Merge pull request #85 from kisaragi-hiu/hl_lines

highlightCodeBlock: expose params so they can be passed to Chroma by users

blorg/util.go

@@ -55,7 +55,7 @@ func getWriter() org.Writer {
 	return w
 }
 
-func highlightCodeBlock(source, lang string, inline bool) string {
+func highlightCodeBlock(source, lang string, inline bool, params map[string]string) string {
 	var w strings.Builder
 	l := lexers.Get(lang)
 	if l == nil {
@@ -63,7 +63,14 @@ func highlightCodeBlock(source, lang string, inline bool) string {
 	}
 	l = chroma.Coalesce(l)
 	it, _ := l.Tokenise(nil, source)
-	_ = html.New().Format(&w, styles.Get("github"), it)
+	options := []html.Option{}
+	if params[":hl_lines"] != "" {
+		ranges := org.ParseRanges(params[":hl_lines"])
+		if ranges != nil {
+			options = append(options, html.HighlightLines(ranges))
+		}
+	}
+	_ = html.New(options...).Format(&w, styles.Get("github"), it)
 	if inline {
 		return `<div class="highlight-inline">` + "\n" + w.String() + "\n" + `</div>`
 	}

main.go

@@ -119,7 +119,7 @@ func render(args []string) {
 	}
 }
 
-func highlightCodeBlock(source, lang string, inline bool) string {
+func highlightCodeBlock(source, lang string, inline bool, params map[string]string) string {
 	var w strings.Builder
 	l := lexers.Get(lang)
 	if l == nil {
@@ -127,7 +127,14 @@ func highlightCodeBlock(source, lang string, inline bool) string {
 	}
 	l = chroma.Coalesce(l)
 	it, _ := l.Tokenise(nil, source)
-	_ = html.New().Format(&w, styles.Get("friendly"), it)
+	options := []html.Option{}
+	if params[":hl_lines"] != "" {
+		ranges := org.ParseRanges(params[":hl_lines"])
+		if ranges != nil {
+			options = append(options, html.HighlightLines(ranges))
+		}
+	}
+	_ = html.New(options...).Format(&w, styles.Get("friendly"), it)
 	if inline {
 		return `<div class="highlight-inline">` + "\n" + w.String() + "\n" + `</div>`
 	}

org/html_writer.go

@@ -19,7 +19,7 @@ import (
 // HTMLWriter exports an org document into a html document.
 type HTMLWriter struct {
 	ExtendingWriter     Writer
-	HighlightCodeBlock  func(source, lang string, inline bool) string
+	HighlightCodeBlock  func(source, lang string, inline bool, params map[string]string) string
 	PrettyRelativeLinks bool
 
 	strings.Builder
@@ -66,7 +66,7 @@ func NewHTMLWriter() *HTMLWriter {
 		document:   &Document{Configuration: defaultConfig},
 		log:        defaultConfig.Log,
 		htmlEscape: true,
-		HighlightCodeBlock: func(source, lang string, inline bool) string {
+		HighlightCodeBlock: func(source, lang string, inline bool, params map[string]string) string {
 			if inline {
 				return fmt.Sprintf("<div class=\"highlight-inline\">\n<pre>\n%s\n</pre>\n</div>", html.EscapeString(source))
 			}
@@ -129,7 +129,7 @@ func (w *HTMLWriter) WriteBlock(b Block) {
 		if len(b.Parameters) >= 1 {
 			lang = strings.ToLower(b.Parameters[0])
 		}
-		content = w.HighlightCodeBlock(content, lang, false)
+		content = w.HighlightCodeBlock(content, lang, false, params)
 		w.WriteString(fmt.Sprintf("<div class=\"src src-%s\">\n%s\n</div>\n", lang, content))
 	case "EXAMPLE":
 		w.WriteString(`<pre class="example">` + "\n" + html.EscapeString(content) + "\n</pre>\n")
@@ -159,7 +159,7 @@ func (w *HTMLWriter) WriteInlineBlock(b InlineBlock) {
 	switch b.Name {
 	case "src":
 		lang := strings.ToLower(b.Parameters[0])
-		content = w.HighlightCodeBlock(content, lang, true)
+		content = w.HighlightCodeBlock(content, lang, true, nil)
 		w.WriteString(fmt.Sprintf("<div class=\"src src-inline src-%s\">\n%s\n</div>", lang, content))
 	case "export":
 		if strings.ToLower(b.Parameters[0]) == "html" {

org/testdata/hl-lines.html

@@ -0,0 +1,12 @@
+<p>Lines in a source block can be highlighted with <code class="verbatim">:hl_lines</code>.</p>
+<div class="src src-emacs-lisp">
+<div class="highlight">
+<pre>
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+</pre>
+</div>
+</div>

org/testdata/hl-lines.org

@@ -0,0 +1,9 @@
+Lines in a source block can be highlighted with =:hl_lines=.
+
+#+begin_src emacs-lisp :hl_lines 3-4
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+#+end_src

org/testdata/hl-lines.pretty_org

@@ -0,0 +1,9 @@
+Lines in a source block can be highlighted with =:hl_lines=.
+
+#+BEGIN_SRC emacs-lisp :hl_lines 3-4
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+(+ 1 2)
+#+END_SRC

org/util.go

@@ -1,5 +1,10 @@
 package org
 
+import (
+	"strconv"
+	"strings"
+)
+
 func isSecondBlankLine(d *Document, i int) bool {
 	if i-1 <= 0 {
 		return false
@@ -17,3 +22,49 @@ func isImageOrVideoLink(n Node) bool {
 	}
 	return false
 }
+
+// Parse ranges like this:
+// "3-5" -> [[3, 5]]
+// "3 8-10" -> [[3, 3], [8, 10]]
+// "3  5 6" -> [[3, 3], [5, 5], [6, 6]]
+//
+// This is Hugo's hlLinesToRanges with "startLine" removed and errors
+// ignored.
+func ParseRanges(s string) [][2]int {
+	var ranges [][2]int
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return ranges
+	}
+	fields := strings.Split(s, " ")
+	for _, field := range fields {
+		field = strings.TrimSpace(field)
+		if field == "" {
+			continue
+		}
+		numbers := strings.Split(field, "-")
+		var r [2]int
+		if len(numbers) > 1 {
+			first, err := strconv.Atoi(numbers[0])
+			if err != nil {
+				return ranges
+			}
+			second, err := strconv.Atoi(numbers[1])
+			if err != nil {
+				return ranges
+			}
+			r[0] = first
+			r[1] = second
+		} else {
+			first, err := strconv.Atoi(numbers[0])
+			if err != nil {
+				return ranges
+			}
+			r[0] = first
+			r[1] = first
+		}
+
+		ranges = append(ranges, r)
+	}
+	return ranges
+}

org/util_test.go

@@ -0,0 +1,38 @@
+package org
+
+import (
+	"fmt"
+	"testing"
+)
+
+var parseRangesTests = map[string][][2]int{
+	"3-5":           {{3, 5}},
+	"3 8-10":        {{3, 3}, {8, 10}},
+	"3   5 6":       {{3, 3}, {5, 5}, {6, 6}},
+	" 9-10 5-6  3 ": {{9, 10}, {5, 6}, {3, 3}},
+}
+
+func TestParseRanges(t *testing.T) {
+	for s, expected := range parseRangesTests {
+		t.Run(s, func(t *testing.T) {
+			actual := ParseRanges(s)
+			// If this fails it looks like:
+			// util_test.go:<line>:  9-10 5-6  3 :
+			//     --- Actual
+			//     +++ Expected
+			//     @@ -1 +1 @@
+			//     -[[9 10] [5 9] [3 3]]
+			//     +[[9 10] [5 6] [3 3]]
+			if len(actual) != len(expected) {
+				t.Errorf("%v:\n%v", s, diff(fmt.Sprintf("%v", actual), fmt.Sprintf("%v", expected)))
+			} else {
+				for i := range actual {
+					if actual[i] != expected[i] {
+						t.Errorf("%v:\n%v", s, diff(fmt.Sprintf("%v", actual), fmt.Sprintf("%v", expected)))
+					}
+				}
+			}
+		})
+	}
+
+}