From cc3a24565f4d357eb8ba83b325b8a2bfd1b8af64 Mon Sep 17 00:00:00 2001
From: Chris Hodapp <hodapp87@gmail.com>
Date: Thu, 14 Dec 2017 15:07:45 -0500
Subject: [PATCH] Enabled MathJax rendering through Pandoc

---
 blag.cabal             |  2 ++
 site.hs                | 26 ++++++++++++++++++++++----
 templates/default.html |  5 +++++
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/blag.cabal b/blag.cabal
index e4fe62e..95d68ff 100644
--- a/blag.cabal
+++ b/blag.cabal
@@ -8,5 +8,7 @@ executable site
   build-depends:    base == 4.*
                   , hakyll >= 4.6
                   , filepath
+                  , containers
+                  , pandoc
   ghc-options:      -threaded
   default-language: Haskell2010
diff --git a/site.hs b/site.hs
index daafff6..2921fc4 100644
--- a/site.hs
+++ b/site.hs
@@ -10,18 +10,36 @@ Portability : POSIX
 import           Data.Monoid (mappend)
 import           Hakyll
 import           System.FilePath
+import           Text.Pandoc.Options
 import qualified GHC.IO.Encoding as E
+import qualified Data.Set as S
 
 -- | Configuration for the RSS and ATOM feeds.
 feedConfiguration :: FeedConfiguration
 feedConfiguration = FeedConfiguration
-    { feedTitle = "hodapple blog, FIXME!"
+    { feedTitle = "hodapple blog"
     , feedDescription = "FIXME!"
     , feedAuthorName = "Chris Hodapp"
     , feedAuthorEmail = "Hodapp87@gmail.com"
     , feedRoot = "http://???"
     }
 
+-- | Alternate pandocCompiler which enables MathJax
+pandocMathCompiler :: Compiler (Item String)
+pandocMathCompiler =
+  -- Lifted straight from:
+  -- http://travis.athougies.net/posts/2013-08-13-using-math-on-your-hakyll-blog.html
+  let mathExtensions = [ Ext_tex_math_dollars
+                       , Ext_tex_math_double_backslash
+                       , Ext_latex_macros]
+      defaultExtensions = writerExtensions defaultHakyllWriterOptions
+      newExtensions = foldr S.insert defaultExtensions mathExtensions
+      writerOptions = defaultHakyllWriterOptions {
+        writerExtensions = newExtensions,
+          writerHTMLMathMethod = MathJax ""
+        }
+  in pandocCompilerWith defaultHakyllReaderOptions writerOptions
+
 -- | Main entry point for generating all code via Hakyll
 main :: IO ()
 main = do
@@ -57,7 +75,7 @@ main = do
 
     match "pages/*" $ do
         route   $ setExtension "html"
-        compile $ pandocCompiler
+        compile $ pandocMathCompiler
             >>= loadAndApplyTemplate "templates/default.html" defaultContext
             >>= relativizeUrls
 
@@ -72,7 +90,7 @@ main = do
 
     match "posts/*" $ do
         route $ setExtension "html"
-        compile $ pandocCompiler
+        compile $ pandocMathCompiler
             >>= loadAndApplyTemplate "templates/post.html"     postCtxTags
             >>= saveSnapshot "feedContent"
             >>= loadAndApplyTemplate "templates/comments.html" postCtxTags
@@ -86,7 +104,7 @@ main = do
 
     match "drafts/*" $ do
         route $ setExtension "html"
-        compile $ pandocCompiler
+        compile $ pandocMathCompiler
             >>= loadAndApplyTemplate "templates/post.html"     postCtxTags
             >>= loadAndApplyTemplate "templates/default.html"  postCtxTags
             >>= relativizeUrls
diff --git a/templates/default.html b/templates/default.html
index 653af89..043f29a 100644
--- a/templates/default.html
+++ b/templates/default.html
@@ -14,6 +14,11 @@
           -->
         <link rel="stylesheet" type="text/css" href="/css/syntax.css"/>
 
+        <!-- From http://travis.athougies.net/posts/2013-08-13-using-math-on-your-hakyll-blog.html -->
+        <script type="text/javascript"
+                src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
+        </script>
+        
         <link rel="apple-touch-icon" sizes="57x57" href="/apple-touch-icon-57x57.png">
         <link rel="apple-touch-icon" sizes="60x60" href="/apple-touch-icon-60x60.png">
         <link rel="apple-touch-icon" sizes="72x72" href="/apple-touch-icon-72x72.png">