending = m.pending[:0]
+	}
+}
+
+func line(m *proc, data []byte) stateFn2 {
+	// TODO
+	// find links
+	// collapse lists
+	m.out <- data
+
+	return line
+}