From 07abee79ed6d4c8031213a8bec743299f4892071 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Sat, 18 Jul 2020 22:33:24 -0400
Subject: [PATCH] Keep preformatting start/end lines when parsing

---
 lib/gemini.ex | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/lib/gemini.ex b/lib/gemini.ex
index f11a81e..98d4b1d 100644
--- a/lib/gemini.ex
+++ b/lib/gemini.ex
@@ -49,7 +49,9 @@ defmodule Gemini do
   @type line ::
           {:text, String.t()}
           | {:link, URI.t(), String.t() | nil}
-          | {:preformatted, String.t(), String.t() | nil}
+          | {:preformatted_start, String.t() | nil}
+          | :preformatted_end
+          | {:preformatted, String.t()}
           | {:heading, String.t(), 1 | 2 | 3}
           | {:list_item, String.t()}
           | {:quoted, String.t()}
@@ -62,19 +64,20 @@ defmodule Gemini do
     {lines, _, _} =
       doc
       |> String.split("\n")
-      |> Enum.reduce({[], false, nil}, fn line, {lines, in_preformatting, preformatting_alt} ->
+      |> Enum.reduce({[], false}, fn line, {lines, in_preformatting} ->
         preformatting_toggle = match?("```" <> _, line)
 
         cond do
           preformatting_toggle && in_preformatting ->
-            {lines, false, nil}
+            {[:preformatting_end | lines], false}
 
           preformatting_toggle && !in_preformatting ->
             "```" <> alt = line
-            {lines, true, alt}
+            alt = if length(alt) == 0, do: nil, else: alt
+            {[{:preformatting_start, alt} | lines], true}
 
           in_preformatting ->
-            {[{:preformatted, line, preformatting_alt} | lines], true, preformatting_alt}
+            {[{:preformatted, line} | lines], true}
 
           true ->
             case line do
@@ -85,25 +88,25 @@ defmodule Gemini do
                     [_, link, text] -> {link, text}
                   end
 
-                {[{:link, URI.parse(link), text} | lines], false, nil}
+                {[{:link, URI.parse(link), text} | lines], false}
 
               "###" <> rest ->
-                {[{:heading, String.trim(rest), 3} | lines], false, nil}
+                {[{:heading, String.trim(rest), 3} | lines], false}
 
               "##" <> rest ->
-                {[{:heading, String.trim(rest), 2} | lines], false, nil}
+                {[{:heading, String.trim(rest), 2} | lines], false}
 
               "#" <> rest ->
-                {[{:heading, String.trim(rest), 1} | lines], false, nil}
+                {[{:heading, String.trim(rest), 1} | lines], false}
 
               "* " <> rest ->
-                {[{:list_item, String.trim(rest)} | lines], false, nil}
+                {[{:list_item, String.trim(rest)} | lines], false}
 
               ">" <> rest ->
-                {[{:quoted, String.trim(rest)} | rest], false, nil}
+                {[{:quoted, String.trim(rest)} | rest], false}
 
               line ->
-                {[{:text, line} | lines], false, nil}
+                {[{:text, line} | lines], false}
             end
         end
       end)