parse fences and paragraphs

README.md

@@ -1,6 +1,7 @@
 ## md2gmi
 
-Convert Markdown to Gemini Gemini "gemtext" markup with Go.
+Convert Markdown to Gemini Gemini "gemtext" markup with Go. Working with streams and pipes for UNIX
+like behavior utilizing Go channels.
 
 ### Usage
 

parser.go

@@ -10,10 +10,13 @@ type stateFn func(*fsm, []byte) stateFn
 
 // state machine
 type fsm struct {
-	state stateFn
-	out   io.Writer
-	quit  chan struct{}
-	data  <-chan []byte
+	state  stateFn
+	buffer []byte
+	out    io.Writer
+	quit   chan struct{}
+	data   <-chan []byte
+
+	pending []byte
 }
 
 func NewParser(data <-chan []byte, writer io.Writer, quit chan struct{}) *fsm {
@@ -25,18 +28,51 @@ func NewParser(data <-chan []byte, writer io.Writer, quit chan struct{}) *fsm {
 }
 
 func (m *fsm) Parse() {
-	var buffer []byte
-	for m.state = initial; m.state != nil; {
+	var line []byte
+	for m.state = normal; m.state != nil; {
 		select {
 		case <-m.quit:
+			m.flush()
 			m.state = nil
-		case buffer = <-m.data:
-			m.state = m.state(m, buffer)
+		case line = <-m.data:
+			m.state = m.state(m, line)
 		}
 	}
 }
 
-func initial(m *fsm, data []byte) stateFn {
+func (m *fsm) flush() {
+	if len(m.pending) > 0 {
+		fmt.Fprintf(m.out, string(m.pending)+"\n")
+		m.pending = m.pending[:0]
+	}
+}
+
+func normal(m *fsm, data []byte) stateFn {
+	m.flush()
+	// blank line
+	if len(data) == 0 {
+		fmt.Fprintf(m.out, "\n")
+		return normal
+	}
+	// header
+	if data[0] == '#' {
+		fmt.Fprintf(m.out, string(data)+"\n")
+		return normal
+	}
+	if len(data) >= 3 && string(data[0:3]) == "```" {
+		fmt.Fprintf(m.out, string(data)+"\n")
+		return fence
+	}
+	if len(data) >= 4 && string(data[0:4]) == "    " {
+		fmt.Fprintf(m.out, string("```")+"\n")
+		fmt.Fprintf(m.out, string(data)+"\n")
+		m.pending = []byte("```")
+		return tofence
+	}
+	if data[len(data)-1] != '.' {
+		m.buffer = append(m.buffer, data...)
+		return paragraph
+	}
 	// TODO
 	// find linebreaks
 	// find code fences
@@ -44,5 +80,33 @@ func initial(m *fsm, data []byte) stateFn {
 	// collapse lists
 	fmt.Fprintf(m.out, string(data)+"\n")
 
-	return initial
+	return normal
+}
+
+func fence(m *fsm, data []byte) stateFn {
+	fmt.Fprintf(m.out, string(data)+"\n")
+	if len(data) >= 3 && string(data[0:3]) == "```" {
+		return normal
+	}
+	return fence
+}
+
+func tofence(m *fsm, data []byte) stateFn {
+	if len(data) >= 4 && string(data[0:4]) == "    " {
+		fmt.Fprintf(m.out, string(data)+"\n")
+		return tofence
+	}
+	fmt.Fprintf(m.out, string(data)+"\n")
+	return normal
+}
+
+func paragraph(m *fsm, data []byte) stateFn {
+	if len(data) == 0 || data[len(data)-1] == '.' {
+		m.buffer = append(m.buffer, data...)
+		fmt.Fprintf(m.out, string(m.buffer)+"\n")
+		m.buffer = m.buffer[:0]
+		return normal
+	}
+	m.buffer = append(m.buffer, data...)
+	return paragraph
 }