enable Highlight.js line numbers and -highlights

exampleSite/config.toml

@@ -20,8 +20,12 @@ name = "Josh Dzielak"
 [markup.goldmark.renderer]
 unsafe = true
 [markup.highlight]
+# setting the theme for highlighting by Hugo 
 # we need a style that looks good in both light and dark background!
 style = "tango"
+# to allow the use of Highlight.js line numbers and highlights
+# (see https://github.com/hakimel/reveal.js#line-numbers--highlights)
+codeFences = false
 
 [outputFormats.Reveal]
 baseName = "index"
@@ -30,6 +34,8 @@ isHTML = true
 
 [params.reveal_hugo]
 history = true
+# setting the theme for highlighting by Highlight.js
+highlight_theme = "github"
 
 # used in content/template-example
 [params.reveal_hugo.templates.grey]

layouts/partials/reveal-hugo/slides.html

@@ -7,6 +7,10 @@
     <!-- <code> blocks processed by Hugo's highlighter have a data-lang attribute. For those, we disable -->
     <!-- highlight.js by changing the language class to "nohighlight", and adding "data-noescape".       -->
     {{- $content := replaceRE `<code class="language-\w+"\s+data-lang="\w+"` `<code class="nohighlight" data-noescape` $content -}}    
+    <!-- enable Highlight.js line numbers when the markdown code block language selection is followed by "{}" e.g. ```js{} -->
+    {{- $content := replaceRE `(<code class="language-\w+){}(">)` `$1" data-line-numbers>` $content -}}
+    <!-- enable Highlight.js line highlights when the language selection is followed by "{<line numbers>}" e.g. ```js{1,5-7} -->          
+    {{- $content := replaceRE `(<code class="language-\w+){(\S+)}(">)` `$1" data-line-numbers="$2">` $content -}}            
     <!-- Support both <hr /> (blackfriday) and <hr> (mmark) -->
     {{- $content := replace $content "<hr>" "<hr />" -}}
     <!-- Split the processed content by <hr /> tag -->