NAME
        block

DESCRIPTION
        A block is a special statment, that begins with '{', contains
        a list of statements, and ends with '}'.

        The block may define local variables. If for a variable no
        initialisation is given, the variable is initialised to 0 every
        time the block is entered. Otherwise, the initialisation
        expression is evaluated and its result assigned to the variable
        everytime the block is entered.

        Example definitions are:

          int i;
          int j = 3;
          int k = 3 * j, l;

          Here, i and l are both initialised to 0; j is initialised
          to 3, and k is initialised to 9 (3 * j).

        Local variables defined in a block are visible only until the
        end of the block. Definitions in an inner block hide definitions in
        outer blocks.

HISTORY
        Up to 3.2.7 local variables were visible (from their point of
        definition) in the whole function. That is, code like

            do {
                int res;

                res = ...
            } while (res == 5);
            write(res);

        was perfectly legal. It is no longer, as 'res' ceases to exist
        with the closing '}' of the while().

        Up to 3.5.0 you could get this old behaviour back with the 
        #pragma no_local_scopes and switch it off again with 
        #pragma local_scopes.

        Since 3.5.0 it is not possible to disable the local scope behaviour.

        Up to 3.2.8, local variables could not be initialised in their
        definition.