spot/HACKING

Bootstraping from CVS:
======================

Some files in SPOT's source tree are generated.  They are distributed
so that users do not need to tools to rebuild them, but we don't keep
all of them under CVS because it can generate lots of changes or
conflicts.

Here are the tools you need to bootstrap the CVS tree, or more
generally if you plan to regenerate some of the generated files.

  GNU Autoconf >= 2.59
  GNU Automake >= 1.8
  GNU Libtool >= 1.4
  GNU Flex (the version probably doesn't matter much, we used 2.5.31)
  The CVS version of GNU Bison (called 1.875c at the time of writing)
  SWIG 1.3.21
  Doxygen >= 1.3.5

Bootstrap the CVS tree by running

  autoreconf -vfi

and then go on with the usual

  ./configure
  make


Coding conventions:
===================

Here are the conventions we follow in Spot, so that the code looks
homogeneous.  Please follow these strictly.  Since this is free
software, uniformity of the code matters a lot.  Most of these
conventions are derived from the GNU Coding Standards
(http://www.gnu.org/prep/standards.html) with the notable exception
that we do not put a space before the opening parenthesis in function
calls (this is hardly readable when chaining method calls).

Comments
--------

  * The language to use is American.

  * When comments are sentences, they should start with a capital and
    end with a dot.  Dots that end sentences should be followed by two
    spaces (i.e., American typing convention), like in this paragraph.

  * Prefer C++-style comments (// foo) to C-style comments (/* foo */).
    Use /// for Doxygen comments.

Formating
---------

  * Braces are always on their own line.

  * Text within braces is two-space indented.

    {
      f(12);

    }

  * Anything after a control statement is two-space indented.  This
    includes braces.

    if (test)
      {
        f(123);
	while (test2)
	  g(456);
      }

  * Braces from function/structure/enum/class/namespace definitions
    are not indented.

    class foo
    {
    public:
      Foo();
    protected:
      static int get_mumble();
    };

  * The above corresponds to the `gnu' indentation style under Emacs.

  * Put return types and linkage specifiers on their own line in
    function/method _definitions_:

    static int
    Foo::get_mumble()
    {
      return 2;
    }

    This makes it easier to grep functions in the code.

    Function/method declaration are usually written on one line:

    int get_bar(int i);

  * Put a space before the opening parenthesis in control statements

    if (test)
      {
        do
	  {
	    something();
	  }
	while (0);
      }

  * No space before parentheses in function calls.
    (`some()->foo()->bar()' is far more readable than
    `some ()->foo ()->bar ()' is)

  * No space after opening or before closing parentheses, however
    put a space after commas (as in english).

    func(arg1, arg2, arg3);

  * No useless parentheses in return statements.

    return 2;    (not `return (2);')

  * Spaces around infix binary or ternary operators:

    2 + 2;
    a = b;
    a <<= (3 + 5) * 3 + f(67 + (really ? 45 : 0));

  * No space after prefix unary operators, or before postfix unary
    operators:

    if (!test && y++ != 0)
      {
        ++x;
      }

  * When an expression spans over several lines, split it before
    operators.  If it's inside a parenthesis, the following lines
    should be 1-indented w.r.t. the opening parenthesis.

    if (foo_this_is_long && bar > win(x, y, z)
        && !remaining_condition)
      {
        ...
      }

  * `else if' can be put as-is on a single line.

  * No line should be larger than 80 columns.
    If a line takes more than 80 columns, split it or rethink it.

  * Labels or case statements are back-indented by two spaces,
    without space before the `:'.

    if (something)
      {
      top:
        bar = foo();
        switch (something_else)
	  {
	  case first_case:
	    f();
	    break;
	  case second_case:
	    g();
	    break;
	  default:
	    goto top;
	  }
      }

  * Pointers and references are part of the type, and should be put
    near the type, not near the variable.

      int* p;        // not `int *p;'
      list& l;       // not `list &l;'
      void* magic(); // not `void *magic();'

  * Do not declare many variables on one line.
    Use
      int* p;
      int* q;
    instead of
      int *p, *q;
    The former declarations also allow you to describe each variable.

  * The include guard for src/somedir/foo.hh is
    SPOT_SOMEDIR_FOO_HH


Naming
======

  * Functions, methods, types, classes, etc. are named with lowercase
    letters, using an underscore to separate words.

      int compute_this_and_that();

      class this_is_a_class;

      typedef int int_array[];

    That is the style used in STL.

  * Private members end with an underscore.

    class my_class
    {
    public:
      ...
      int get_val() const;
    private:
      int name_;
    };

  * Identifiers (even internal) starting with `_' are best avoided
    to limit clashes with system definitions.

  * Template arguments use capitalized name, with joined words.

    template <class T, int NumberOfThings>
    class foo
    {
      ...
    };

  * Enum members also use capitalized name, with joined words.

  * C Macros are all uppercase.


Other style recommandations
===========================

  * Do not use the NULL macro, it is not always implemented in a way
    which is compatible with all pointer types.  Always use 0 instead.

  * Limit the scope of local variables by defining them as late as
    possible.  Do not reuse a local variables for two different things.

  * Do not systematically initialise local variables with 0 or other
    meaningless values.  This hides errors to valgrind.

  * Avoid <iostream>, <ostream>, etc. in headers whenever possible.
    Prefer <iosfwd> when predeclarations are sufficient, and then
    use for instance use just <ostream> in the corresponding .cc file.
    (A plain <iostream> is needed when using std::cout, std::cerr, etc.)

  * Always declare helper functions and other local class definitions
    (used in a single .cc files) in anonymous namespaces.  (The risk
    otherwise is to declare two classes with the same name: the linker
    will ignore one of the two silently.  The resulting bugs are often
    difficult to understand.)