From 539b27a6242239ab88f86e8756318cfc9b28ee74 Mon Sep 17 00:00:00 2001
From: Brian Goff <cpuguy83@gmail.com>
Date: Fri, 1 Aug 2014 22:54:21 -0400
Subject: [PATCH] Add titleblock support

---
 block.go      | 41 ++++++++++++++++++++++++++++++++++++-----
 block_test.go | 16 ++++++++++++++++
 html.go       |  8 ++++++++
 latex.go      |  4 ++++
 markdown.go   |  2 ++
 5 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/block.go b/block.go
index c992d43..d21a0e6 100644
--- a/block.go
+++ b/block.go
@@ -13,9 +13,7 @@
 
 package blackfriday
 
-import (
-	"bytes"
-)
+import "bytes"
 
 // Parse block-level data.
 // Note: this function and many that it calls assume that
@@ -56,6 +54,20 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 			}
 		}
 
+		// title block
+		//
+		// % stuff
+		// % more stuff
+		// % even more stuff
+		if p.flags&EXTENSION_TITLEBLOCK != 0 {
+			if data[0] == '%' {
+				if i := p.titleBlock(out, data, true); i > 0 {
+					data = data[i:]
+					continue
+				}
+			}
+		}
+
 		// blank lines.  note: returns the # of bytes to skip
 		if i := p.isEmpty(data); i > 0 {
 			data = data[i:]
@@ -190,13 +202,13 @@ func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
 	if p.flags&EXTENSION_HEADER_IDS != 0 {
 		j, k := 0, 0
 		// find start/end of header id
-		for j = i; j < end - 1 && (data[j] != '{' || data[j+1] != '#'); j++ {
+		for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
 		}
 		for k = j + 1; k < end && data[k] != '}'; k++ {
 		}
 		// extract header id iff found
 		if j < end && k < end {
-			id = string(data[j+2:k])
+			id = string(data[j+2 : k])
 			end = j
 			skip = k + 1
 			for end > 0 && data[end-1] == ' ' {
@@ -256,6 +268,25 @@ func (p *parser) isUnderlinedHeader(data []byte) int {
 	return 0
 }
 
+func (p *parser) titleBlock(out *bytes.Buffer, data []byte, doRender bool) int {
+	if data[0] != '%' {
+		return 0
+	}
+	splitData := bytes.Split(data, []byte("\n"))
+	var i int
+	for idx, b := range splitData {
+		if !bytes.HasPrefix(b, []byte("%")) {
+			i = idx // - 1
+			break
+		}
+	}
+
+	data = bytes.Join(splitData[0:i], []byte("\n"))
+	p.r.TitleBlock(out, data)
+
+	return len(data)
+}
+
 func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
 	var i, j int
 
diff --git a/block_test.go b/block_test.go
index 3c37202..c9d4a88 100644
--- a/block_test.go
+++ b/block_test.go
@@ -1045,3 +1045,19 @@ func TestFencedCodeBlock_EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK(t *testing.T) {
 	}
 	doTestsBlock(t, tests, EXTENSION_FENCED_CODE|EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK)
 }
+
+func TestTitleBlock_EXTENSION_TITLEBLOCK(t *testing.T) {
+	var tests = []string{
+		"% Some title\n" +
+			"% Another title line\n" +
+			"% Yep, more here too\n",
+		"<h1 class=\"title\">" +
+			"Some title\n" +
+			"Another title line\n" +
+			"Yep, more here too\n" +
+			"</h1>",
+	}
+
+	doTestsBlock(t, tests, EXTENSION_TITLEBLOCK)
+
+}
diff --git a/html.go b/html.go
index acf2bb7..982131c 100644
--- a/html.go
+++ b/html.go
@@ -180,6 +180,14 @@ func (options *Html) GetFlags() int {
 	return options.flags
 }
 
+func (options *Html) TitleBlock(out *bytes.Buffer, text []byte) {
+	text = bytes.TrimPrefix(text, []byte("% "))
+	text = bytes.Replace(text, []byte("\n% "), []byte("\n"), -1)
+	out.WriteString("<h1 class=\"title\">")
+	out.Write(text)
+	out.WriteString("\n</h1>")
+}
+
 func (options *Html) Header(out *bytes.Buffer, text func() bool, level int, id string) {
 	marker := out.Len()
 	doubleSpace(out)
diff --git a/latex.go b/latex.go
index 8924aca..8562746 100644
--- a/latex.go
+++ b/latex.go
@@ -55,6 +55,10 @@ func (options *Latex) BlockCode(out *bytes.Buffer, text []byte, lang string) {
 	}
 }
 
+func (options *Latex) TitleBlock(out *bytes.Buffer, text []byte) {
+
+}
+
 func (options *Latex) BlockQuote(out *bytes.Buffer, text []byte) {
 	out.WriteString("\n\\begin{quotation}\n")
 	out.Write(text)
diff --git a/markdown.go b/markdown.go
index ca67cc6..023c056 100644
--- a/markdown.go
+++ b/markdown.go
@@ -40,6 +40,7 @@ const (
 	EXTENSION_FOOTNOTES                              // Pandoc-style footnotes
 	EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK             // No need to insert an empty line to start a (code, quote, order list, unorder list)block
 	EXTENSION_HEADER_IDS                             // specify header IDs  with {#id}
+	EXTENSION_TITLEBLOCK                             // Titleblock ala pandoc
 )
 
 // These are the possible flag values for the link renderer.
@@ -145,6 +146,7 @@ type Renderer interface {
 	TableCell(out *bytes.Buffer, text []byte, flags int)
 	Footnotes(out *bytes.Buffer, text func() bool)
 	FootnoteItem(out *bytes.Buffer, name, text []byte, flags int)
+	TitleBlock(out *bytes.Buffer, text []byte)
 
 	// Span-level callbacks
 	AutoLink(out *bytes.Buffer, link []byte, kind int)