/*  $Id$

    Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (C): 1985-2002, University of Amsterdam

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <h/kernel.h>
#include <h/text.h>
#include <itf/c.h>
#include <h/interface.h>		/* hostCallProc() */

static status	recordInstancesClass(Class class, BoolObj keep, BoolObj recursive);
static status	fill_slots_class(Class class, Class super);
static Variable	getLocaliseInstanceVariableClass(Class class, Name name);
static Any	bindMethod(Class class, Name code, Name selector);
static status	lazyBindingClass(Class class, Name which, BoolObj val);

#define CLASS_PCE_SLOTS 42

#define InstanceSize(c)	((int)(intptr_t) &((Instance) NULL)->slots[valInt((c)->slots)])
#define SlotsClass(c) \
      ((sizeof(struct c) - ((intptr_t) &((Instance) NULL)->slots[0])) / sizeof(Any))

static void
resetSlotsClass(Class class, Name name)
{ size_t i;
  size_t slots = SlotsClass(class);

  setProtectedObj(class);

  for(i=0; i<CLASS_PCE_SLOTS; i++)
    ((Instance)class)->slots[i] = CLASSDEFAULT;
  for( ; i < slots; i++ )
    ((Instance)class)->slots[i] = NULL;

  class->resolve_method_message = DEFAULT;
  class->created_messages       = NIL;
  class->freed_messages         = NIL;
  class->make_class_message     = NIL;
  class->instances              = NIL;
  class->super_class            = NIL;
  class->sub_classes            = NIL;

  assign(class, name,	    name);
  assign(class, no_created, ZERO);
  assign(class, no_freed,   ZERO);
}


Class
typeClass(Name name)
{ Class class = alloc(sizeof(struct class));

  initHeaderObj(class, ClassClass);
  resetSlotsClass(class, name);

  return class;
}


Class
nameToTypeClass(Name name)
{ Type type;

  if ( (type = nameToType(name)) )
  { if ( !inBoot &&
	 ( !isClassType(type) ||
	   type->vector != OFF ||
	   notNil(type->supers)
	 ) )
    { errorPce(type, NAME_notClassType);
      fail;
    }

    if ( !instanceOfObject(type->context, ClassClass) )
    { if ( type->context == name )
      { assign(type, context, typeClass(name));
      } else
      { errorPce(type, NAME_notClassType);
	fail;
      }
    }

    return type->context;
  }

  fail;
}


static void
linkSubClass(Class super, Class sub)
{ if ( isNil(super->sub_classes) )
  { assign(super, sub_classes, newObject(ClassChain, sub, EAV));
  } else
  { Cell cell;
    int done = FALSE;

    for_cell(cell, super->sub_classes)
    { Class class = cell->value;

      if ( class->name == sub->name )
      { if ( class != sub )
	  deleteChain(super->sub_classes, class);
        else
	  done = TRUE;
      }
    }

    if ( !done )
      appendChain(super->sub_classes, sub);
  }

  assign(sub, super_class, super);
}


static void
defaultAssocClass(Class class)
{ static Name suffix;

  if ( !suffix )
    suffix = CtoName("_class");

  newAssoc(getAppendName(class->name, suffix), class);
}



Class
defineClass(Name name, Name super, StringObj summary, SendFunc makefunction)
{ Class class, superclass;

  TRY(class = nameToTypeClass(name));
  class->make_class_function = makefunction;
  if ( notNil(super) )
  { TRY(superclass = nameToTypeClass(super));
    linkSubClass(superclass, class);
  }
  if ( isClassDefault(class->creator) )
    assign(class, creator, inBoot ? NAME_builtIn : NAME_host);
  if ( notDefault(summary) )
    assign(class, summary, summary);

  if ( notClassDefault(class->realised) )
    return class;			/* existing (boot) class */

  if ( isClassDefault(class->sub_classes) )
    assign(class, sub_classes, NIL);

  assign(class, realised, OFF);
  defaultAssocClass(class);
  appendHashTable(classTable, name, class);
  protectObject(class);
  createdObject(class, NAME_new);

  return class;
}


status
defineClasses(struct class_definition *classes)
{ for(; classes->name; classes++)
  { Class class = defineClass(classes->name, classes->super,
			      staticCtoString(classes->summary),
			      classes->makefunction);

    if ( classes->global )
      *classes->global = class;
  }

  numberTreeClass(ClassObject, 0);

  succeed;
}


static inline status
call_make_function(SendFunc f, Class class)
{ status rval;

  rval = (*f)(class);

  return rval;
}


status
realiseClass(Class class)
{ if ( class->realised != ON )
  { status rval;

    DEBUG_BOOT(Cprintf("Realising class %s ... ", strName(class->name)));

    if ( notNil(class->super_class) )
      TRY(realiseClass(class->super_class));

    ServiceMode(PCE_EXEC_SERVICE,
	 if ( class->make_class_function )
	 { assign(class, realised, ON);
	   rval = (fill_slots_class(class, class->super_class) &&
		   call_make_function(class->make_class_function, class) &&
		   initClass(class));
	 } else
	   rval = FAIL;);

    DEBUG_BOOT(Cprintf("%s\n", rval ? "ok" : "FAILED"));

    return rval;
  }

  succeed;
}


void
bindNewMethodsClass(Class class)
{ if ( isDefault(class->lookup_method) ||
       isDefault(class->initialise_method) )
  { GetMethod l = getGetMethodClass(class, NAME_lookup);
    Any       s = getSendMethodClass(class, NAME_initialise);

    assert(instanceOfObject(s, ClassSendMethod));

    if ( l )
      setDFlag(l, D_TYPENOWARN);
    else
      l = NIL;

    assign(class, lookup_method, l);
    assign(class, initialise_method, s);
  }
}


status
realiseBootClass(Class class)
{ assign(class, realised, OFF);

  realiseClass(class);
  bindMethod(class, NAME_send, NAME_initialise);
  bindMethod(class, NAME_get,  NAME_lookup);
  deleteHashTable(class->send_table, NAME_initialise);
  deleteHashTable(class->get_table,  NAME_lookup);
  assign(class, lookup_method,     DEFAULT);
  assign(class, initialise_method, DEFAULT);

  succeed;
}


static status
fill_slots_class(Class class, Class super)
{ if ( notNil(super) )
    linkSubClass(super, class);

  initialiseProgramObject(class);

  setDFlag(class, DC_LAZY_GET|DC_LAZY_SEND);
#ifdef O_CPLUSPLUS
  if ( class->creator == name_cxx )
    setDFlag(class, D_CXX);
#endif

  assign(class, realised,             ON);
  assign(class, send_methods,         newObject(ClassChain, EAV));
  assign(class, get_methods,          newObject(ClassChain, EAV));
  assign(class, class_variables,      newObject(ClassChain, EAV));
  assign(class, send_table,           newObject(ClassHashTable, EAV));
  assign(class, get_table,            newObject(ClassHashTable, EAV));
  assign(class, local_table,          newObject(ClassHashTable, EAV));
  assign(class, class_variable_table, NIL);
  assign(class, selection_style,      NIL);
  assign(class, rcs_revision,	      NIL);
  assign(class, source,		      NIL);
  if ( isClassDefault(class->summary) )
    assign(class, summary, NIL);

					/* special method cache */
  assign(class, send_catch_all,	   DEFAULT);
  assign(class, get_catch_all,	   DEFAULT);
  assign(class, convert_method,	   DEFAULT);
  if ( !class->boot )
  { assign(class, initialise_method, DEFAULT);
    assign(class, lookup_method,     DEFAULT);
  }

  class->send_function     = NULL;
  class->get_function      = NULL;
  class->c_declarations    = NULL;

  if ( notNil(super) )
  { assign(class, term_names,	        super->term_names);
    assign(class, delegate,	        getCopyChain(super->delegate));
    assign(class, instance_variables,   getCopyVector(super->instance_variables));
    assign(class, cloneStyle,	        super->cloneStyle);
    assign(class, saveStyle,	        super->saveStyle);
    assign(class, features,		getCopySheet(super->features));
    assign(class, solid,	        super->solid);
    assign(class, handles,	        getCopyChain(super->handles));
    assign(class, un_answer,	        super->un_answer);
    assign(class, slots,	        super->slots);

    if ( !class->boot )
    { assign(class, instance_size,	super->instance_size);
      assign(class, init_variables,     super->init_variables);
    }
    assign(class, changed_messages,     getCopyChain(super->changed_messages));
    assign(class, created_messages,     getCopyChain(super->created_messages));
    assign(class, freed_messages,       getCopyChain(super->freed_messages));
    if ( isDefault(class->resolve_method_message) )
      assign(class, resolve_method_message, super->resolve_method_message);

    if ( notNil(super->instances) )
      recordInstancesClass(class, ON, OFF);

    class->saveFunction			= super->saveFunction;
    class->loadFunction			= super->loadFunction;
    class->cloneFunction		= super->cloneFunction;
    class->redrawFunction		= super->redrawFunction;
    class->changedFunction		= super->changedFunction;
    class->in_event_area_function	= super->in_event_area_function;
  } else
  { assign(class, term_names,	        NIL);
    assign(class, delegate,	        newObject(ClassChain, EAV));
    assign(class, instance_variables,	newObject(ClassVector, EAV));
    assign(class, cloneStyle,	        NAME_recursive);
    assign(class, saveStyle,	        NAME_normal);
    assign(class, features,		NIL);
    assign(class, solid,	        OFF);
    assign(class, instance_size,        toInt(sizeof(struct object)));
    assign(class, slots,	        ZERO);
    assign(class, un_answer,	        ON);
    assign(class, handles,		NIL);
    assign(class, changed_messages,	NIL);
    assign(class, resolve_method_message, NIL);

    assign(class, init_variables,	NAME_static);
    assign(class, changed_messages,     NIL);
    assign(class, created_messages,     NIL);
    assign(class, freed_messages,       NIL);
  }

  defaultAssocClass(class);
  appendHashTable(classTable, class->name, class);
  protectObject(class);

  succeed;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
bootClass() should be called to  initialise the most  vital classes of
the system.

Note that the initialise_method  is locked to  prevent drop-out during
the real class definition: freeObject doesn't yet work properly.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static Class
_bootClass(Name name, Name super_name,
	   int size, int slots,
	   SendFunc initF,
	   int argc, va_list args)
{ Type type = nameToType(name);
  Class cl = type->context;
  Class super;

  if ( notNil(super_name) )
  { Type super_type = nameToType(super_name);
    super = super_type->context;
    assert(notNil(super->initialise_method)); /* No super-class */
  } else
    super = NIL;

  DEBUG_BOOT(Cprintf("Boot Class %s ... ", pp(name)));

  cl->boot = slots;
  if ( notNil(super) )
    cl->boot += super->boot;

  assign(cl, realised, ON);
  assign(cl, super_class, super);
  assign(cl, instance_size, toInt(size));
  assign(cl, slots, toInt((size - ((intptr_t) &((Instance) NULL)->slots[0]))
			   / sizeof(Any)));

  { int i;
    Type types[VA_PCE_MAX_ARGS];
    Vector tv;

    for(i=0; i<argc; i++)
    { char *type = va_arg(args, char *);

      if ( !(types[i] = CtoType(type)) )
	sysPce("Bad type in bootClass(): %s: %s\n", pp(name), type);
    }

    tv = createVectorv(argc, (Any *)types);

    assign(cl, initialise_method,
	   createSendMethod(NAME_initialise, tv, NIL, initF));
    lockObj(cl->initialise_method);	/* avoid reclaim on sdcClass */
    assign(cl, lookup_method, NIL);
    assign(cl, init_variables, NAME_static); /* not support for boot stuff */
    assign(cl, resolve_method_message, NIL);
  }

  DEBUG_BOOT(Cprintf("ok\n"));

  return cl;
}


Class
bootClass(Name name, Name super_name, int size, int slots,
	  SendFunc newF, int argc, ...)
{ va_list args;
  Class class;

  va_start(args, argc);
  class = _bootClass(name, super_name, size, slots, newF, argc, args);
  va_end(args);

  return class;
}


void
lookupBootClass(Class class, Func f, int argc, ...)
{ int i;
  Type types[VA_PCE_MAX_ARGS];
  Vector tv;
  va_list args;
  GetMethod m;

  va_start(args, argc);
  for(i=0; i<argc; i++)
  { char *type = va_arg(args, char *);

    if ( !(types[i] = CtoType(type)) )
      sysPce("Bad type in lookupBootClass(): %s: %s",
	     pp(class->name), type);
  }
  va_end(args);

  tv = createVectorv(argc, (Any *)types);
  m = createGetMethod(NAME_lookup, TypeAny, tv, NIL, f);
  lockObj(m);				/* avoid reclaim on sdcClass */
  setDFlag(m, D_TYPENOWARN);

  assign(class, lookup_method, m);
}


Class
getConvertClass(Class class_class, Any obj)
{ Class class;
  Name name;

  if ( instanceOfObject(obj, ClassClass) )
    return obj;

  if ( instanceOfObject(obj, ClassType) )
  { Type t = obj;

    if ( isClassType(t) )
      return t->context;
  }

  if ( (name = toName(obj)) )
  { if ( !(class = getMemberHashTable(classTable, name)) )
    { exceptionPce(PCE, NAME_undefinedClass, name, EAV);
      if ( !(class = getMemberHashTable(classTable, name)) )
	fail;
    }

    return class;
  }

  fail;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Called from clearCacheClass().  Change this if this class is to do anything
else ...
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static status
installClass(Class class)
{ if ( ClassFunction && isAClass(class, ClassFunction) )
  { Cell cell;
    Class cl;

    for(cl = class; ; cl = cl->super_class)
    { if ( onDFlag(class, DC_LAZY_SEND) )
	lazyBindingClass(cl, NAME_send, OFF);
      if ( onDFlag(class, DC_LAZY_GET) )
	lazyBindingClass(cl, NAME_get, OFF);

      for_cell(cell, cl->send_methods)
      { SendMethod m = cell->value;

	if ( !getMemberHashTable(class->send_table, m->name) )
	  getResolveSendMethodClass(class, m->name);
      }

      for_cell(cell, cl->get_methods)
      { GetMethod m = cell->value;

	if ( !getMemberHashTable(class->get_table, m->name) )
	  getResolveGetMethodClass(class, m->name);
      }

      for_vector(cl->instance_variables, Variable v,
		 { if ( sendAccessVariable(v) )
		     getResolveSendMethodClass(class, v->name);
		   if ( getAccessVariable(v) )
		     getResolveGetMethodClass(class, v->name);
		 });

      if ( cl == ClassFunction )
	break;
    }
  } else if ( ClassGraphical && isAClass(class, ClassGraphical) )
  { bindMethod(class, NAME_send, NAME_inEventArea);
  }

  succeed;
}

status
initClass(Class class)
{ class->boot = 0;

#if 0
  if ( InstanceSize(class) != valInt(class->instance_size) ) /* TBD */
    Cprintf("Class %s has %d alien slots\n",
	    pp(class->name),
	    (valInt(class->instance_size) - InstanceSize(class)) /
	    sizeof(Any));
#endif

  return installClass(class);
}


		/********************************
		*     USER-DEFINED CLASSES	*
		********************************/

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Creating classes.  Hairy.  Actually it is getLookupClass() that takes
care of ceating new classes.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static status
initialiseClass(Class class, Name name, Class super)
{ Type type;
  Class cl;

  if ( (cl = getMemberHashTable(classTable, name)) &&
       instanceOfObject(cl, ClassClass) )
    fail;				/* failure from getLookupClass() */

  resetSlotsClass(class, name);
  appendHashTable(classTable, name, class);

  type = nameToType(name);
  if ( !isClassType(type) ||
       type->vector != OFF ||
       notNil(type->supers) )
  { errorPce(type, NAME_notClassType);
    fail;
  }
  assign(type, context, class);

  if ( isDefault(super) )
    super = ClassObject;

  realiseClass(super);
  fill_slots_class(class, super);
  assign(class, creator, inBoot ? NAME_builtIn : NAME_host);
  assign(class, no_created, ZERO);
  assign(class, no_freed,   ZERO);
  numberTreeClass(ClassObject, 0);

  succeed;
}


static Class
getLookupClass(Class class, Name name, Class super)
{ Class cl;

  if ( (cl = getMemberHashTable(classTable, name)) )
  { if ( notNil(cl->super_class) )	/* no longer a typeClass() */
    { if ( isDefault(super) || cl->super_class == super )
	answer(cl);

      errorPce(cl, NAME_cannotChangeSuperClass);
      fail;
    }
    if ( name == NAME_object )		/* class(object) has no super! */
      answer(cl);
  } else if ( isDefault(super) )	/* lookup: class(box) or so */
  { exceptionPce(PCE, NAME_undefinedClass, name, EAV);
    if ( (cl = getMemberHashTable(classTable, name)) )
      answer(cl);
  }

  fail;
}


static status
unlinkClass(Class cl)
{ assert(0);				/* classes cannot be unlinked */
  fail;
}


static Class
getSubClassClass(Class super, Name name)
{ realiseClass(super);

  if ( notNil(super->sub_classes) )
  { Cell cell;

    for_cell(cell, super->sub_classes)
    { Class sub = cell->value;

      if ( sub->name == name )
	answer(sub);
    }
  }

  answer(newObject(super->class, name, super, EAV));
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Adding local variables to classes
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static void
fixSubClassVariableClass(Class class, Variable old, Variable new)
{ if ( class->realised == ON )
  { Cell cell;
    Int offset = new->offset;

    unallocInstanceProtoClass(class);

    if ( (getElementVector(class->instance_variables, offset) == old) || !old )
    { deleteHashTable(class->get_table,   new->name);
      deleteHashTable(class->send_table,  new->name);
      deleteHashTable(class->local_table, new->name);

      elementVector(class->instance_variables, offset, new);

					/* TBD: function subclass? */
      if ( old && notNil(class->sub_classes) )
      { for_cell(cell, class->sub_classes)
	  fixSubClassVariableClass(cell->value, old, new);
      }
    }
  }
}


static Variable
getLocaliseInstanceVariableClass(Class class, Name name)
{ Variable var;

  realiseClass(class);
  if ( (var = getInstanceVariableClass(class, name)) )
  { if ( var->context != class )
    { Variable var2 = getCloneObject(var);
      assign(var2, context, class);
      fixSubClassVariableClass(class, var, var2);

      if ( ClassDelegateVariable &&
	   instanceOfObject(var2, ClassDelegateVariable) )
	delegateClass(class, var2->name);

      answer(var2);
    }
  }

  answer(var);
}

status
instanceVariableClass(Class class, Variable var)
{ Variable old;
  Int offset;

  realiseClass(class);
					/* redefinition of a variable */
  if ( (old = getInstanceVariableClass(class, var->name)) )
  { if ( old->context != class &&
	 !specialisedType(var->type, old->type) )
      return errorPce(class, NAME_cannotRefineVariable, var->name);

    offset = old->offset;
  } else
  { if ( !inBoot )
    { if ( class->no_created != class->no_freed )
	return errorPce(class, NAME_hasInstances);
      if ( notNil(class->sub_classes) )
      { Cell cell;

	for_cell(cell, class->sub_classes)
	{ Class sub = cell->value;
	  if ( sub->realised == ON )
	    return errorPce(class, NAME_hasSubClasses);
	}
      }
    }
    offset = class->slots;
    assign(class, slots, toInt(valInt(class->slots)+1));
    if ( InstanceSize(class) > valInt(class->instance_size) )
      assign(class, instance_size, toInt(InstanceSize(class)));
  }

  assign(var, offset, offset);
  assign(var, context, class);
  fixSubClassVariableClass(class, old, var);

  if ( ClassDelegateVariable && instanceOfObject(var, ClassDelegateVariable) )
    delegateClass(class, var->name);

  succeed;
}


static status
refineVariableClass(Class class, Variable var)
{ Variable old;

  if ( !(old = getInstanceVariableClass(class, var->name)) )
    return instanceVariableClass(class, var); /* no redefinition (error?) */

  assign(var, offset, old->offset);
  assign(var, context, class);
  fixSubClassVariableClass(class, old, var);

  if ( ClassDelegateVariable && instanceOfObject(var, ClassDelegateVariable) )
    delegateClass(class, var->name);

  succeed;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Method manipulation
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static status
codeExecuteCode(Code c)
{ return vm_send(c, NAME_Execute, classOfObject(c), 0, NULL);
}


void
fixSendFunctionClass(Class class, Name selector)
{ SendMethod m = getSendMethodClass(class, selector);

  class->send_function = (m ? (SendFunc) m->function : (SendFunc) NULL);

  if ( !class->send_function )
    class->send_function = codeExecuteCode;
}


static Any
codeGetExecuteCode(Code c)
{ return vm_get(c, NAME_Execute, classOfObject(c), 0, NULL);
}


void
fixGetFunctionClass(Class class, Name selector)
{ GetMethod m = getGetMethodClass(class, selector);

  class->get_function = (m ? (GetFunc) m->function : (GetFunc) NULL);

  if ( !class->get_function )
    class->get_function = codeGetExecuteCode;
}


static void
fixSubClassSendMethodsClass(Class class, Method m)
{ if ( class->realised == ON )
  { Cell cell;

    deleteHashTable(class->send_table, m->name);
    if ( notNil(class->sub_classes) )
    { for_cell(cell, class->sub_classes)
	fixSubClassSendMethodsClass(cell->value, m);
    }
    if ( m->name == NAME_initialise )
      assign(class, initialise_method, DEFAULT);
    else if ( m->name == NAME_catchAll )
      assign(class, send_catch_all, DEFAULT);
    else if ( m->name == NAME_inEventArea )
      class->in_event_area_function = INVOKE_FUNC;
  }
}


status
sendMethodClass(Class class, SendMethod m)
{ Cell cell;

  realiseClass(class);

  if ( notNil(m->context) )
    return errorPce(class, NAME_alreadyPartOf, m, m->context);

  fixSubClassSendMethodsClass(class, (Method) m);
  for_cell(cell, class->send_methods)
  { SendMethod old = cell->value;

    if ( old->name == m->name && old != m )
    {
#ifndef O_RUNTIME
      deleteChain(class->send_methods, old);
#else
      if ( onFlag(old, F_TEMPLATE_METHOD) )
	deleteChain(class->send_methods, old);
      else
	return errorPce(getMethodFromFunction(sendMethodClass),
			NAME_runtimeVersion);
#endif
      break;
    }
  }

  appendChain(class->send_methods, m);
  assign(m, context, class);
  if ( m->name == NAME_equal )
    setDFlag(m, D_TYPENOWARN);
  if ( offDFlag(class, DC_LAZY_SEND) )
    lazyBindingClass(class, NAME_send, ON);

  succeed;
}


static void
fixSubClassGetMethodsClass(Class class, Method m)
{ if ( class->realised == ON && !inBoot ) /* TBD */
  { Cell cell;

    deleteHashTable(class->get_table, m->name);
    if ( notNil(class->sub_classes) )
    { for_cell(cell, class->sub_classes)
	fixSubClassGetMethodsClass(cell->value, m);
    }
    if ( m->name == NAME_lookup )
      assign(class, lookup_method, DEFAULT);
    else if ( m->name == NAME_convert )
      assign(class, convert_method, DEFAULT);
  }
}

status
getMethodClass(Class class, GetMethod m)
{ Cell cell;

  realiseClass(class);

  if ( notNil(m->context) )
    return errorPce(class, NAME_alreadyPartOf, m, m->context);

					/* delete old definition */
  fixSubClassGetMethodsClass(class, (Method) m);

  for_cell(cell, class->get_methods)
  { GetMethod old = cell->value;

    if ( old->name == m->name && old != m )
    {
#ifndef O_RUNTIME
      deleteChain(class->get_methods, old);
#else
      if ( onFlag(old, F_TEMPLATE_METHOD) )
	deleteChain(class->get_methods, old);
      else
	return errorPce(getMethodFromFunction(sendMethodClass),
			NAME_runtimeVersion);
#endif
      break;
    }
  }
					/* Insert new one */
  appendChain(class->get_methods, m);
  assign(m, context, class);
  if ( offDFlag(class, DC_LAZY_GET) )
    lazyBindingClass(class, NAME_get, ON);

  succeed;
}


status
setChangedFunctionClass(Class class, SendFunc func)
{ class->changedFunction = func;

  succeed;
}


status
setInEventAreaFunctionClass(Class class, SendFunc func)
{ class->in_event_area_function = func;

/* TBD, but implementation needs to be cleaned first
  sendMethod(class, NAME_inEventArea, NAME_event, 2, "x=int", "y=int",
	     "Test if location is in sensitive area",
	     func);
*/

  succeed;
}


status
isPceSlot(Class class, int n)
{ Variable var = class->instance_variables->elements[n];

  return var->type->kind == NAME_alien ? FAIL : SUCCEED;
}


status
allPceSlotsClass(Class class)
{ for_vector(class->instance_variables, Variable var,
	     if ( var->type->kind == NAME_alien )
	       fail;);

  succeed;
}

		/********************************
		*        OBJECT -> TERM		*
		********************************/

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
termClass(Class, FunctorName, Arity, Selector1 ...)
    Define the term representation of Class to be

	FunctorName(obj?Selector1, ...)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static inline void
_termClass(Class class, char *name, int argc, va_list args)
{ realiseClass(class);

  if ( argc == ARGC_UNKNOWN )
  { assign(class, term_names, NIL);
  } else
  { ArgVector(names, argc);
    int n;

    for(n=0; n<argc; n++)
    { names[n] = va_arg(args, Any);

      if ( !isProperObject(names[n]) || notName(names[n]) )
      { sysPce("Illegal selector (arg %d) to termClass of class %s",
	       n+1, pp(class->name));
	return;
      }
    }

    assign(class, term_names, newObjectv(ClassVector, argc, names));
  }
}


void
termClass(Class class, char *name, int argc, ...)
{ va_list args;

  va_start(args, argc);
  _termClass(class, name, argc, args);
  va_end(args);
}


status
sendMethodv(Class class, Name name, Name group, int argc, va_list args)
{ SendMethod m;
  Type types[METHOD_MAX_ARGS];
  int i;
  SendFunc f;
  Vector tv;
  char *rawdoc;
  StringObj doc;

  for(i=0; i<argc; i++)
  { char *type = va_arg(args, char *);

    assert(i < METHOD_MAX_ARGS);
    if ( !(types[i] = CtoType(type)) )
      sysPce("Bad type in sendMethod(): %s->%s: %s",
	     pp(class->name), pp(name), type);
  }

  tv = inBoot ? createVectorv(argc, (Any *)types)
              : answerObjectv(ClassVector, argc, (Any *)types);

  if ( (rawdoc = va_arg(args, char *)) )
  { checkSummaryCharp(class->name, name, rawdoc);
    doc = rawdoc[0] == EOS ? (StringObj) NIL : staticCtoString(rawdoc);
  } else
    doc = NIL;

  f = va_arg(args, SendFunc);
  m = createSendMethod(name, tv, doc, f);
  if ( notDefault(group) )
    assign(m, group, group);

  assign(m, context, class);
  appendChain(class->send_methods, m);

  if ( isNil(m->summary) )
  { SendMethod super;

    if ( (super = (SendMethod) getInheritedFromMethod((Method)m)) )
      assign(m, summary, super->summary);
  }

  succeed;
}


status
sendMethod(Class class, Name name, Name group, int argc, ...)
{ va_list args;
  status rval;

  va_start(args, argc);
  rval = sendMethodv(class, name, group, argc, args);
  va_end(args);

  return rval;
}


status
storeMethod(Class class, Name name, SendFunc function)
{ Variable var = getInstanceVariableClass(class, (Any) name);
  Vector tv;
  SendMethod m;

  if ( !var )
    return sysPce("storeMethod(): no variable %s on class %s",
		  pp(name), pp(class->name));
  tv = inBoot ? createVectorv(1, (Any *)(&var->type))
              : answerObjectv(ClassVector, 1, (Any *)(&var->type));

  m = createSendMethod(name, tv, var->summary, function);
  assign(m, context, class);
  assign(m, group, var->group);
  appendChain(class->send_methods, m);

  succeed;
}


static status
fetchMethod(Class class, Name name, void *function)
{ Variable var = getInstanceVariableClass(class, (Any) name);
  Vector tv;
  GetMethod m;

  if ( !var )
    return sysPce("fetchMethod(): no variable %s on class %s",
		  pp(name), pp(class->name));
  tv = inBoot ? createVectorv(0, NULL)
              : answerObjectv(ClassVector, 0, NULL);

  m = createGetMethod(name, var->type, tv, var->summary, function);
  assign(m, context, class);
  assign(m, group, var->group);
  appendChain(class->get_methods, m);

  succeed;
}


status
getMethodv(Class class, Name name, Name group,
	   const char *rtype, int argc, va_list args)
{ GetMethod m;
  Type rt;
  Type types[METHOD_MAX_ARGS];
  int i;
  Func f;
  Vector tv;
  char *rawdoc;
  StringObj doc;

  if ( !(rt = CtoType(rtype)) )
    return sysPce("Bad return type in getMethod(): %s<-%s: %s",
		  pp(class->name), pp(name), rtype);
  for(i=0; i<argc; i++)
  { char *type = va_arg(args, char *);

    assert(i<METHOD_MAX_ARGS);
    if ( !(types[i] = CtoType(type)) )
      sysPce("Bad type in getMethod(): %s<-%s: %s",
	     pp(class->name), pp(name), type);
  }
  tv = inBoot ? createVectorv(argc, (Any *)types)
              : answerObjectv(ClassVector, argc, (Any *)types);

  if ( (rawdoc = va_arg(args, char *)) )
  { checkSummaryCharp(class->name, name, rawdoc);
    doc = rawdoc[0] == EOS ? (StringObj) NIL : staticCtoString(rawdoc);
  } else
    doc = NIL;

  f = va_arg(args, Func);
  m = createGetMethod(name, rt, tv, doc, f);
  if ( notDefault(group) )
    assign(m, group, group);

  assign(m, context, class);
  appendChain(class->get_methods, m);
  if ( isNil(m->summary) )
  { GetMethod super;

    if ( (super = (GetMethod) getInheritedFromMethod((Method)m)) )
      assign(m, summary, super->summary);
  }

  succeed;
}

status
getMethod(Class class, Name name, Name group, const char *rtype, int argc, ...)
{ va_list args;
  status rval;

  va_start(args, argc);
  rval = getMethodv(class, name, group, rtype, argc, args);
  va_end(args);

  return rval;
}


		/********************************
		*       RESERVED FUNCTIONS	*
		********************************/

status
cloneStyleClass(Class class, Name style)
{ realiseClass(class);
  assign(class, cloneStyle, style);

  succeed;
}


status
cloneStyleVariableClass(Class class, Name slot, Name style)
{ Variable var;

  if ( (var = getLocaliseInstanceVariableClass(class, slot)) )
    return cloneStyleVariable(var, style);

  fail;
}


status
saveStyleVariableClass(Class class, Name slot, Name style)
{ Variable var;

  if ( (var = getLocaliseInstanceVariableClass(class, slot)) )
    return saveStyleVariable(var, style);

  fail;
}


status
saveStyleClass(Class class, Name style)
{ realiseClass(class);
  assign(class, saveStyle, style);

  succeed;
}


status
setCloneFunctionClass(Class class, SendFunc function)
{ class->cloneFunction = function;
  succeed;
}


status
setRedrawFunctionClass(Class class, SendFunc function)
{ class->redrawFunction = function;

  sendMethod(class, NAME_RedrawArea, NAME_repaint, 1, "area",
	     "Repaint the argument area",
	     function);
  succeed;
}


status
setLoadStoreFunctionClass(Class class, SendFunc load, SendFunc store)
{ class->loadFunction = load;
  class->saveFunction = store;
  succeed;
}


static status
handleClass(Class class, Handle handle)
{ realiseClass(class);
  if ( isNil(class->handles) )
    assign(class, handles, newObject(ClassChain, handle, EAV));
  else
    appendChain(class->handles, handle);

  succeed;
}


status
solidClass(Class class, BoolObj val)
{ realiseClass(class);
  assign(class, solid, val);

  succeed;
}


status
sourceClass(Class class, SendFunc f, char *file, char *rcs)
{
#ifndef O_RUNTIME
  assign(class, source, newObject(ClassSourceLocation, CtoName(file), EAV));
#endif

  if ( rcs )
  { static char rev[] = "$Revision: ";
    char *s, *q;
    char buf[100];
    size_t l;

    for(s=rcs, q=rev; *q && *s == *q; s++, q++)
      ;
    strcpy(buf, s);
    l = strlen(buf);
    if ( l >= 2 && streq(&buf[l-2], " $") )
      buf[l-2] = EOS;

    assign(class, rcs_revision, CtoName(buf));
  }

  succeed;
}


#ifdef O_RUNTIME
static status
rtSourceClass(Class class, SourceLocation src)
{ succeed;
}
#endif


void
localClass(Class class, Name name, Name group,
	   char *type, Name access, char *doc)
{ Variable v;
  Type t;

  if ( !(t = CtoType(type)) )
    sysPce("Bad type in variable: %s.%s: %s",
	   pp(class->name), pp(name), type);

  v = createVariable(name, t, access);

  if ( strlen(doc) > 0 )
    assign(v, summary, staticCtoString(doc));
  if ( notDefault(group) )
    assign(v, group, group);

  instanceVariableClass(class, v);
}


static void
redefineLocalClass(Class class, Name name, Name group,
		   char *type, Name access, char *doc)
{ Variable v;
  Type t;

  if ( !(t = CtoType(type)) )
    sysPce("Bad type in variable: %s.%s: %s",
	   pp(class->name), pp(name), type);

  v = createVariable(name, t, access);

  if ( strlen(doc) > 0 )
    assign(v, summary, staticCtoString(doc));
  if ( notDefault(group) )
    assign(v, group, group);

  refineVariableClass(class, v);
}


static Name iv_access_names[] = { NAME_none, NAME_get, NAME_send, NAME_both };

status
declareClass(Class class, const classdecl *decls)
{ int i;
  const vardecl *iv;
  const classvardecl *cv;

  class->c_declarations = (classdecl *)decls; /* TBD: const */

  sourceClass(class, NULL, decls->source_file, decls->rcs_revision);
  if ( decls->term_arity != ARGC_INHERIT )
  { if ( decls->term_arity == ARGC_UNKNOWN )
    { assign(class, term_names, NIL);
    } else
    { assign(class, term_names,
	     newObjectv(ClassVector, decls->term_arity,
			(Any *)decls->term_names));
    }
  }

  for( i=decls->nvar, iv = decls->variables; i-- > 0; iv++ )
  { Name acs = iv_access_names[iv->flags & (IV_GET|IV_SEND)];

    if ( iv->flags & IV_REDEFINE )
      redefineLocalClass(class, iv->name, iv->group,
			 iv->type, acs, iv->summary);
    else
      localClass(class, iv->name, iv->group,
		 iv->type, acs, iv->summary);

    if ( iv->flags & IV_STORE )
      storeMethod(class, iv->name, (SendFunc) iv->context);
    else if ( iv->flags & IV_FETCH )
      fetchMethod(class, iv->name, (GetFunc) iv->context);
  }
					/* should be delayed too? */
  for( i=decls->nclassvars, cv=decls->class_variables; i-- > 0; cv++ )
  { if ( cv->type == RC_REFINE )
      refine_class_variable(class, strName(cv->name), cv->value);
    else
      attach_class_variable(class, cv->name, cv->type, cv->value, cv->summary);
  }

  succeed;
}


status
delegateClass(Class class, Name name)
{ Variable var = getInstanceVariableClass(class, name);

  if ( var )
  { deleteChain(class->delegate, var);
    appendChain(class->delegate, var);

    succeed;
  }

  return errorPce(class, NAME_noVariable, name);
}


status
prependDelegateClass(Class class, Name name)
{ Variable var = getInstanceVariableClass(class, name);

  if ( var )
  { deleteChain(class->delegate, var);
    prependChain(class->delegate, var);

    succeed;
  }

  return errorPce(class, NAME_noVariable, name);
}


static Any
getInstanceClassv(Class class, int argc, Any *argv)
{ answer(answerObjectv(class, argc, argv));
}


Variable
getInstanceVariableClass(Class class, Any which)
{ Variable var;

  realiseClass(class);

  if ( isInteger(which) )
    answer( getElementVector(class->instance_variables, (Int) which));

  if ( (var = getMemberHashTable(class->local_table, which)) != FAIL )
    answer(var);

  for_vector(class->instance_variables, var,
	     { if ( var->name == which )
	       { appendHashTable(class->local_table, which, var);
		 answer(var);
	       }
	     });

  fail;					/* no such variable */
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Lazy binding of methods.

We  donot  want  to  built   the    entire   method   representation  in
<-send_methods,  <-get_methods,  <-instance_variables,  <-get_table  and
<-send_table in one go. Many methods are   never used in an application,
and it would be good practice if   their definition is never loaded from
disk.

Therefore, a <-get_table and <-send_table start of empty. If a method is
needed, getSendMethodClass()/getGetMethodClass() is called,  which first
does  a  lookup  in  these  tables.  If    the   method  is  not  found,
getResolve(Send/Get)MethodClass() is called to find the method.

One       day,       the       implementation         was        simple.
getResolve(Send/Get)MethodClass() just walked  along   the  methods  and
variables and added the method or  var   to  the table when found,or the
constant @nil if the method was not found.

Right now, live is  harder  as   <-send_methods  and  <-get_methods  are
initially not filled either.  There  are   two  sources  of methods: the
classdecl  structure  from  <-c_declarations    and  the  host-language.
Moreover, the definitions in the host-language  may be change at runtime
(recompilation of sourcefiles).

Two cases need to be considered. Binding all (send- or get-) methods and
binding a single one. After all  methods   have  been  bound, no dynamic
binding is needed until the sources  are   changed.  If  a single method
needs to be bound, the system should first  check whether the host has a
more recent definition. If so, the host   should pass its definition. If
not, the current definition must be used.

To realise this, the class is  given   a  `generation number', and so is
each method. If a method needs  to   be  resolved, the system will first
check the method chain. If the method   chain contains a method with the
same generation as the class, this one is  used. If the number is older,
or the method is not known at  all,   the  host binder is called. If the
host binder fails, the built-in binder is called. If this fails too, the
instance variables are checked.

class->clear_cache increments the generation number of the class.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

static status
boundSendMethodClass(Class class, Name name)
{ if ( class->realised == ON )
  { Cell cell;

    for_cell(cell, class->send_methods)
    { SendMethod m = cell->value;

      if ( m->name == name )
	succeed;
    }
    for_vector(class->instance_variables, Variable var,
	       { if ( var->name == name &&
		      sendAccessVariable(var) &&
		      var->context == class )
		   succeed;
	       });
  }

  fail;
}


static status
boundGetMethodClass(Class class, Name name)
{ if ( class->realised == ON )
  { Cell cell;

    for_cell(cell, class->get_methods)
    { SendMethod m = cell->value;

      if ( m->name == name )
	succeed;
    }
    for_vector(class->instance_variables, Variable var,
	       { if ( var->name == name &&
		      getAccessVariable(var) &&
		      var->context == class )
		   succeed;
	       });
  }

  fail;
}


static SendMethod
attachLazySendMethodClass(Class class, const senddecl *sm)
{ SendMethod m;
  Type types[METHOD_MAX_ARGS];
  int i;
  Vector tv;
  StringObj doc;
  char **tps = (sm->arity == 1 ? (char **)&sm->types : (char **)sm->types);
  Cell cell;

  for_cell(cell, class->send_methods)
  { SendMethod m = cell->value;
    if ( m->name == sm->name )
      return m;
  }
  for(i=0; i<sm->arity; i++)
  { if ( !(types[i] = CtoType(tps[i])) )
      sysPce("Bad type in argument %d of %s->%s: %s",
	     i+1, pp(class->name), pp(sm->name), tps[i]);
  }

  tv = inBoot ? createVectorv(sm->arity, (Any *)types)
              : answerObjectv(ClassVector, sm->arity, (Any *)types);
  doc = (sm->summary ? (Any) staticCtoString(sm->summary) : DEFAULT);
  m = createSendMethod(sm->name, tv, doc, sm->function);
  if ( notDefault(sm->group) )
    assign(m, group, sm->group);

  appendChain(class->send_methods, m);
  assign(m, context, class);
  if ( m->name == NAME_equal )
    setDFlag(m, D_TYPENOWARN);

  return m;
}


static GetMethod
attachLazyGetMethodClass(Class class, const getdecl *gm)
{ GetMethod m;
  Type types[METHOD_MAX_ARGS];
  Type rtype;
  int i;
  Vector tv;
  StringObj doc;
  char **tps = (gm->arity == 1 ? (char **)&gm->types : (char **)gm->types);
  Cell cell;

  for_cell(cell, class->get_methods)
  { GetMethod m = cell->value;
    if ( m->name == gm->name )
      return m;
  }
  for(i=0; i<gm->arity; i++)
  { if ( !(types[i] = CtoType(tps[i])) )
      sysPce("Bad type in argument %d of %s<-%s: %s",
	     i+1, pp(class->name), pp(gm->name),tps[i]);
  }
  if ( !(rtype = CtoType(gm->rtype)) )
  { sysPce("Bad return-type in %s<-%s: %s",
	   pp(class->name), pp(gm->name), gm->rtype);
  }

  tv = inBoot ? createVectorv(gm->arity, (Any *)types)
              : answerObjectv(ClassVector, gm->arity, (Any *)types);
  doc = (gm->summary ? (Any) staticCtoString(gm->summary) : DEFAULT);
  m = createGetMethod(gm->name, rtype, tv, doc, gm->function);
  if ( notDefault(gm->group) )
    assign(m, group, gm->group);

  appendChain(class->get_methods, m);
  assign(m, context, class);

  return m;
}

static int bind_nesting;

void
resetMessageResolve()
{ bind_nesting = 0;
}

static Any
bindMethod(Class class, Name code, Name selector)
{ Any c;
  status rval = FAIL;
  classdecl *cdecls = class->c_declarations;
  int i;

  if ( isDefault(selector) && cdecls )
  { if ( code == NAME_send )
    { const senddecl *sm;

      for( i = cdecls->nsend, sm = cdecls->send_methods; i-- > 0; sm++ )
	attachLazySendMethodClass(class, sm);
    } else
    { const getdecl *gm;

      for( i = cdecls->nget, gm = cdecls->get_methods; i-- > 0; gm++ )
	attachLazyGetMethodClass(class, gm);
    }
  }

  if ( !bind_nesting )
  { bind_nesting++;
    if ( notNil((c=class->resolve_method_message)) && notDefault(c) )
    { if ( instanceOfObject(c, ClassCode) )
      { DEBUG(NAME_class,
	      Cprintf("Asking host to resolve %s %s %s\n",
		      pp(code), pp(class->name), pp(selector)));
	rval = forwardCode(c, code, class->name, selector, EAV);
      }
    }
    bind_nesting--;
  }

  if ( isDefault(selector) )
    return DEFAULT;

  if ( rval )
  { Chain ch = (code == NAME_send ? class->send_methods : class->get_methods);
    Cell cell;
    Method m = getTailChain(ch);

    if ( m && m->name == selector )	/* this will be the common case! */
      return m;

    for_cell(cell, ch)
    { Method m = cell->value;

      if ( m->name == selector )
	return m;
    }
  } else
  { if ( cdecls )
    { if ( code == NAME_send )
      { const senddecl *sm;

	for( i = cdecls->nsend, sm = cdecls->send_methods; i-- > 0; sm++ )
	{ if ( sm->name == selector )
	    return attachLazySendMethodClass(class, sm);
	}
      } else				/* get */
      { const getdecl *gm;

	for( i = cdecls->nget, gm = cdecls->get_methods; i-- > 0; gm++ )
	{ if ( gm->name == selector )
	    return attachLazyGetMethodClass(class, gm);
	}
      }
    }
  }

  fail;
}


Any
getResolveSendMethodClass(Class class, Name name)
{ Cell cell;
  Class super;

  realiseClass(class);

  for(super = class; notNil(super); super = super->super_class)
  { Any sm;

    if ( (sm = getMemberHashTable(super->send_table, name)) )
    { if ( class != super )
	appendHashTable(class->send_table, name, sm);
      answer(sm);
    }

					/* first do built-in, so redefines */
					/* need to remove a method first */
    for_cell(cell, super->send_methods)
    { SendMethod m = cell->value;

      if ( m->name == name )
      { appendHashTable(class->send_table, name, m);
	answer(m);
      }
    }

    if ( onDFlag(super, DC_LAZY_SEND) )
    { if ( (sm = bindMethod(super, NAME_send, name)) )
      {	appendHashTable(class->send_table, name, sm);
	answer(sm);
      }
    }

    for_vector(super->instance_variables, Variable var,
	       { if ( var->name == name &&
		      sendAccessVariable(var) &&
		      var->context == super )
		 { appendHashTable(class->send_table, name, var);
		   answer(var);
		 }
	       });
  }

  appendHashTable(class->send_table, name, NIL);
  fail;
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Find the implementation for get-behaviour defined on a class. This isn't
very critical, as it is shielded  by getGetMethodClass(), which performs
caching.

Class-variables  are  a  nuisance,  as   it    is   defined  that  other
get-implementation always precedes class-variables, even   if  the other
behaviour is defined higher in the hierarchy.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

Any
getResolveGetMethodClass(Class class, Name name)
{ Class super;
  ClassVariable cv = NULL;

  realiseClass(class);

  for(super = class; notNil(super); super = super->super_class)
  { Any gm;
    Cell cell;

    if ( (gm = getMemberHashTable(super->get_table, name)) )
    { if ( cv && instanceOfObject(gm, ClassClassVariable) )
	gm = cv;
      if ( class != super )
	appendHashTable(class->get_table, name, gm);
      answer(gm);
    }

    for_cell(cell, super->get_methods)
    { GetMethod m = cell->value;

      if ( m->name == name )
      { appendHashTable(class->get_table, name, m);
	answer(m);
      }
    }

    if ( onDFlag(super, DC_LAZY_GET) )
    { if ( (gm = bindMethod(super, NAME_get, name)) )
      { appendHashTable(class->get_table, name, gm);
	answer(gm);
      }
    }

    for_vector(super->instance_variables, Variable var,
	       { if ( var->name == name &&
		      getAccessVariable(var) &&
		      var->context == super )
		 { appendHashTable(class->get_table, name, var);
		   answer(var);
		 }
	       });

    if ( !cv )
    { for_cell(cell, super->class_variables)
      { ClassVariable v = cell->value;

	if ( v->name == name )
	{ cv = v;
	  break;
	}
      }
    }
  }

  if ( cv )
  { appendHashTable(class->get_table, name, cv);
    answer(cv);
  }

  appendHashTable(class->get_table, name, NIL);
  fail;
}


static status
clearCacheClass(Class class)
{ if ( class->realised == ON )
  { clearHashTable(class->send_table);
    clearHashTable(class->get_table);

    assign(class, initialise_method, DEFAULT);
    assign(class, lookup_method,     DEFAULT);

    setDFlag(class, DC_LAZY_SEND|DC_LAZY_GET);

    installClass(class);		/* Enter function special methods */
  }

  succeed;
}


static status
deleteSendMethodClass(Class class, Name selector)
{ if ( class->realised == ON )
  { Cell cell;

    deleteHashTable(class->send_table, selector);
    for_cell(cell, class->send_methods)
    { SendMethod sm = cell->value;

      if ( sm->name == selector )
      { deleteChain(class->send_methods, sm);
	break;
      }
    }

    if ( selector == NAME_initialise )
      assign(class, initialise_method, DEFAULT);
    else if ( selector == NAME_catchAll )
      assign(class, send_catch_all, DEFAULT);
  }

  succeed;
}


static status
deleteGetMethodClass(Class class, Name selector)
{ if ( class->realised == ON )
  { Cell cell;

    deleteHashTable(class->get_table, selector);
    for_cell(cell, class->get_methods)
    { GetMethod sm = cell->value;

      if ( sm->name == selector )
      { deleteChain(class->get_methods, sm);
	break;
      }
    }

    if ( selector == NAME_lookup )
      assign(class, lookup_method, DEFAULT);
    else if ( selector == NAME_convert )
      assign(class, convert_method, DEFAULT);
  }

  succeed;
}


Int
getNoCreatedClass(Class class, BoolObj subtoo)
{ Cell cell;
  Int rval = class->no_created;

  if ( notNil(class->sub_classes) && subtoo == ON )
    for_cell(cell, class->sub_classes)
      rval = add(rval, getNoCreatedClass(cell->value, subtoo));

  answer(rval);
}


Int
getNoFreedClass(Class class, BoolObj subtoo)
{ Cell cell;
  Int rval = class->no_freed;

  if ( notNil(class->sub_classes) && subtoo == ON )
    for_cell(cell, class->sub_classes)
      rval = add(rval, getNoFreedClass(cell->value, subtoo));

  answer(rval);
}


/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
			  KEEP TRACK OF INSTANCES
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

status
createdClass(Class class, Any instance, Name how)
{ incrInt(class->no_created);
  clearCreatingObj(instance);

  if ( notNil(class->created_messages) )
  { Cell cell;

    addCodeReference(instance);		/* avoid drop-out */
    for_cell(cell, class->created_messages)
      forwardCode(cell->value, class->name, instance, how, EAV);
    delCodeReference(instance);
  }

  if ( notNil(class->instances) )
    appendHashTable(class->instances, instance, ON);

  succeed;
}


status
freedClass(Class class, Any instance)
{ clearFlag(instance, F_INSPECT);

  incrInt(class->no_freed);
  if ( notNil(class->freed_messages) )
  { Cell cell;

    addCodeReference(instance);		/* avoid looping */
    for_cell(cell, class->freed_messages)
      forwardCode(cell->value, class->name, instance, EAV);
    if ( !isFreedObj(instance) )
      delCodeReference(instance);
  }

  if ( notNil(class->instances) )
    deleteHashTable(class->instances, instance);

  succeed;
}


static status
recordInstancesClass(Class class, BoolObj keep, BoolObj recursive)
{ realiseClass(class);

  if ( keep != OFF && isNil(class->instances) )
    assign(class, instances, createHashTable(toInt(16), NAME_none));
  else if ( keep == OFF && notNil(class->instances) )
    assign(class, instances, NIL);

  if ( recursive != OFF && notNil(class->sub_classes) )
  { Cell cell;

    for_cell(cell, class->sub_classes)
      recordInstancesClass(cell->value, keep, recursive);
  }

  succeed;
}


static status
changedMessageClass(Class class, Code msg)
{ realiseClass(class);

  if ( isNil(class->changed_messages) )
  { assign(class, changed_messages, newObject(ClassChain, msg, EAV));
    succeed;
  }

  return addChain(class->changed_messages, msg);
}


static status
createdMessageClass(Class class, Code msg)
{ realiseClass(class);

  if ( isNil(class->created_messages) )
  { assign(class, created_messages, newObject(ClassChain, msg, EAV));
    succeed;
  }

  return addChain(class->created_messages, msg);
}


static status
freedMessageClass(Class class, Code msg)
{ realiseClass(class);

  if ( isNil(class->freed_messages) )
  { assign(class, freed_messages, newObject(ClassChain, msg, EAV));
    succeed;
  }

  return addChain(class->freed_messages, msg);
}


static Name
getSuperClassNameClass(Class cl)
{ if ( notNil(cl->super_class) )
    answer(cl->super_class->name);

  fail;
}

#ifndef O_RUNTIME

		/********************************
		*        MANUAL SUPPORT		*
		********************************/

static Name
getManIdClass(Class class)
{ static Name cdot = NULL;

  if ( !cdot )
    cdot = CtoName("C.");

  answer(getAppendName(cdot, class->name));
}


static Name
getManIndicatorClass(Class class)
{ answer(CtoName("C"));
}


static status
append_class_header(Class cl, TextBuffer tb)
{ appendTextBuffer(tb, (CharArray)cl->name, ONE);
  CAppendTextBuffer(tb, "(");

  if ( isNil(cl->term_names) )
  { CAppendTextBuffer(tb, "...object...");
  } else
  { int i;

    for(i=1; i<=valInt(cl->term_names->size); i++)
    { if ( i != 1 )
	CAppendTextBuffer(tb, ", ");
      appendTextBuffer(tb, getElementVector(cl->term_names, toInt(i)), ONE);
    }
  }
  CAppendTextBuffer(tb, ")");

  succeed;
}


static StringObj
getManHeaderClass(Class cl)
{ TextBuffer tb;
  StringObj str;

  realiseClass(cl);

  tb = newObject(ClassTextBuffer, EAV);
  tb->undo_buffer_size = ZERO;

  append_class_header(cl, tb);

  str = getContentsTextBuffer(tb, ZERO, DEFAULT);
  doneObject(tb);

  answer(str);
}


static StringObj
getManSummaryClass(Class cl)
{ TextBuffer tb;
  StringObj str;

  realiseClass(cl);

  tb = newObject(ClassTextBuffer, EAV);
  tb->undo_buffer_size = ZERO;

  CAppendTextBuffer(tb, "C\t");
  append_class_header(cl, tb);

  if ( notNil(cl->summary) )
  { CAppendTextBuffer(tb, "\t");
    appendTextBuffer(tb, (CharArray)cl->summary, ONE);
  }
  if ( send(cl, NAME_hasHelp, EAV) )
    CAppendTextBuffer(tb, " (+)");

  str = getContentsTextBuffer(tb, ZERO, DEFAULT);
  doneObject(tb);

  answer(str);
}
#endif /*O_RUNTIME*/


status
isAClass(Class class, Class super)
{ return class->tree_index >= super->tree_index &&
         class->tree_index <  super->neighbour_index;
}


int
numberTreeClass(Class class, int n)
{ Cell cell;

  DEBUG(NAME_class, Cprintf("numberTreeClass(%s, %d)\n", pp(class->name), n));
  class->tree_index = n++;
  if ( notNil(class->sub_classes) )
  { for_cell(cell, class->sub_classes	)
    { if ( instanceOfObject(cell->value, ClassClass) ) /* stubs ... */
	n = numberTreeClass(cell->value, n);
    }
  }
  class->neighbour_index = n;

  return n;
}


		 /*******************************
		 *	     FEATURE ITF	*
		 *******************************/

status
featureClass(Class class, Name name, Any value)
{ realiseClass(class);

  if ( isDefault(value) )
    value = ON;

  if ( isNil(class->features) )
    assign(class, features, newObject(ClassSheet, EAV));

  return valueSheet(class->features, name, value);
}


static status
hasFeatureClass(Class class, Name name, Any value)
{ realiseClass(class);

  if ( notNil(class->features) )
  { Any fval;
    if ( (fval = getValueSheet(class->features, name)) &&
	 (isDefault(value) || value == fval) )
      succeed;
  }

  fail;
}


Any
getFeatureClass(Class class, Name name)
{ realiseClass(class);

  if ( notNil(class->features) )
    return getValueSheet(class->features, name);

  fail;
}


		 /*******************************
		 *	LAZY METHOD BINDING	*
		 *******************************/

static BoolObj
getLazyBindingClass(Class class, Name which)
{ unsigned long mask = (which == NAME_send ? DC_LAZY_SEND : DC_LAZY_GET);

  answer(onDFlag(class, mask) ? ON : OFF);
}


static status
lazyBindingClass(Class class, Name which, BoolObj val)
{ unsigned long mask = (which == NAME_send ? DC_LAZY_SEND : DC_LAZY_GET);

  DEBUG(NAME_lazyBinding,
	Cprintf("lazyBindingClass(%s, %s, %s)\n",
		pp(class), pp(which), pp(val)));

  if ( val == ON )
    setDFlag(class, mask);
  else
  { if ( onDFlag(class, mask ) )
    { bindMethod(class, which, DEFAULT);
      clearDFlag(class, mask);
    }
  }

  succeed;
}


Chain
getSendMethodsClass(Class class)
{ realiseClass(class);
  lazyBindingClass(class, NAME_send, OFF);

  answer(class->send_methods);
}


static Chain
getGetMethodsClass(Class class)
{ realiseClass(class);
  lazyBindingClass(class, NAME_get, OFF);

  answer(class->get_methods);
}


static Chain
getSubClassesClass(Class class)
{ if ( notNil(class->sub_classes) )
    answer(class->sub_classes);

  fail;
}



status
makeClassClass(Class class)
{ sourceClass(class, makeClassClass, __FILE__, "$Revision$");

  localClass(class, NAME_name, NAME_name, "name", NAME_get,
	     "Name of the class");
  localClass(class, NAME_summary, NAME_manual, "string*", NAME_both,
	     "Summary documentation for class");
  localClass(class, NAME_creator, NAME_manual, "{built_in,host,C++}", NAME_get,
	     "Who created the class");
  localClass(class, NAME_superClass, NAME_type, "class*", NAME_get,
	     "Immediate super class");
  localClass(class, NAME_subClasses, NAME_type, "chain*", NAME_none,
	     "Sub classes");
  localClass(class, NAME_instanceVariables, NAME_behaviour, "vector", NAME_get,
	     "Vector object holding all instance variables");
  localClass(class, NAME_sendMethods, NAME_behaviour, "chain", NAME_none,
	     "Send methods not inherited");
  localClass(class, NAME_getMethods, NAME_behaviour, "chain", NAME_none,
	     "Get methods not inherited");
  localClass(class, NAME_termNames, NAME_term, "vector*", NAME_both,
	     "Selectors to obtain term arguments");
  localClass(class, NAME_delegate, NAME_behaviour, "chain", NAME_get,
	     "Instance variables for delegation");
  localClass(class, NAME_classVariables, NAME_default, "chain", NAME_get,
	     "User setable class-variables");
  localClass(class, NAME_cloneStyle, NAME_copy,
	     "{recursive,none,relation}", NAME_both,
	     "How to clone instances");
  localClass(class, NAME_saveStyle, NAME_file,
	     "{normal,external,nil}",NAME_both,
	     "How to save instances to file");
  localClass(class, NAME_features, NAME_version, "sheet*", NAME_none,
	     "Defined features on this class");
  localClass(class, NAME_noCreated, NAME_statistics, "int", NAME_none,
	     "Number of instances created");
  localClass(class, NAME_noFreed, NAME_statistics, "int", NAME_none,
	     "Number of instances freed");
  localClass(class, NAME_solid, NAME_repaint, "bool", NAME_none,
	     "Graphicals: image affects ALL pixels");
  localClass(class, NAME_selectionStyle, NAME_selection,
	     "{none,invert,corner_handles,side_handles,corner_and_side_handles,line_handles,path_handles}*",
	     NAME_both,
	     "Graphicals: visual feedback of selected");
  localClass(class, NAME_handles, NAME_relation, "chain*", NAME_both,
	     "Graphicals: connection points for links");
  localClass(class, NAME_instanceSize, NAME_oms, "int", NAME_get,
	     "Size of an instance in bytes");
  localClass(class, NAME_slots, NAME_oms, "int", NAME_get,
	     "Total number of instance variables");
  localClass(class, NAME_source, NAME_manual, "source_location*", NAME_both,
	     "Location in the sources");
  localClass(class, NAME_rcsRevision, NAME_version, "name*", NAME_get,
	     "RCS revision of sourcefile");
  localClass(class, NAME_changedMessages, NAME_change, "chain*", NAME_both,
	     "Report (forward) changes to instances");
  localClass(class, NAME_createdMessages, NAME_change, "chain*", NAME_both,
	     "Report (forward) created instances");
  localClass(class, NAME_freedMessages, NAME_change, "chain*", NAME_both,
	     "Report (forward) freed instances");
  localClass(class, NAME_unAnswer, NAME_oms, "bool", NAME_both,
	     "Incremental garbage collection hint");

  localClass(class, NAME_makeClassMethod, NAME_realise, "code*", NAME_get,
	     "Code object to ->realise the class");

  localClass(class, NAME_initialiseMethod, NAME_cache, "[send_method]",
	     NAME_none,
	     "Used to initialise a new instance");
  localClass(class, NAME_sendCatchAll, NAME_cache, "[send_method]*", NAME_none,
	     "Handle not-yet-handled send messages");
  localClass(class, NAME_getCatchAll, NAME_cache, "[get_method]*", NAME_none,
	     "Handle not-yet-handled get messages");
  localClass(class, NAME_convertMethod, NAME_cache, "[get_method]*", NAME_none,
	     "Type conversion");
  localClass(class, NAME_lookupMethod, NAME_cache, "[get_method]*", NAME_none,
	     "Type conversion");

  localClass(class, NAME_resolveMethodMessage, NAME_cache,
	     "[code|c_pointer]*",NAME_both,
	     "Hook for lazy attachment of methods");

  localClass(class, NAME_sendTable, NAME_cache, "hash_table", NAME_get,
	     "Hash table for all send methods");
  localClass(class, NAME_getTable, NAME_cache, "hash_table", NAME_get,
	     "Hash table for all get methods");
  localClass(class, NAME_localTable, NAME_cache, "hash_table", NAME_get,
	     "Hash table for all instance variables");
  localClass(class, NAME_classVariableTable, NAME_cache, "hash_table*",
	     NAME_get,
	     "Hash table for all class-variables");

  localClass(class, NAME_instances, NAME_debugging, "hash_table*", NAME_get,
	     "Hash table holding existing instances");
  localClass(class, NAME_realised, NAME_realise, "bool", NAME_get,
	     "@on if class is realised");
  localClass(class, NAME_initVariables, NAME_cache, "{static,value,function}", NAME_get,
	     "How variables must be initialised");

  localClass(class, NAME_proto, NAME_cache, "alien:InstanceProto", NAME_none,
	     "Prototype instance + info for fast creation");
  localClass(class, NAME_treeIndex, NAME_cache, "alien:int", NAME_none,
	     "Index in depth-first numbering of hierarchy");
  localClass(class, NAME_neighbourIndex, NAME_cache, "alien:int", NAME_none,
	     "Index of neighbour in hierarchy");
  localClass(class, NAME_getFunction, NAME_internal, "alien:GetFunc", NAME_none,
	     "Execute function-objects");
  localClass(class, NAME_sendFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "Execute code-objects");
  localClass(class, NAME_saveFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "C-function to save alien data");
  localClass(class, NAME_loadFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "C-function to reload alien data");
  localClass(class, NAME_cloneFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "C function to clone alien data");
  localClass(class, NAME_redrawFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "C function to repaint graphicals");
  localClass(class, NAME_changedFunction, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "C function to trap slot changes");
  localClass(class, NAME_inEventArea, NAME_internal,
	     "alien:SendFunc", NAME_none,
	     "Graphicals: test if event in area");
  localClass(class, NAME_makeClassFunction, NAME_internal,
	     "alien:VoidFunc", NAME_none,
	     "C-function that created the class");
  localClass(class, NAME_boot, NAME_internal,
	     "alien:int", NAME_none,
	     "#PCE slots when booting; 0 otherwise");
  localClass(class, NAME_cDeclarations, NAME_internal,
	     "alien:classdecl*", NAME_none,
	     "Description left by C-compiler");

  termClass(class, "class", 2, NAME_name, NAME_superClassName);
  saveStyleClass(class, NAME_external);
  cloneStyleClass(class, NAME_none);

  fetchMethod(class, NAME_sendMethods, getSendMethodsClass);
  fetchMethod(class, NAME_getMethods, getGetMethodsClass);

  sendMethod(class, NAME_initialise, DEFAULT, 2, "name=name", "super=[class]*",
	     "Create from name and super class",
	     initialiseClass);
  sendMethod(class, NAME_unlink, DEFAULT, 0,
	     "Remove from tables",
	     unlinkClass);
  sendMethod(class, NAME_changedMessage, NAME_change, 1, "code",
	     "Add message to trap changed slots",
	     changedMessageClass);
  sendMethod(class, NAME_createdMessage, NAME_change, 1, "code",
	     "Add message to trap created instances",
	     createdMessageClass);
  sendMethod(class, NAME_freedMessage, NAME_change, 1, "code",
	     "Add message to trap freed instances",
	     freedMessageClass);
  sendMethod(class, NAME_recordInstances, NAME_debugging, 2,
	     "record=[bool]", "recursive=[bool]",
	     "Maintain <-instances table",
	     recordInstancesClass);
  sendMethod(class, NAME_sendMethod, NAME_behaviour, 1, "send_method",
	     "Add/redefine send method",
	     sendMethodClass);
  sendMethod(class, NAME_getMethod, NAME_behaviour, 1, "get_method",
	     "Add/redefine get method",
	     getMethodClass);
  sendMethod(class, NAME_instanceVariable, NAME_behaviour, 1, "variable",
	     "Add/redefine instance variable",
	     instanceVariableClass);
  sendMethod(class, NAME_isA, NAME_type, 1, "class",
	     "Test if I'm a subclass of argument",
	     isAClass);
  sendMethod(class, NAME_handle, NAME_relation, 1, "handle",
	     "Add handle for graphical instances",
	     handleClass);
  sendMethod(class, NAME_cloneStyleVariable, NAME_copy, 2,
	     "variable=name|int",
	     "style={recursive,reference,reference_chain,value,alien,nil}",
	     "Set <->clone_style of named variable",
	     cloneStyleVariableClass);
  sendMethod(class, NAME_saveStyleVariable, NAME_file, 2,
	     "variable=name|int", "style={normal,nil}",
	     "Set the save style for named variable",
	     saveStyleVariableClass);
  sendMethod(class, NAME_delegate, NAME_behaviour, 1,
	     "variable=name|int",
	     "Add instance-variable for delegation",
	     delegateClass);
  sendMethod(class, NAME_prependDelegate, NAME_behaviour, 1,
	     "variable=name|int",
	     "Add instance-variable for delegation (as first)",
	     prependDelegateClass);
  sendMethod(class, NAME_realise, NAME_realise, 0,
	     "Declare methods/variables, etc.",
	     realiseClass);
  sendMethod(class, NAME_install, NAME_behaviour, 0,
	     "Prepare class for creating instances",
	     installClass);
  sendMethod(class, NAME_clearCache, NAME_cache, 0,
	     "Clear method resolution cache",
	     clearCacheClass);
  sendMethod(class, NAME_deleteSendMethod, NAME_cache, 1, "name",
	     "Delete a send-method",
	     deleteSendMethodClass);
  sendMethod(class, NAME_deleteGetMethod, NAME_cache, 1, "name",
	     "Delete a get-method",
	     deleteGetMethodClass);
  sendMethod(class, NAME_feature, NAME_version, 2,
	     "feature=name", "value=[any]",
	     "Register class feature",
	     featureClass);
  sendMethod(class, NAME_hasFeature, NAME_version, 2,
	     "feature=name", "value=[any]",
	     "Test if class has feature",
	     hasFeatureClass);
#ifdef O_RUNTIME
  sendMethod(class, NAME_source, NAME_runtime, 1, "source_location*",
	     "Dummy method",
	     rtSourceClass);
#endif
  sendMethod(class, NAME_boundSendMethod, NAME_cache, 1, "name",
	     "Test if class defines send_method `name'",
	     boundSendMethodClass);
  sendMethod(class, NAME_boundGetMethod, NAME_cache, 1, "name",
	     "Test if class defines get_method `name'",
	     boundGetMethodClass);
  sendMethod(class, NAME_lazyBinding, NAME_cache, 2, "{send,get}", "bool",
	     "Determines when messages are bound",
	     lazyBindingClass);

  getMethod(class, NAME_subClass, NAME_oms, "class", 1, "name",
	    "Create a class below this one (or return existing)",
	    getSubClassClass);
  getMethod(class, NAME_instance, NAME_oms, "object", 1,
	    "argument=unchecked ...",
	    "Create instance of the class from argument",
	    getInstanceClassv);
  getMethod(class, NAME_instanceVariable, NAME_meta, "variable", 1, "name|int",
	    "Get instance variable from name of offset",
	    getInstanceVariableClass);
#ifndef O_RUNTIME
  getMethod(class, NAME_manId, NAME_manual, "name", 0,
	    "Identifier for the manual (C.<name>)",
	    getManIdClass),
  getMethod(class, NAME_manIndicator, NAME_manual, "name", 0,
	    "Indicator for the manual (C)",
	    getManIndicatorClass),
  getMethod(class, NAME_manHeader, NAME_manual, "string", 0,
	    "New string with with term description",
	    getManHeaderClass);
  getMethod(class, NAME_manSummary, NAME_manual, "string", 0,
	    "New string with header and summary",
	    getManSummaryClass);
#endif
  getMethod(class, NAME_getMethod, NAME_meta, "behaviour", 1, "name",
	    "Method implementing named get behaviour",
	    getGetMethodClass);
  getMethod(class, NAME_sendMethod, NAME_meta, "behaviour", 1, "name",
	    "Method implementing named get behaviour",
	    getSendMethodClass);
  getMethod(class, NAME_superClassName, NAME_type, "name", 0,
	    "Name of super-class or @nil (term description",
	    getSuperClassNameClass);
  getMethod(class, NAME_subClasses, NAME_type, "chain", 0,
	    "Chain holding sub-classes of this class",
	    getSubClassesClass);
  getMethod(class, NAME_convert, DEFAULT, "class", 1, "any",
	    "Convert class name",
	    getConvertClass);
  getMethod(class, NAME_lookup, NAME_oms, "class", 2,
	    "name=name", "super=[class]",
	    "Lookup in @classes and verify super",
	    getLookupClass);
  getMethod(class, NAME_feature, NAME_version, "any", 1, "feature=name",
	    "Get value of given feature",
	    getFeatureClass);
  getMethod(class, NAME_lazyBinding, NAME_cache, "bool", 1, "{send,get}",
	    "@on if methods are bound lazy",
	    getLazyBindingClass);
  getMethod(class, NAME_noCreated, NAME_statistics, "int", 1, "sub_too=[bool]",
	    "How many instances were created",
	    getNoCreatedClass);
  getMethod(class, NAME_noFreed, NAME_statistics, "int", 1, "sub_too=[bool]",
	    "How many instances were freed",
	    getNoFreedClass);


		 /*******************************
		 *	   RESOURCE FUNCTIONS	*
		 *******************************/

  sendMethod(class, NAME_classVariableValue, NAME_default, 2, "name", "any",
	     "Set value of named class variable",
	     classVariableValueClass);
  getMethod(class, NAME_classVariable, NAME_default,
	    "class_variable", 1, "name",
	    "Associated class variable from name",
	    getClassVariableClass);

  succeed;
}

