Merge pull request #39 from albert-github/feature/doc_debug

Finally the data for members of classes, namespaces, and files is stored in

the subclass MemberDef.

Producing debug output

----------------------

Within doxygen there are a number of ways to obtain debug output. Besides the

invasive method of  putting print statements in the code there are a number of

easy ways to get debug information.

- Compilation of `.l` files<br>

  This is also an invasive method but it will be automatically done by the

  `flex / lex` command. The result is that of each input line the (lex) rule(s)

  that are applied on it are shown.

  - windows

    - in the Visual C++ GUI

      - find the required `.l` file

      - select the `Properties` of this file

      - set the item `Write used lex rules` to `Yes`

      - see to it that the `.l` file is newer than the corresponding `.cpp` file

        or remove the corresponding `.cpp` file

  - unices

    - global change<br>

      In the chapter "Doxygen's internals" a `perl` script is given to toggle the

      possibility of having the rules debug information.

    - command line change<br>

      It is possible to the option `LEX="flex -d"` with the `make` command on the

      command line. In this case the `.l` that are converted to the corresponding

      `.cpp` files during this `make` get the rules debug information.<br>

      To undo the rules debug information output just recompile the file with

      just `make`.<br>

      Note this method applies for all the `.l` files that are rebuild to `.cpp`

      files so be sure that only the `.l` files(s) of which you want to have the

      rules debug information is (are) newer than the corresponding `.cpp`

      file(s).

- Running doxygen<br>

  During a run of doxygen it is possible to specify the `-d` option with the

  following possibilities (each option has to be preceded by `-d`):

  - findmembers<br>

    Gives of global, class, module members its scope, arguments and other relevant information.

  - functions<br>

    Gives of functions its scope, arguments and other relevant information.

  - variables<br>

    Gives of variables its scope and other relevant information.

  - classes<br>

    Gives of classes en modules its scope and other relevant information.

  - preprocessor<br>

    Shows the results of the preprocessing phase, i.e. results from include files, 

    <tt>\#define</tt> statements etc., definitions in the doxygen configuration file like:

    `EXPAND_ONLY_PREDEF`, `PREDEFINED` and `MACRO_EXPANSION`. 

  - commentcnv<br>

    Shows the results of the comment conversion, the comment conversion does the

    following:

     - It converts multi-line C++ style comment blocks (that are aligned)

       to C style comment blocks (if `MULTILINE_CPP_IS_BRIEF` is set to `NO`).

     - It replaces aliases with their definition (see `ALIASES`)

     - It handles conditional sections (<tt>\\cond ... \\endcond</tt> blocks)

  - commentscan<br>

    Will print each comment block before and after the comment is interpreted by

    the comment scanner.

  - printtree<br>

    Give the results in in pretty print way, i.e. in an XML like way with each

    level indented by a `"."` (dot).

  - time<br>

    Provides information of the different stages of the doxygen process.

  - extcmd<br>

    Shows which external commands are executed and which pipes are opened.

  - markdown<br>

    Will print each comment block before and after Markdown processing.

  - filteroutput<br>

    Gives the output of the output as result of the filter command (when a filter

    command is specified)

  - validate<br>

    Currently not used

Producing output

----------------

  - comment conversion

  - comment scanner

  - markdown processor

  - doc tokeninzer

  - doc tokenizer

  - doc parser

  - doc visitors

- Diagrams and Images