Use language name to get code coloring

In a `\code` or `~~~` or ` ``` ` environment we can define the language of a code block by specifying an extension.
In markdown we see quite often the language name as code block name (especially for `python`)
One can specify it by means of an `EXTENSION_MAPPING` but this is quite unnatural as it it not an extension.

- see to it that the extension (and thus `EXTENSION_MAPPING`) still has precedence
- in case not a known extension, try the language names.

Note: with docbook the explicit name usage was missing.

8 files changed, 69 insertions, 32 deletions

diff --git a/src/docbookvisitor.cpp b/src/docbookvisitor.cpp
index d444b7b..cde2da6 100644
--- a/src/docbookvisitor.cpp
+++ b/src/docbookvisitor.cpp
@@ -311,10 +311,15 @@ void DocbookDocVisitor::visit(DocVerbatim *s)
 {
 DB_VIS_C
   if (m_hide) return;
-  SrcLangExt langExt = getLanguageFromFileName(m_langExt);
+  QCString lang = m_langExt;
+  if (!s->language().isEmpty()) // explicit language setting
+  {
+    lang = s->language();
+  }
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch(s->type())
   {
-    case DocVerbatim::Code: // fall though
+    case DocVerbatim::Code:
       m_t << "<literallayout><computeroutput>";
       getCodeParser(m_langExt).parseCode(m_ci,s->context(),
                                          s->text(),
diff --git a/src/htmldocvisitor.cpp b/src/htmldocvisitor.cpp
index b93a2c4..fc3ca57 100644
--- a/src/htmldocvisitor.cpp
+++ b/src/htmldocvisitor.cpp
@@ -517,7 +517,7 @@ void HtmlDocVisitor::visit(DocVerbatim *s)
   {
     lang = s->language();
   }
-  SrcLangExt langExt = getLanguageFromFileName(lang);
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch(s->type())
   {
     case DocVerbatim::Code:
diff --git a/src/latexdocvisitor.cpp b/src/latexdocvisitor.cpp
index e6c9363..f736498 100644
--- a/src/latexdocvisitor.cpp
+++ b/src/latexdocvisitor.cpp
@@ -346,7 +346,7 @@ void LatexDocVisitor::visit(DocVerbatim *s)
   {
     lang = s->language();
   }
-  SrcLangExt langExt = getLanguageFromFileName(lang);
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch(s->type())
   {
     case DocVerbatim::Code:
diff --git a/src/mandocvisitor.cpp b/src/mandocvisitor.cpp
index 875cd14..95d15f8 100644
--- a/src/mandocvisitor.cpp
+++ b/src/mandocvisitor.cpp
@@ -195,10 +195,10 @@ void ManDocVisitor::visit(DocVerbatim *s)
   {
     lang = s->language();
   }
-  SrcLangExt langExt = getLanguageFromFileName(lang);
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch (s->type())
   {
-    case DocVerbatim::Code: // fall though
+    case DocVerbatim::Code:
       if (!m_firstCol) m_t << endl;
       m_t << ".PP" << endl;
       m_t << ".nf" << endl;
diff --git a/src/rtfdocvisitor.cpp b/src/rtfdocvisitor.cpp
index 2bd2c29..08d5b63 100644
--- a/src/rtfdocvisitor.cpp
+++ b/src/rtfdocvisitor.cpp
@@ -299,10 +299,10 @@ void RTFDocVisitor::visit(DocVerbatim *s)
   {
     lang = s->language();
   }
-  SrcLangExt langExt = getLanguageFromFileName(lang);
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch(s->type())
   {
-    case DocVerbatim::Code: // fall though
+    case DocVerbatim::Code:
       m_t << "{" << endl;
       m_t << "\\par" << endl;
       m_t << rtf_Style_Reset << getStyle("CodeExample");
diff --git a/src/util.cpp b/src/util.cpp
index 3feb8db..e4c32c3 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -5539,29 +5539,30 @@ static struct Lang2ExtMap
   const char *langName;
   const char *parserName;
   SrcLangExt parserId;
+  const char *defExt;
 }
 g_lang2extMap[] =
 {
 //  language       parser           parser option
-  { "idl",         "c",             SrcLangExt_IDL      },
-  { "java",        "c",             SrcLangExt_Java     },
-  { "javascript",  "c",             SrcLangExt_JS       },
-  { "csharp",      "c",             SrcLangExt_CSharp   },
-  { "d",           "c",             SrcLangExt_D        },
-  { "php",         "c",             SrcLangExt_PHP      },
-  { "objective-c", "c",             SrcLangExt_ObjC     },
-  { "c",           "c",             SrcLangExt_Cpp      },
-  { "c++",         "c",             SrcLangExt_Cpp      },
-  { "slice",       "c",             SrcLangExt_Slice    },
-  { "python",      "python",        SrcLangExt_Python   },
-  { "fortran",     "fortran",       SrcLangExt_Fortran  },
-  { "fortranfree", "fortranfree",   SrcLangExt_Fortran  },
-  { "fortranfixed", "fortranfixed", SrcLangExt_Fortran  },
-  { "vhdl",        "vhdl",          SrcLangExt_VHDL     },
-  { "xml",         "xml",           SrcLangExt_XML      },
-  { "sql",         "sql",           SrcLangExt_SQL      },
-  { "md",          "md",            SrcLangExt_Markdown },
-  { 0,             0,              (SrcLangExt)0        }
+  { "idl",         "c",             SrcLangExt_IDL,      ".idl" },
+  { "java",        "c",             SrcLangExt_Java,     ".java"},
+  { "javascript",  "c",             SrcLangExt_JS,       ".js"  },
+  { "csharp",      "c",             SrcLangExt_CSharp,   ".cs"  },
+  { "d",           "c",             SrcLangExt_D,        ".d"   },
+  { "php",         "c",             SrcLangExt_PHP,      ".php" },
+  { "objective-c", "c",             SrcLangExt_ObjC,     ".m"   },
+  { "c",           "c",             SrcLangExt_Cpp,      ".c"   },
+  { "c++",         "c",             SrcLangExt_Cpp,      ".cpp" },
+  { "slice",       "c",             SrcLangExt_Slice,    ".ice" },
+  { "python",      "python",        SrcLangExt_Python,   ".py"  },
+  { "fortran",     "fortran",       SrcLangExt_Fortran,  ".f"   },
+  { "fortranfree", "fortranfree",   SrcLangExt_Fortran,  ".f90" },
+  { "fortranfixed", "fortranfixed", SrcLangExt_Fortran,  ".f"   },
+  { "vhdl",        "vhdl",          SrcLangExt_VHDL,     ".vhdl"},
+  { "xml",         "xml",           SrcLangExt_XML,      ".xml" },
+  { "sql",         "sql",           SrcLangExt_SQL,      ".sql" },
+  { "md",          "md",            SrcLangExt_Markdown, ".md"  },
+  { 0,             0,              (SrcLangExt)0,        0      }
 };
 
 bool updateLanguageMapping(const QCString &extension,const QCString &language)
@@ -5666,7 +5667,7 @@ void addCodeOnlyMappings()
   updateLanguageMapping(".sql",   "sql");
 }
 
-SrcLangExt getLanguageFromFileName(const QCString& fileName)
+SrcLangExt getLanguageFromFileName(const QCString& fileName, SrcLangExt defLang)
 {
   QFileInfo fi(fileName);
   // we need only the part after the last ".", newer implementations of QFileInfo have 'suffix()' for this.
@@ -5680,7 +5681,37 @@ SrcLangExt getLanguageFromFileName(const QCString& fileName)
       return (SrcLangExt)*pVal;
     }
   //printf("getLanguageFromFileName(%s) not found!\n",fileName.data());
-  return SrcLangExt_Cpp; // not listed => assume C-ish language.
+  return defLang; // not listed => assume default specified language
+}
+
+/// Routine to handle the language attribute of the `\code` command
+SrcLangExt getLanguageFromCodeLang(QCString &fileName)
+{
+  // try the extension
+  SrcLangExt lang = getLanguageFromFileName(fileName, SrcLangExt_Unknown);
+  if (lang == SrcLangExt_Unknown)
+  {
+    // try the language names
+    const Lang2ExtMap *p = g_lang2extMap;
+    QCString langName = fileName.lower();
+    if (langName.at(0)=='.') langName = langName.mid(1);
+    while (p->langName)
+    {
+      if (langName==p->langName)
+      {
+        // found the language
+        lang     = p->parserId;
+        fileName = p->defExt;
+        break;
+      }
+      p++;
+    }
+    if (!p->langName)
+    {
+      return SrcLangExt_Cpp;
+    }
+  }
+  return lang;
 }
 
 QCString getFileNameExtension(QCString fn)
diff --git a/src/util.h b/src/util.h
index 6d50d88..946b9f6 100644
--- a/src/util.h
+++ b/src/util.h
@@ -362,7 +362,8 @@ bool findAndRemoveWord(QCString &s,const QCString &word);
 QCString stripLeadingAndTrailingEmptyLines(const QCString &s,int &docLine);
 
 bool updateLanguageMapping(const QCString &extension,const QCString &parser);
-SrcLangExt getLanguageFromFileName(const QCString& fileName);
+SrcLangExt getLanguageFromFileName(const QCString& fileName, SrcLangExt defLang=SrcLangExt_Cpp);
+SrcLangExt getLanguageFromCodeLang(QCString &fileName);
 QCString getFileNameExtension(QCString fn);
 void initDefaultExtensionMapping();
 void addCodeOnlyMappings();
diff --git a/src/xmldocvisitor.cpp b/src/xmldocvisitor.cpp
index 29990c9..3178328 100644
--- a/src/xmldocvisitor.cpp
+++ b/src/xmldocvisitor.cpp
@@ -247,10 +247,10 @@ void XmlDocVisitor::visit(DocVerbatim *s)
   {
     lang = s->language();
   }
-  SrcLangExt langExt = getLanguageFromFileName(lang);
+  SrcLangExt langExt = getLanguageFromCodeLang(lang);
   switch(s->type())
   {
-    case DocVerbatim::Code: // fall though
+    case DocVerbatim::Code:
       m_t << "<programlisting";
       if (!s->language().isEmpty())
           m_t << " filename=\"" << lang << "\">";