Merge pull request #210 from albert-github/feature/snippet_from_current_file

Create an easy possibility to take a snippet from the current file.

doc/commands.doc

@@ -2147,7 +2147,8 @@ Commands for displaying examples
  \addindex \\snippet
  Where the \ref cmdinclude "\\include" command can be used to include
  a complete file as source code, this command can be used to quote only
- a fragment of a source file.
+ a fragment of a source file. In case `this` is used as <file-name> the
+ current file is taken as file to take the snippet from.
 
  For example, the putting the following command in the documentation,
  references a snippet in file \c example.cpp residing in a subdirectory 

src/docparser.cpp

@@ -5217,6 +5217,7 @@ void DocPara::handleInclude(const QCString &cmdName,DocInclude::Type t)
   QCString blockId;
   if (t==DocInclude::Snippet)
   {
+    if (fileName == "this") fileName=g_fileName;
     doctokenizerYYsetStateSnippet();
     tok=doctokenizerYYlex();
     doctokenizerYYsetStatePara();