/* Module management. */

/* ---------------------------- Specification ----------------------------- */

/* An executable can be built up of any number of modules. The main and
 first module is called "clisp". All modules have a specific subr_tab
 and a specific object_tab. The objects in these tables are saved in
 the mem file.
 There's a subtle bootstrapping involved with these tables:
 Let S denote a module set and M a new module.
 1. Start with lisp.run (S) and lispinit.mem (S). If M needs some specific
    packages to be defined, define them and re-save lispinit.mem (S).
 2. Build lisp.run (S+M). Run lisp.run (S+M) with lispinit.mem (S).
    The tables of S will be initialized from the mem file, whereas the
    tables of M will be initialized freshly. Save as lispinit.mem (S+M).
 3. Now run lisp.run (S+M) with lispinit.mem (S+M).
    The tables of S+M will be initialized from the mem file. */

/* Initialize the module system. */
local void init_modules_0 (void);

/* The main module, called "clisp". */
extern module_t main_module;

/* Iterate through the modules.
 for_modules(which,statement);
 which = either `all_modules'
         or     `all_other_modules' (means all except main_module).
 A variable `module' of type module_t* must be declared; it will be used
 as the iteration variable and can use within statement. */

#ifdef DYNAMIC_MODULES
/* Register a new module. */
global void add_module (module_t * new_module);
#endif

/* find a module with the given name */
extern module_t* find_module (const char *name);
/* push all module names to STACK and return the number of modules pushed
 can trigger GC */
extern uintC modules_names_to_stack (void);

/* --------------------------- Implementation ----------------------------- */

/* These are defined in modules.d (which is re-compiled for
   every linking set). */
extern uintC module_count;
extern module_t modules[];

#define main_module  modules[0]

#ifdef DYNAMIC_MODULES

/* A pointer to the last element of the module list. */
local module_t ** last_module;

local void init_modules_0 (void)
{
  var module_t* module = &modules[0];
  while (module[1].name != NULL) {
    module->next = module+1; module++;
  }
  *(last_module = &module->next) = NULL;
}

global void add_module (module_t * module)
{
  *last_module = module; last_module = &module->next;
  module_count++;
}

#define for_modules(which,statement)                                    \
  module = (which); while (module!=NULL) { statement; module = module->next; }
#define all_modules  &main_module
#define all_other_modules  main_module.next

#else

#define for_modules(which,statement)                                    \
  module = (which); until (module->name==NULL) { statement; module++; }
#define all_modules  &modules[0]
#define all_other_modules  &modules[1]

#define init_modules_0()

#endif

/* find the module with the given name */
global module_t* find_module (const char *name)
{
  var module_t* module;
  for_modules(all_modules, {
    if (asciz_equal(name,module->name)) return module;
  });
  return NULL;
}

/* push all module names to STACK and return the number of modules pushed
 can trigger GC */
extern uintC modules_names_to_stack (void)
{
  var uintC count = 0;
  var module_t* module;
  for_modules(all_modules, {
    pushSTACK(asciz_to_string(module->name,O(misc_encoding)));
    count++;
  });
  return count;
}

