1 files changed, 278 insertions, 0 deletions
diff --git a/document.go b/document.go
new file mode 100644
index 0000000..b5cdbe5
--- /dev/null
+++ b/document.go
@@ -0,0 +1,278 @@
+// Package cnm implements CNM document parsing and composition.
+package cnm // import "contnet.org/lib/cnm-go"
+
+import (
+	"bufio"
+	"io"
+	"path"
+	"strings"
+)
+
+// Document represents a CNM document.
+type Document struct {
+	// Title is the document title (top-level "title" block).
+	Title string
+
+	// Links is a list of document-level hyperlinks (top-level "links" block).
+	Links []Link
+
+	// Site is a sitemap (top-level "site" block).
+	Site Site
+
+	// Content is the document content (top-level "content" block).
+	Content *ContentBlock
+}
+
+// ParseDocument parses a CNM document from r.
+func ParseDocument(r io.Reader) (doc *Document, err error) {
+	p := NewParser(r)
+	doc = &Document{}
+	err = p.Next()
+	for err == nil {
+		token := p.Block()
+		if err = p.Next(); err != nil {
+			break
+		}
+		if blk, ok := token.(*TokenBlock); ok {
+			switch blk.Name {
+			case "title":
+				err = doc.parseTitle(p, blk)
+			case "links":
+				err = doc.parseLinks(p, blk)
+			case "site":
+				err = doc.Site.parse(p, blk)
+			case "content":
+				if doc.Content == nil {
+					doc.Content = &ContentBlock{name: "content"}
+				}
+				err = doc.Content.parse(p, blk)
+			default:
+				// discard lines inside this block
+				for err == nil {
+					if !p.Empty() && p.Indent() <= blk.Indent() {
+						break
+					}
+					err = p.Next()
+				}
+			}
+		}
+	}
+	if err == io.EOF {
+		err = nil
+	}
+	return
+}
+
+func (doc *Document) Write(w io.Writer) error {
+	bw := bufio.NewWriter(w)
+	if doc.Title != "" {
+		if err := writeIndent(bw, "title", 0); err != nil {
+			return err
+		}
+		if err := writeIndent(bw, Escape(doc.Title), 1); err != nil {
+			return err
+		}
+	}
+	if len(doc.Links) > 0 {
+		if err := writeIndent(bw, "links", 0); err != nil {
+			return err
+		}
+		for _, link := range doc.Links {
+			if err := link.WriteIndent(bw, 1); err != nil {
+				return err
+			}
+		}
+	}
+	if len(doc.Site.Children) > 0 {
+		if err := writeIndent(bw, "site", 0); err != nil {
+			return err
+		}
+		for _, site := range doc.Site.Children {
+			if err := site.WriteIndent(bw, 1); err != nil {
+				return err
+			}
+		}
+	}
+	if doc.Content != nil {
+		if err := doc.Content.WriteIndent(bw, 0); err != nil {
+			return err
+		}
+	}
+	return bw.Flush()
+}
+
+func (doc *Document) parseTitle(p *Parser, block *TokenBlock) (err error) {
+	s, err := getSimpleText(p, block)
+	if doc.Title == "" {
+		doc.Title = s
+	} else {
+		doc.Title += " " + s
+	}
+	return
+}
+
+func (doc *Document) parseLinks(p *Parser, block *TokenBlock) (err error) {
+	for err == nil {
+		if !p.Empty() && p.Indent() <= block.Indent() {
+			break
+		}
+
+		token := p.Block()
+		if blk, ok := token.(*TokenBlock); ok {
+			if blk.Name == "" {
+				err = parseUnknown(p, blk)
+			} else {
+				link := Link{
+					URL:  blk.Name,
+					Name: strings.Join(blk.Args, " "),
+				}
+				doc.Links = append(doc.Links, link)
+				if err = p.Next(); err != nil {
+					break
+				}
+				doc.Links[len(doc.Links)-1].Description, err = getSimpleText(p, blk)
+			}
+		}
+	}
+	return
+}
+
+func getSimpleText(p *Parser, block *TokenBlock) (s string, err error) {
+	for err == nil {
+		if !p.Empty() && p.Indent() <= block.Indent() {
+			break
+		}
+
+		token := p.SimpleText()
+		if text, ok := token.(*TokenSimpleText); ok && text.Text != "" {
+			if s == "" {
+				s = text.Text
+			} else {
+				s += " " + text.Text
+			}
+		}
+
+		err = p.Next()
+	}
+	return
+}
+
+// Link represents a document-level hyperlink in the "links" top-level block.
+type Link struct {
+	// URL is the hyperlink URL.
+	URL string
+
+	// Name is the hyperlink text.
+	Name string
+
+	// Description is the description of the hyperlink.
+	Description string
+}
+
+// WriteIndent writes the link URL, name and description indented by n tabs.
+func (link Link) WriteIndent(w io.Writer, n int) error {
+	s := Escape(link.URL)
+	if link.Name != "" {
+		s += " " + Escape(link.Name)
+	}
+	if err := writeIndent(w, s, n); err != nil {
+		return err
+	}
+	if link.Description != "" {
+		if err := writeIndent(w, Escape(link.Description), n+1); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Site represents a node in the sitemap in the "site" top-level block.
+type Site struct {
+	// Path is the node's path fragment.
+	Path string
+
+	// Name is the node's name.
+	Name string
+
+	// Children are the nodes below this node.
+	Children []Site
+}
+
+// WriteIndent writes the sitemap indented by n tabs.
+func (site Site) WriteIndent(w io.Writer, n int) error {
+	s := Escape(site.Path)
+	if site.Name != "" {
+		s += " " + Escape(site.Name)
+	}
+	if err := writeIndent(w, s, n); err != nil {
+		return err
+	}
+	for _, ch := range site.Children {
+		if err := ch.WriteIndent(w, n+1); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (site *Site) parse(p *Parser, block *TokenBlock) (err error) {
+	for err == nil {
+		if !p.Empty() && p.Indent() <= block.Indent() {
+			break
+		}
+
+		token := p.Block()
+		if blk, ok := token.(*TokenBlock); ok {
+			if blk.Name == "" {
+				err = parseUnknown(p, blk)
+			} else {
+				s := Site{
+					Path: strings.Trim(path.Clean(blk.Name), "/"),
+					Name: strings.Join(blk.Args, " "),
+				}
+				site.Children = append(site.Children, s)
+				if err = p.Next(); err != nil {
+					break
+				}
+				err = site.Children[len(site.Children)-1].parse(p, blk)
+			}
+		} else {
+			err = p.Next()
+		}
+	}
+	return
+}
+
+func parseUnknown(p *Parser, block *TokenBlock) (err error) {
+	err = p.Next()
+	for err == nil {
+		if !p.Empty() && p.Indent() <= block.Indent() {
+			break
+		}
+		// discard lines inside this block
+		err = p.Next()
+	}
+	return
+}
+
+func writeIndent(w io.Writer, s string, depth int) error {
+	const tabs = "\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t"
+
+	if s == "" {
+		_, err := w.Write([]byte{'\n'})
+		return err
+	}
+	if depth == 0 {
+		_, err := w.Write([]byte(s + "\n"))
+		return err
+	}
+
+	var ind string
+	if depth <= len(tabs) {
+		ind = tabs[:depth]
+	} else {
+		ind = strings.Repeat("\t", depth)
+	}
+	_, err := w.Write([]byte(ind + s + "\n"))
+	return err
+}