path: root/docs/HACKING.txt

----------------------------
Mana Hacking Guide
----------------------------

This guide is also available at http://gitorious.org/mana/pages/Hacking
including more tips about C++ programming in general.

With multiple coders working on the same source files, there needs to be a
standard specifying how code is written down. Not doing so can cause quite some
annoyance for certain coders and easily creates more version conflicts than
necessary.

* Indentation:
  Code is indented using 4 spaces, no tabs.

* Line length:
  Should not exceed 79 characters.

  One reason for this is to keep code readable. In such cases it would often be
  better to spread the line over multiple lines or use some extra temporary
  variables. Another reason is that some of us are using editors that default
  to an 80 character wide screen, and often put two instances next to
  eachother. 79 character wide lines leave just a spot for the cursor at the
  end of the line.

* Control constructs like this:

  Good:

  if (condition)
  {
  }
  else
  {
  }

  for (init; condition; step)
  {
  }

  while (condition)
  {
  }

  /**
   * Documentation about behaviour
   * ...
   *
   * @param param1 the first argument
   * @param param2 the second argument
   */
  void function(param1, param2)
  {
  }

  class TheClass : public TheSubclass
  {
  };

  When there is only one statement you may leave out the braces, but don't
  place the statement on the same line as the condition:

  Good:

  if (condition)
      statement;

  Bad:

  if (condition) statement;

* Includes:
  Source files should include their header first, to make sure the headers are
  self-contained. After that follow other project includes, grouped by
  directory and alphabetically ordered. System includes come last. All project
  includes are done relative from the 'src' directory.

  Good (subdirectory/source.cpp):

  #include "subdirectory/header.h"

  #include "somesub/bar.h"
  #include "somesub/zaro.h"

  #include <systemlib.h>

* Comments:
  Single line C++ style comments are indented the same as the previous line.

  Good:
  // comment

  Multiple line C style comments are initially indented like previous line
  except every new line of the comment begins with a asterisk ('*') which lines
  up with the initial asterisk of the comment opening (1 space indent). The
  comment is closed also with the asterisk lining up. Comment text is only
  placed on a line starting with a asterisk.

  Good:
  /*
   * Some comment
   * additional comment material
   */

  Bad:
  /* text
  comment
  */

  Note that for documenting functions, methods and other things that can use
  documentation, you should use Doxygen style as in the function example above.
  For details see the manual at http://www.doxygen.org/.

* Whitespace examples:

  Good:
  x = ((5 + 4) * 3) / 1.5;
  afunction(12, 3, (1 + 1));

  Bad:
  x = ( ( 5 + 4 ) * 3 ) / 1.5;
  afunction(12,3,(1+1));

* Method, class, member and constant naming is based on the
  generally accepted way Java code is written.

  Class:            CapitalizedWords
  Method:           camelCase
  Member:           mCamelCase
  Constant/enum:    UPPERCASE_UNDERSCORES

  To denote global variables and functions the lowercase_underscores style may
  be used. Hungarian style should be avoided.

* Whenever you add a new source file somewhere in ./src do not forget to add
  them in ./src/Makefile.am as well!