.. -*- coding: utf-8 -*-












.. role:: sref(numref)
.. role:: xref(numref)
.. Copyright (C) 2019, Wolfgang Scherer, <Wolfgang.Scherer at gmx.de>

.. This file is part of Development.

.. Permission is granted to copy, distribute and/or modify this document
.. under the terms of the GNU Free Documentation License, Version 1.3
.. or any later version published by the Free Software Foundation;
.. with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
.. A copy of the license is included in the section entitled "GNU
.. Free Documentation License".

.. inline comments (with du_comment_role)
.. role:: rem(comment)
.. role:: html(raw)
   :format: html
.. role:: shx(code)
   :language: sh

.. >>CODD Introduction

==================================================
:rem:`|||:sec:|||`\ Introduction
==================================================

Software development is as old as human history, it has given us many
a religious belief system, used to control human brains, ultimately
eliciting desired behavior in the attached human body.

.. >>CODD Chapter

==================================================
:rem:`|||:sec:|||`\ Software development model
==================================================

.. uml::

   @startuml

   state "Design" as D
   state "Design Review" as RD
   state "Implementation" as I
   state "Implementation Review" as RI
   state "Refactoring Review" as RR

   [*] --> D

   D --> RD : finished
   RD --> D : rejected
   RD --> I : approved
   I -->  RR: problem
   RR --> D : re-design
   RR --> I : documentation only\n"known bug"

   I -->  RI: finished
   RI --> RR : rejected
   RI --> [*] : approved

   @enduml

==================================================
:rem:`|||:sec:|||`\ Control Structures
==================================================

All control structures can be reduced to a conditional jump (see
`Control Structures`_ (German)).

The unconditional while loop (endless loop) with a break before the
repetition can be used to simulate complex free form `case / when`_
structures that do not fit the if / elseif cascade nicely.

With a conventional while loop, initialization/continuation code:is
somethimes duplicated (see :xref:`lst:duplicated initcont code`).

.. _`lst:duplicated initcont code`:
.. code-block:: python
   :caption: duplicated init/cont code
   :linenos:

   ch = get_char()
   while ch != EOF:
       print(ch)
       ch = get_char()

:xref:`lst:single instance of initcont code` shows, how this
duplication can be avoided.

.. _`lst:single instance of initcont code`:
.. code-block:: python
   :caption: single instance of init/cont code
   :linenos:

   while True:
       ch = get_char()
       if ch == EOF:
          break
       print(ch)

Another common problem is found in shell scripts, when it is necessary
to determine whether one or more files actually exist (see
:xref:`lst:file existence check`).

.. _`lst:file existence check`:
.. code-block:: sh
   :caption: file existence check
   :linenos:

   # clear first_readable                                             #a0 :;
   first_readable=
   # while (for each _file in screenlog.?) is (do)                    #a0
   for _file in screenlog.?;
   do
       # if (_file is **not** readable?) then (yes)                   #a0
       test -r "${_file}" ||
           break                                                      #a0
       # endif                                                        #a0
       # set first_readable = "${_file}"                              #a0 :;;
       first_readable="${_file}"
       break                                                          #a0
   done                                                               #a0
   # if (first_readable is empty?) then (yes)                         #a0
   test -z "${first_readable}" && ...
   # endif                                                            #a0

:xref:`fig:activitiy diagram for file existence check` shows the logic
behind the file existence check.

.. _`fig:activitiy diagram for file existence check`:
.. uml::
   :caption: activitiy diagram for file existence check

   @startuml /' a0 '/
   skinparam padding 1
   start
     :clear first_readable;
      while (for each _file in screenlog.?) is (do)
          if (_file is **not** readable?) then (yes)
              break
          endif
          :set first_readable = "${_file}";
          break
      endwhile
      if (first_readable is empty?) then (yes)
      endif
   stop
   @enduml

.. _`Control Structures`: http://sw-amt.ws/~kurs/basics/control-structures/html/ctrl-struct_tf.html
.. _`Case / When`: http://sw-amt.ws/~kurs/basics/control-structures/html/node19.html

.. >>CODD Conclusion
.. >>CODD Appendix A

.. \|:here:|

.. >>CODD Notes
.. ==================================================
.. :rem:`|||:sec:|||`\ Footnotes
.. ==================================================

:html:`<hr>`

.. \[#]

.. \|:info:| put local references here
.. \|:info:| put local definitions here
.. include:: doc_defs.inc
.. include:: abbrev_defs.inc
.. include:: doc_defs_combined.inc
..
  .. \||<-snap->|| doc_standalone
  .. include:: doc/doc_defs_secret.inc
  .. \||<-snap->|| doc_standalone
  .. \||<-snap->|| not_doc_standalone
  .. include:: doc_defs_secret.inc
  .. \||<-snap->|| not_doc_standalone

.. _`Wolfgang Scherer`: wolfgang.scherer@gmx.de