QTextMarkdownWriter: write fenced code blocks with language declaration

MD4C now makes it possible to detect indented and fenced code blocks:
https://github.com/mity/md4c/issues/81
Fenced code blocks have the advantages of being easier to write by hand,
and having an "info string" following the opening fence, which is commonly
used to declare the language.

Also, the HTML parser now recognizes tags of the form
<pre class="language-foo">
which is one convention for declaring the programming language
(as opposed to human language, for which the lang attribute would be used):
https://stackoverflow.com/questions/5134242/semantics-standards-and-using-the-lang-attribute-for-source-code-in-markup
So it's possible to read HTML and write markdown without losing this information.

It's also possible to read markdown with any type of code block:
fenced with ``` or ~~~, or indented, and rewrite it the same way.

Change-Id: I33c2bf7d7b66c8f3ba5bdd41ab32572f09349c47
Reviewed-by: Gatis Paeglis <gatis.paeglis@qt.io>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1 files changed, 6 insertions, 2 deletions

diff --git a/src/gui/text/qtextmarkdownimporter.cpp b/src/gui/text/qtextmarkdownimporter.cpp
index 223eb01e55..8a9bb3953c 100644
--- a/src/gui/text/qtextmarkdownimporter.cpp
+++ b/src/gui/text/qtextmarkdownimporter.cpp
@@ -165,12 +165,13 @@ int QTextMarkdownImporter::cbEnterBlock(int blockType, void *det)
         MD_BLOCK_CODE_DETAIL *detail = static_cast<MD_BLOCK_CODE_DETAIL *>(det);
         m_codeBlock = true;
         m_blockCodeLanguage = QLatin1String(detail->lang.text, int(detail->lang.size));
+        m_blockCodeFence = detail->fence_char;
         QString info = QLatin1String(detail->info.text, int(detail->info.size));
         m_needsInsertBlock = true;
         if (m_blockQuoteDepth)
-            qCDebug(lcMD, "CODE lang '%s' info '%s' inside QUOTE %d", qPrintable(m_blockCodeLanguage), qPrintable(info), m_blockQuoteDepth);
+            qCDebug(lcMD, "CODE lang '%s' info '%s' fenced with '%c' inside QUOTE %d", qPrintable(m_blockCodeLanguage), qPrintable(info), m_blockCodeFence, m_blockQuoteDepth);
         else
-            qCDebug(lcMD, "CODE lang '%s' info '%s'", qPrintable(m_blockCodeLanguage), qPrintable(info));
+            qCDebug(lcMD, "CODE lang '%s' info '%s' fenced with '%c'", qPrintable(m_blockCodeLanguage), qPrintable(info), m_blockCodeFence);
     } break;
     case MD_BLOCK_H: {
         MD_BLOCK_H_DETAIL *detail = static_cast<MD_BLOCK_H_DETAIL *>(det);
@@ -326,6 +327,7 @@ int QTextMarkdownImporter::cbLeaveBlock(int blockType, void *detail)
     case MD_BLOCK_CODE: {
         m_codeBlock = false;
         m_blockCodeLanguage.clear();
+        m_blockCodeFence = 0;
         if (m_blockQuoteDepth)
             qCDebug(lcMD, "CODE ended inside QUOTE %d", m_blockQuoteDepth);
         else
@@ -540,6 +542,8 @@ void QTextMarkdownImporter::insertBlock()
     }
     if (m_codeBlock) {
         blockFormat.setProperty(QTextFormat::BlockCodeLanguage, m_blockCodeLanguage);
+        if (m_blockCodeFence)
+            blockFormat.setProperty(QTextFormat::BlockCodeFence, QString(QLatin1Char(m_blockCodeFence)));
         charFormat.setFont(m_monoFont);
     } else {
         blockFormat.setTopMargin(m_paragraphMargin);