commit 0d54357bf82869d195fedb9c1c5920e5a242b057
Author: Bùi Thành Nhân <hi@imnhan.com>
Date:   Mon Nov 2 11:25:46 2020 +0700

    fix preformatted block with alt text
    
    I really need to do proper parser tests one of these days...

diff --git a/src/mcross/document.py b/src/mcross/document.py
index 821f673..d44c698 100644
--- a/src/mcross/document.py
+++ b/src/mcross/document.py
@@ -54,7 +54,13 @@ def __repr__(self):
 
 
 class PreformattedNode(GeminiNode):
-    pass
+    __slots__ = ("alt", "text")
+    alt: str
+    text: str
+
+    def __init__(self, alt, text):
+        self.alt = alt
+        self.text = text
 
 
 def parse(text):
@@ -66,18 +72,21 @@ def parse(text):
 
     for line in text.strip().split(NEWLINE):
 
-        if line == "```":
+        if line.startswith("```"):
             if preformatted is None:
                 # start preformatted mode
-                preformatted = ""
+                preformatted = {"alt": line[3:], "text": ""}
             else:
-                nodes.append(PreformattedNode(preformatted))
+                # maybe FIXME: in case a closing ``` has trailing text, that text
+                # will be thrown away. Who cares since that would probably
+                # mean malformed gemini anyway.
+                nodes.append(PreformattedNode(**preformatted))
                 preformatted = None
 
         elif preformatted is not None:
-            if len(preformatted) > 0:
-                preformatted += "\n"
-            preformatted += line
+            if len(preformatted["text"]) > 0:
+                preformatted["text"] += "\n"
+            preformatted["text"] += line
 
         elif line.startswith("=> "):
             match = LINK_LINE_PATTERN.match(line)
diff --git a/src/mcross/gui/view.py b/src/mcross/gui/view.py
index bd0fa34..1a8ae95 100644
--- a/src/mcross/gui/view.py
+++ b/src/mcross/gui/view.py
@@ -3,16 +3,8 @@
 from tkinter import Text, Tk, font, ttk
 
 from .. import conf
-from ..document import (
-    GeminiNode,
-    H1Node,
-    H2Node,
-    H3Node,
-    LinkNode,
-    ListItemNode,
-    PreformattedNode,
-    TextNode,
-)
+from ..document import (GeminiNode, H1Node, H2Node, H3Node, LinkNode,
+                        ListItemNode, PreformattedNode, TextNode)
 from .model import Model
 from .widgets import AltButton, McEntry, ReadOnlyText
 
@@ -271,7 +263,7 @@ def render_node(node: GeminiNode, widget: Text):
         if node.name:
             widget.insert("end", f" {node.name}")
     elif nodetype is PreformattedNode:
-        widget.insert("end", f"```\n{node.text}\n```", ("pre",))
+        widget.insert("end", f"```{node.alt}\n{node.text}\n```", ("pre",))
     elif nodetype is ListItemNode:
         widget.insert("end", node.text, ("listitem",))
     elif nodetype is H1Node: