X-Git-Url: http://deadsoftware.ru/gitweb?a=blobdiff_plain;f=oberon.c;h=e12ee36174e9fd9cfd9a870225dea8528d46e8f8;hb=c15b86365824545bdee7d813ce0c796f1bdff592;hp=7ca600e205a26e377f25bea0de64ff7ad0c758cf;hpb=8520fd72cf3c1daeabbb8da91290dae85fc39c91;p=dsw-obn.git

diff --git a/oberon.c b/oberon.c
index 7ca600e..e12ee36 100644
--- a/oberon.c
+++ b/oberon.c
@@ -50,7 +50,10 @@ enum {
 	RBRACE,
 	RECORD,
 	POINTER,
-	TO
+	TO,
+	UPARROW,
+	NIL,
+	IMPORT
 };
 
 // =======================================================================
@@ -106,16 +109,19 @@ oberon_new_type_boolean(int size)
 static oberon_scope_t *
 oberon_open_scope(oberon_context_t * ctx)
 {
-	oberon_scope_t * scope = malloc(sizeof *scope);
-	memset(scope, 0, sizeof *scope);
-
-	oberon_object_t * list = malloc(sizeof *list);
-	memset(list, 0, sizeof *list);
+	oberon_scope_t * scope = calloc(1, sizeof *scope);
+	oberon_object_t * list = calloc(1, sizeof *list);
 
 	scope -> ctx = ctx;
 	scope -> list = list;
 	scope -> up = ctx -> decl;
 
+	if(scope -> up)
+	{
+		scope -> parent = scope -> up -> parent;
+		scope -> local = scope -> up -> local;
+	}
+
 	ctx -> decl = scope;
 	return scope;
 }
@@ -145,6 +151,8 @@ oberon_define_object(oberon_scope_t * scope, char * name, int class)
 	memset(newvar, 0, sizeof *newvar);
 	newvar -> name = name;
 	newvar -> class = class;
+	newvar -> local = scope -> local;
+	newvar -> parent = scope -> parent;
 
 	x -> next = newvar;
 
@@ -154,6 +162,8 @@ oberon_define_object(oberon_scope_t * scope, char * name, int class)
 static void
 oberon_define_field(oberon_context_t * ctx, oberon_type_t * rec, char *  name, oberon_type_t * type)
 {
+	// TODO check base fields
+
 	oberon_object_t * x = rec -> decl;
 	while(x -> next && strcmp(x -> next -> name, name) != 0)
 	{
@@ -170,10 +180,10 @@ oberon_define_field(oberon_context_t * ctx, oberon_type_t * rec, char *  name, o
 	field -> name = name;
 	field -> class = OBERON_CLASS_FIELD;
 	field -> type = type;
+	field -> local = 1;
+	field -> parent = NULL;
 
 	rec -> num_decl += 1;
-	oberon_generator_init_var(ctx, field);
-
 	x -> next = field;
 }
 
@@ -189,7 +199,7 @@ oberon_find_object_in_list(oberon_object_t * list, char * name)
 }
 
 static oberon_object_t *
-oberon_find_object(oberon_scope_t * scope, char * name)
+oberon_find_object(oberon_scope_t * scope, char * name, int check_it)
 {
 	oberon_object_t * result = NULL;
 
@@ -200,7 +210,7 @@ oberon_find_object(oberon_scope_t * scope, char * name)
 		s = s -> up;
 	}
 
-	if(result == NULL)
+	if(check_it && result == NULL)
 	{
 		oberon_error(scope -> ctx, "undefined ident %s", name);
 	}
@@ -236,6 +246,7 @@ oberon_define_type(oberon_scope_t * scope, char * name, oberon_type_t * type)
 	return id;
 }
 
+/*
 static oberon_type_t *
 oberon_find_type(oberon_scope_t * scope, char * name)
 {
@@ -247,6 +258,7 @@ oberon_find_type(oberon_scope_t * scope, char * name)
 
 	return x -> type;
 }
+*/
 
 static oberon_object_t *
 oberon_define_var(oberon_scope_t * scope, int class, char * name, oberon_type_t * type)
@@ -254,7 +266,6 @@ oberon_define_var(oberon_scope_t * scope, int class, char * name, oberon_type_t
 	oberon_object_t * var;
 	var = oberon_define_object(scope, name, class);
 	var -> type = type;
-	oberon_generator_init_var(scope -> ctx, var);
 	return var;
 }
 
@@ -273,15 +284,16 @@ oberon_find_var(oberon_scope_t * scope, char * name)
 }
 */
 
+/*
 static oberon_object_t *
 oberon_define_proc(oberon_scope_t * scope, char * name, oberon_type_t * signature)
 {
 	oberon_object_t * proc;
 	proc = oberon_define_object(scope, name, OBERON_CLASS_PROC);
 	proc -> type = signature;
-	oberon_generator_init_proc(scope -> ctx, proc);
 	return proc;
 }
+*/
 
 // =======================================================================
 //   SCANER
@@ -397,6 +409,14 @@ oberon_read_ident(oberon_context_t * ctx)
 	{
 		ctx -> token = TO;
 	}
+	else if(strcmp(ident, "NIL") == 0)
+	{
+		ctx -> token = NIL;
+	}
+	else if(strcmp(ident, "IMPORT") == 0)
+	{
+		ctx -> token = IMPORT;
+	}
 }
 
 static void
@@ -529,6 +549,10 @@ oberon_read_symbol(oberon_context_t * ctx)
 			ctx -> token = RBRACE;
 			oberon_get_char(ctx);
 			break;
+		case '^':
+			ctx -> token = UPARROW;
+			oberon_get_char(ctx);
+			break;
 		default:
 			oberon_error(ctx, "invalid char");
 			break;
@@ -563,7 +587,8 @@ static void oberon_expect_token(oberon_context_t * ctx, int token);
 static oberon_expr_t * oberon_expr(oberon_context_t * ctx);
 static void oberon_assert_token(oberon_context_t * ctx, int token);
 static char * oberon_assert_ident(oberon_context_t * ctx);
-static oberon_type_t * oberon_type(oberon_context_t * ctx);
+static void oberon_type(oberon_context_t * ctx, oberon_type_t ** type);
+static oberon_item_t * oberon_const_expr(oberon_context_t * ctx);
 
 static oberon_expr_t *
 oberon_new_operator(int op, oberon_type_t * result, oberon_expr_t * left, oberon_expr_t * right)
@@ -630,7 +655,7 @@ oberon_make_unary_op(oberon_context_t * ctx, int token, oberon_expr_t * a)
 }
 
 static void
-oberon_expr_list(oberon_context_t * ctx, int * num_expr, oberon_expr_t ** first)
+oberon_expr_list(oberon_context_t * ctx, int * num_expr, oberon_expr_t ** first, int const_expr)
 {
 	oberon_expr_t * last;
 
@@ -640,7 +665,16 @@ oberon_expr_list(oberon_context_t * ctx, int * num_expr, oberon_expr_t ** first)
 	{
 		oberon_assert_token(ctx, COMMA);
 		oberon_expr_t * current;
-		current = oberon_expr(ctx);
+
+		if(const_expr)
+		{
+			current = (oberon_expr_t *) oberon_const_expr(ctx);
+		}
+		else
+		{
+			current = oberon_expr(ctx);
+		}
+
 		last -> next = current;
 		last = current;
 		*num_expr += 1;
@@ -655,7 +689,6 @@ oberon_autocast_to(oberon_context_t * ctx, oberon_expr_t * expr, oberon_type_t *
 		oberon_error(ctx, "incompatible types");
 	}
 
-
 	if(pref -> class == OBERON_TYPE_INTEGER)
 	{
 		if(expr -> result -> class > pref -> class)
@@ -671,6 +704,16 @@ oberon_autocast_to(oberon_context_t * ctx, oberon_expr_t * expr, oberon_type_t *
 			oberon_error(ctx, "incompatible record types");
 		}
 	}
+	else if(pref -> class == OBERON_TYPE_POINTER)
+	{
+		if(expr -> result -> base != pref -> base)
+		{
+			if(expr -> result -> base -> class != OBERON_TYPE_VOID)
+			{
+				oberon_error(ctx, "incompatible pointer types");
+			}
+		}
+	}
 
 	// TODO cast
 
@@ -690,7 +733,7 @@ oberon_autocast_call(oberon_context_t * ctx, oberon_expr_t * desig)
 		oberon_error(ctx, "expected mode CALL");
 	}
 
-	if(desig -> item.var -> class != OBERON_CLASS_PROC)
+	if(desig -> item.var -> type -> class != OBERON_TYPE_PROCEDURE)
 	{
 		oberon_error(ctx, "only procedures can be called");
 	}
@@ -712,12 +755,132 @@ oberon_autocast_call(oberon_context_t * ctx, oberon_expr_t * desig)
 	oberon_object_t * param = fn -> decl;
 	for(int i = 0; i < num_args; i++)
 	{
+		if(param -> class == OBERON_CLASS_VAR_PARAM)
+		{
+			if(arg -> is_item)
+			{
+				switch(arg -> item.mode)
+				{
+					case MODE_VAR:
+					case MODE_INDEX:
+					case MODE_FIELD:
+					// Допустимо разыменование?
+					//case MODE_DEREF:
+						break;
+					default:
+						oberon_error(ctx, "var-parameter accept only variables");
+						break;
+				}
+			}
+		}
 		oberon_autocast_to(ctx, arg, param -> type);
 		arg = arg -> next;
 		param = param -> next;
 	}
 }
 
+static oberon_expr_t *
+oberon_make_call_func(oberon_context_t * ctx, oberon_object_t * proc, int num_args, oberon_expr_t * list_args)
+{
+	switch(proc -> class)
+	{
+		case OBERON_CLASS_PROC:
+			if(proc -> class != OBERON_CLASS_PROC)
+			{
+				oberon_error(ctx, "not a procedure");
+			}
+			break;
+		case OBERON_CLASS_VAR:
+		case OBERON_CLASS_VAR_PARAM:
+		case OBERON_CLASS_PARAM:
+			if(proc -> type -> class != OBERON_TYPE_PROCEDURE)
+			{
+				oberon_error(ctx, "not a procedure");
+			}
+			break;
+		default:
+			oberon_error(ctx, "not a procedure");
+			break;
+	}
+
+	oberon_expr_t * call;
+
+	if(proc -> sysproc)
+	{
+		if(proc -> genfunc == NULL)
+		{
+			oberon_error(ctx, "not a function-procedure");
+		}
+
+		call = proc -> genfunc(ctx, num_args, list_args);
+	}
+	else
+	{
+		if(proc -> type -> base -> class == OBERON_TYPE_VOID)
+		{
+			oberon_error(ctx, "attempt to call procedure in expression");
+		}
+
+		call = oberon_new_item(MODE_CALL, proc -> type -> base);
+		call -> item.var = proc;
+		call -> item.num_args = num_args;
+		call -> item.args = list_args;
+		oberon_autocast_call(ctx, call);
+	}
+
+	return call;
+}
+
+static void
+oberon_make_call_proc(oberon_context_t * ctx, oberon_object_t * proc, int num_args, oberon_expr_t * list_args)
+{
+	switch(proc -> class)
+	{
+		case OBERON_CLASS_PROC:
+			if(proc -> class != OBERON_CLASS_PROC)
+			{
+				oberon_error(ctx, "not a procedure");
+			}
+			break;
+		case OBERON_CLASS_VAR:
+		case OBERON_CLASS_VAR_PARAM:
+		case OBERON_CLASS_PARAM:
+			if(proc -> type -> class != OBERON_TYPE_PROCEDURE)
+			{
+				oberon_error(ctx, "not a procedure");
+			}
+			break;
+		default:
+			oberon_error(ctx, "not a procedure");
+			break;
+	}
+
+	if(proc -> sysproc)
+	{
+		if(proc -> genproc == NULL)
+		{
+			oberon_error(ctx, "requres non-typed procedure");
+		}
+
+		proc -> genproc(ctx, num_args, list_args);
+	}
+	else
+	{
+		if(proc -> type -> base -> class != OBERON_TYPE_VOID)
+		{
+			oberon_error(ctx, "attempt to call function as non-typed procedure");
+		}
+
+		oberon_expr_t * call;
+		call = oberon_new_item(MODE_CALL, proc -> type -> base);
+		call -> item.var = proc;
+		call -> item.num_args = num_args;
+		call -> item.args = list_args;
+		oberon_autocast_call(ctx, call);
+		oberon_generate_call_proc(ctx, call);
+	}
+}
+
 #define ISEXPR(x) \
 	(((x) == PLUS) \
 	|| ((x) == MINUS) \
@@ -728,51 +891,65 @@ oberon_autocast_call(oberon_context_t * ctx, oberon_expr_t * desig)
 	|| ((x) == TRUE) \
 	|| ((x) == FALSE))
 
-#define ISSELECTOR(x) \
-	(((x) == LBRACE) \
-	|| ((x) == DOT))
-
 static oberon_expr_t *
-oberon_make_array_selector(oberon_context_t * ctx, oberon_expr_t * desig, int num_indexes, oberon_expr_t * indexes)
+oberno_make_dereferencing(oberon_context_t * ctx, oberon_expr_t * expr)
 {
-	assert(desig -> is_item == 1);
-
-	if(desig -> item.mode != MODE_VAR)
+	if(expr -> result -> class != OBERON_TYPE_POINTER)
 	{
-		oberon_error(ctx, "not MODE_VAR");
+		oberon_error(ctx, "not a pointer");
 	}
 
-	int class = desig -> item.var -> class;
-	switch(class)
+	assert(expr -> is_item);
+
+	oberon_expr_t * selector;
+	selector = oberon_new_item(MODE_DEREF, expr -> result -> base);
+	selector -> item.parent = (oberon_item_t *) expr;
+
+	return selector;
+}
+
+static oberon_expr_t *
+oberon_make_array_selector(oberon_context_t * ctx, oberon_expr_t * desig, oberon_expr_t * index)
+{
+	if(desig -> result -> class == OBERON_TYPE_POINTER)
 	{
-		case OBERON_CLASS_VAR:
-		case OBERON_CLASS_VAR_PARAM:
-		case OBERON_CLASS_PARAM:
-			break;
-		default:
-			oberon_error(ctx, "not variable");
-			break;
+		desig = oberno_make_dereferencing(ctx, desig);
 	}
 
-	oberon_type_t * type = desig -> item.var -> type;
-	if(type -> class != OBERON_TYPE_ARRAY)
+	assert(desig -> is_item);
+
+	if(desig -> result -> class != OBERON_TYPE_ARRAY)
 	{
 		oberon_error(ctx, "not array");
 	}
 
-	int dim = desig -> item.var -> type -> dim;
-	if(num_indexes != dim)
+	oberon_type_t * base;
+	base = desig -> result -> base;
+
+	if(index -> result -> class != OBERON_TYPE_INTEGER)
 	{
-		oberon_error(ctx, "dimesions not matched");
+		oberon_error(ctx, "index must be integer");
 	}
 
-	oberon_type_t * base = desig -> item.var -> type -> base;
+	// Статическая проверка границ массива
+	if(index -> is_item)
+	{
+		if(index -> item.mode == MODE_INTEGER)
+		{
+			int arr_size = desig -> result -> size;
+			int index_int = index -> item.integer;
+			if(index_int < 0 || index_int > arr_size - 1)
+			{
+				oberon_error(ctx, "not in range (dimension size 0..%i)", arr_size - 1);
+			}
+		}
+	}
 
 	oberon_expr_t * selector;
 	selector = oberon_new_item(MODE_INDEX, base);
 	selector -> item.parent = (oberon_item_t *) desig;
-	selector -> item.num_args = num_indexes;
-	selector -> item.args = indexes;
+	selector -> item.num_args = 1;
+	selector -> item.args = index;
 
 	return selector;
 }
@@ -780,10 +957,14 @@ oberon_make_array_selector(oberon_context_t * ctx, oberon_expr_t * desig, int nu
 static oberon_expr_t *
 oberon_make_record_selector(oberon_context_t * ctx, oberon_expr_t * expr, char * name)
 {
+	if(expr -> result -> class == OBERON_TYPE_POINTER)
+	{
+		expr = oberno_make_dereferencing(ctx, expr);
+	}
+
 	assert(expr -> is_item == 1);
 
-	int class = expr -> result -> class;
-	if(class != OBERON_TYPE_RECORD)
+	if(expr -> result -> class != OBERON_TYPE_RECORD)
 	{
 		oberon_error(ctx, "not record");
 	}
@@ -801,6 +982,39 @@ oberon_make_record_selector(oberon_context_t * ctx, oberon_expr_t * expr, char *
 	return selector;
 }
 
+#define ISSELECTOR(x) \
+	(((x) == LBRACE) \
+	|| ((x) == DOT) \
+	|| ((x) == UPARROW))
+
+static oberon_object_t *
+oberon_qualident(oberon_context_t * ctx, char ** xname, int check)
+{
+	char * name;
+	oberon_object_t * x;
+
+	name = oberon_assert_ident(ctx);
+	x = oberon_find_object(ctx -> decl, name, check);
+
+	if(x != NULL)
+	{
+		if(x -> class == OBERON_CLASS_MODULE)
+		{
+			oberon_assert_token(ctx, DOT);
+			name = oberon_assert_ident(ctx);
+			/* Наличие объектов в левых модулях всегда проверяется */
+			x = oberon_find_object(x -> module -> decl, name, 1);
+		}
+	}
+
+	if(xname)
+	{
+		*xname = name;
+	}
+
+	return x;
+}
+
 static oberon_expr_t *
 oberon_designator(oberon_context_t * ctx)
 {
@@ -808,8 +1022,7 @@ oberon_designator(oberon_context_t * ctx)
 	oberon_object_t * var;
 	oberon_expr_t * expr;
 
-	name = oberon_assert_ident(ctx);
-	var = oberon_find_object(ctx -> decl, name);
+	var = oberon_qualident(ctx, NULL, 1);
 
 	switch(var -> class)
 	{
@@ -820,10 +1033,8 @@ oberon_designator(oberon_context_t * ctx)
 		case OBERON_CLASS_VAR:
 		case OBERON_CLASS_VAR_PARAM:
 		case OBERON_CLASS_PARAM:
-			expr = oberon_new_item(MODE_VAR, var -> type);
-			break;
 		case OBERON_CLASS_PROC:
-			expr = oberon_new_item(MODE_CALL, var -> type);
+			expr = oberon_new_item(MODE_VAR, var -> type);
 			break;
 		default:
 			oberon_error(ctx, "invalid designator");
@@ -844,9 +1055,18 @@ oberon_designator(oberon_context_t * ctx)
 				oberon_assert_token(ctx, LBRACE);
 				int num_indexes = 0;
 				oberon_expr_t * indexes = NULL;
-				oberon_expr_list(ctx, &num_indexes, &indexes);
+				oberon_expr_list(ctx, &num_indexes, &indexes, 0);
 				oberon_assert_token(ctx, RBRACE);
-				expr = oberon_make_array_selector(ctx, expr, num_indexes, indexes);
+
+				for(int i = 0; i < num_indexes; i++)
+				{
+					expr = oberon_make_array_selector(ctx, expr, indexes);
+					indexes = indexes -> next;
+				}
+				break;
+			case UPARROW:
+				oberon_assert_token(ctx, UPARROW);
+				expr = oberno_make_dereferencing(ctx, expr);
 				break;
 			default:
 				oberon_error(ctx, "oberon_designator: wat");
@@ -857,17 +1077,13 @@ oberon_designator(oberon_context_t * ctx)
 }
 
 static oberon_expr_t *
-oberon_opt_proc_parens(oberon_context_t * ctx, oberon_expr_t * expr)
+oberon_opt_func_parens(oberon_context_t * ctx, oberon_expr_t * expr)
 {
 	assert(expr -> is_item == 1);
 
+	/* Если есть скобки - значит вызов. Если нет, то передаём указатель. */
 	if(ctx -> token == LPAREN)
 	{
-		if(expr -> result -> class != OBERON_TYPE_PROCEDURE)
-		{
-			oberon_error(ctx, "not a procedure");
-		}
-
 		oberon_assert_token(ctx, LPAREN);
 
 		int num_args = 0;
@@ -875,21 +1091,41 @@ oberon_opt_proc_parens(oberon_context_t * ctx, oberon_expr_t * expr)
 
 		if(ISEXPR(ctx -> token))
 		{
-			oberon_expr_list(ctx, &num_args, &arguments);
+			oberon_expr_list(ctx, &num_args, &arguments, 0);
 		}
 
-		expr -> result = expr -> item.var -> type -> base;
-		expr -> item.mode = MODE_CALL;
-		expr -> item.num_args = num_args;
-		expr -> item.args = arguments;
-		oberon_assert_token(ctx, RPAREN);
+		expr = oberon_make_call_func(ctx, expr -> item.var, num_args, arguments);
 
-		oberon_autocast_call(ctx, expr);
+		oberon_assert_token(ctx, RPAREN);
 	}
 
 	return expr;
 }
 
+static void
+oberon_opt_proc_parens(oberon_context_t * ctx, oberon_expr_t * expr)
+{
+	assert(expr -> is_item == 1);
+
+	int num_args = 0;
+	oberon_expr_t * arguments = NULL;
+
+	if(ctx -> token == LPAREN)
+	{
+		oberon_assert_token(ctx, LPAREN);
+
+		if(ISEXPR(ctx -> token))
+		{
+			oberon_expr_list(ctx, &num_args, &arguments, 0);
+		}
+
+		oberon_assert_token(ctx, RPAREN);
+	}
+
+	/* Вызов происходит даже без скобок */
+	oberon_make_call_proc(ctx, expr -> item.var, num_args, arguments);
+}
+
 static oberon_expr_t *
 oberon_factor(oberon_context_t * ctx)
 {
@@ -899,7 +1135,7 @@ oberon_factor(oberon_context_t * ctx)
 	{
 		case IDENT:
 			expr = oberon_designator(ctx);
-			expr = oberon_opt_proc_parens(ctx, expr);
+			expr = oberon_opt_func_parens(ctx, expr);
 			break;
 		case INTEGER:
 			expr = oberon_new_item(MODE_INTEGER, ctx -> int_type);
@@ -926,6 +1162,10 @@ oberon_factor(oberon_context_t * ctx)
 			expr = oberon_factor(ctx);
 			expr = oberon_make_unary_op(ctx, NOT, expr);
 			break;
+		case NIL:
+			oberon_assert_token(ctx, NIL);
+			expr = oberon_new_item(MODE_NIL, ctx -> void_ptr_type);
+			break;
 		default:
 			oberon_error(ctx, "invalid expression");
 	}
@@ -1176,7 +1416,9 @@ oberon_const_expr(oberon_context_t * ctx)
 //   PARSER
 // =======================================================================
 
+static void oberon_decl_seq(oberon_context_t * ctx);
 static void oberon_statement_seq(oberon_context_t * ctx);
+static void oberon_initialize_decl(oberon_context_t * ctx);
 
 static void
 oberon_expect_token(oberon_context_t * ctx, int token)
@@ -1203,344 +1445,780 @@ oberon_assert_ident(oberon_context_t * ctx)
 	return ident;
 }
 
-static oberon_type_t *
-oberon_make_array_type(oberon_context_t * ctx, int dim, oberon_item_t * size, oberon_type_t * base)
+static void
+oberon_var_decl(oberon_context_t * ctx)
 {
-	assert(dim == 1);
-	oberon_type_t * newtype;
-
-	if(size -> mode != MODE_INTEGER)
-	{
-		oberon_error(ctx, "requires integer constant");
-	}
-
-	newtype = oberon_new_type_ptr(OBERON_TYPE_ARRAY);
-	newtype -> dim = dim;
-	newtype -> size = size -> integer;
-	newtype -> base = base;
-	oberon_generator_init_type(ctx, newtype);
+	char * name;
+	oberon_type_t * type;
+	type = oberon_new_type_ptr(OBERON_TYPE_VOID);
 
-	return newtype;
+	name = oberon_assert_ident(ctx);
+	oberon_assert_token(ctx, COLON);
+	oberon_type(ctx, &type);
+	oberon_define_var(ctx -> decl, OBERON_CLASS_VAR, name, type);
 }
 
-static void
-oberon_field_list(oberon_context_t * ctx, oberon_type_t * rec)
+static oberon_object_t *
+oberon_make_param(oberon_context_t * ctx, int token, char * name, oberon_type_t * type)
 {
-	if(ctx -> token == IDENT)
+	oberon_object_t * param;
+
+	if(token == VAR)
 	{
-		char * name;
-		oberon_type_t * type;
-		name = oberon_assert_ident(ctx);
-		oberon_assert_token(ctx, COLON);
-		type = oberon_type(ctx);
-		oberon_define_field(ctx, rec, name, type);
+		param = oberon_define_var(ctx -> decl, OBERON_CLASS_VAR_PARAM, name, type);
+	}
+	else if(token == IDENT)
+	{
+		param = oberon_define_var(ctx -> decl, OBERON_CLASS_PARAM, name, type);
+	}
+	else
+	{
+		oberon_error(ctx, "oberon_make_param: wat");
 	}
+
+	return param;
 }
 
-static oberon_type_t *
-oberon_make_pointer(oberon_context_t * ctx, oberon_type_t * type)
+static oberon_object_t *
+oberon_fp_section(oberon_context_t * ctx, int * num_decl)
 {
-	if(type -> class == OBERON_TYPE_POINTER)
+	int modifer_token = ctx -> token;
+	if(ctx -> token == VAR)
 	{
-		return type;
+		oberon_read_token(ctx);
 	}
 
-	if(type -> class == OBERON_TYPE_INTEGER
-		|| type -> class == OBERON_TYPE_BOOLEAN
-		|| type -> class == OBERON_TYPE_PROCEDURE
-		|| type -> class == OBERON_TYPE_VOID)
-	{
-		oberon_error(ctx, "oberon not support pointers to non structure types");
-	}
+	char * name;
+	name = oberon_assert_ident(ctx);
+
+	oberon_assert_token(ctx, COLON);
 
-	oberon_type_t * newtype;
-	newtype = oberon_new_type_ptr(OBERON_TYPE_POINTER);
-	newtype -> base = type;
+	oberon_type_t * type;
+	type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+	oberon_type(ctx, &type);
 
-	oberon_generator_init_type(ctx, newtype);
+	oberon_object_t * first;
+	first = oberon_make_param(ctx, modifer_token, name, type);
 
-	return newtype;
+	*num_decl += 1;
+	return first;
 }
 
-static oberon_type_t * oberon_opt_formal_pars(oberon_context_t * ctx, int class);
+#define ISFPSECTION \
+	((ctx -> token == VAR) || (ctx -> token == IDENT))
 
-static oberon_type_t *
-oberon_type(oberon_context_t * ctx)
+static void
+oberon_formal_pars(oberon_context_t * ctx, oberon_type_t * signature)
 {
-	oberon_type_t * type;
+	oberon_assert_token(ctx, LPAREN);
 
-	if(ctx -> token == IDENT)
+	if(ISFPSECTION)
 	{
-		char * name = oberon_assert_ident(ctx);
-		type = oberon_find_type(ctx -> decl, name);
+		signature -> decl = oberon_fp_section(ctx, &signature -> num_decl);
+		while(ctx -> token == SEMICOLON)
+		{
+			oberon_assert_token(ctx, SEMICOLON);
+			oberon_fp_section(ctx, &signature -> num_decl);
+		}
 	}
-	else if(ctx -> token == ARRAY)
+
+	oberon_assert_token(ctx, RPAREN);
+
+	if(ctx -> token == COLON)
 	{
-		oberon_assert_token(ctx, ARRAY);
-		oberon_item_t * size = oberon_const_expr(ctx);
-		oberon_assert_token(ctx, OF);
-		oberon_type_t * base = oberon_type(ctx);
-		type = oberon_make_array_type(ctx, 1, size, base);
-	}
-	else if(ctx -> token == RECORD)
-	{
-		type = oberon_new_type_ptr(OBERON_TYPE_RECORD);
-		oberon_object_t * list = malloc(sizeof *list);
-	        memset(list, 0, sizeof *list);
-		type -> num_decl = 0;
-		type -> base = NULL;
-		type -> decl = list;
+		oberon_assert_token(ctx, COLON);
 
-		oberon_assert_token(ctx, RECORD);
-		oberon_field_list(ctx, type);
-		while(ctx -> token == SEMICOLON)
+		oberon_object_t * typeobj;
+		typeobj = oberon_qualident(ctx, NULL, 1);
+		if(typeobj -> class != OBERON_CLASS_TYPE)
 		{
-			oberon_assert_token(ctx, SEMICOLON);
-			oberon_field_list(ctx, type);
+			oberon_error(ctx, "function result is not type");
 		}
-		oberon_assert_token(ctx, END);
+		signature -> base = typeobj -> type;
+	}
+}
 
-		type -> decl = type -> decl -> next;
-		oberon_generator_init_type(ctx, type);
+static void
+oberon_opt_formal_pars(oberon_context_t * ctx, oberon_type_t ** type)
+{
+	oberon_type_t * signature;
+	signature = *type;
+	signature -> class = OBERON_TYPE_PROCEDURE;
+	signature -> num_decl = 0;
+	signature -> base = ctx -> void_type;
+	signature -> decl = NULL;
+
+	if(ctx -> token == LPAREN)
+	{
+		oberon_formal_pars(ctx, signature);
 	}
-	else if(ctx -> token == POINTER)
+}
+
+static void
+oberon_compare_signatures(oberon_context_t * ctx, oberon_type_t * a, oberon_type_t * b)
+{
+	if(a -> num_decl != b -> num_decl)
 	{
-		oberon_assert_token(ctx, POINTER);
-		oberon_assert_token(ctx, TO);
-		type = oberon_type(ctx);
-		type = oberon_make_pointer(ctx, type);
+		oberon_error(ctx, "number parameters not matched");
 	}
-	else if(ctx -> token == PROCEDURE)
+
+	int num_param = a -> num_decl;
+	oberon_object_t * param_a = a -> decl;
+	oberon_object_t * param_b = b -> decl;
+	for(int i = 0; i < num_param; i++)
 	{
-		oberon_assert_token(ctx, PROCEDURE);
-		type = oberon_opt_formal_pars(ctx, OBERON_TYPE_PROCEDURE);
+		if(strcmp(param_a -> name, param_b -> name) != 0)
+		{
+			oberon_error(ctx, "param %i name not matched", i + 1);
+		}
+
+		if(param_a -> type != param_b -> type)
+		{
+			oberon_error(ctx, "param %i type not matched", i + 1);
+		}
+
+		param_a = param_a -> next;
+		param_b = param_b -> next;
+	}
+}
+
+static void
+oberon_make_return(oberon_context_t * ctx, oberon_expr_t * expr)
+{
+	oberon_object_t * proc = ctx -> decl -> parent;
+	oberon_type_t * result_type = proc -> type -> base;
+
+	if(result_type -> class == OBERON_TYPE_VOID)
+	{
+		if(expr != NULL)
+		{
+			oberon_error(ctx, "procedure has no result type");
+		}
 	}
 	else
 	{
-		oberon_error(ctx, "invalid type declaration");
+		if(expr == NULL)
+		{
+			oberon_error(ctx, "procedure requires expression on result");
+		}
+
+		oberon_autocast_to(ctx, expr, result_type);
 	}
 
-	return type;
+	proc -> has_return = 1;
+
+	oberon_generate_return(ctx, expr);
 }
 
 static void
-oberon_var_decl(oberon_context_t * ctx)
+oberon_proc_decl_body(oberon_context_t * ctx, oberon_object_t * proc)
 {
+	oberon_assert_token(ctx, SEMICOLON);
+
+	ctx -> decl = proc -> scope;
+
+	oberon_decl_seq(ctx);
+
+	oberon_generate_begin_proc(ctx, proc);
+
+	if(ctx -> token == BEGIN)
+	{
+		oberon_assert_token(ctx, BEGIN);
+		oberon_statement_seq(ctx);
+	}
+
+	oberon_assert_token(ctx, END);
 	char * name = oberon_assert_ident(ctx);
-	oberon_assert_token(ctx, COLON);
-	oberon_type_t * type = oberon_type(ctx);
-	oberon_define_var(ctx -> decl, OBERON_CLASS_VAR, name, type);
+	if(strcmp(name, proc -> name) != 0)
+	{
+		oberon_error(ctx, "procedure name not matched");
+	}
+
+	if(proc -> type -> base -> class == OBERON_TYPE_VOID
+		&& proc -> has_return == 0)
+	{
+		oberon_make_return(ctx, NULL);
+	}
+
+	if(proc -> has_return == 0)
+	{
+		oberon_error(ctx, "procedure requires return");
+	}
+
+	oberon_generate_end_proc(ctx);
+	oberon_close_scope(ctx -> decl);
 }
 
-static oberon_object_t *
-oberon_make_param(oberon_context_t * ctx, int token, char * name, oberon_type_t * type)
+static void
+oberon_proc_decl(oberon_context_t * ctx)
 {
-	oberon_object_t * param;
+	oberon_assert_token(ctx, PROCEDURE);
 
-	if(token == VAR)
+	int forward = 0;
+	if(ctx -> token == UPARROW)
 	{
-		param = oberon_define_var(ctx -> decl, OBERON_CLASS_VAR_PARAM, name, type);
+		oberon_assert_token(ctx, UPARROW);
+		forward = 1;
 	}
-	else if(token == IDENT)
+
+	char * name;
+	name = oberon_assert_ident(ctx);
+
+	oberon_scope_t * proc_scope;
+	proc_scope = oberon_open_scope(ctx);
+	ctx -> decl -> local = 1;
+
+	oberon_type_t * signature;
+	signature = oberon_new_type_ptr(OBERON_TYPE_VOID);
+	oberon_opt_formal_pars(ctx, &signature);	
+
+	oberon_initialize_decl(ctx);
+	oberon_generator_init_type(ctx, signature);
+	oberon_close_scope(ctx -> decl);
+
+	oberon_object_t * proc;
+	proc = oberon_find_object(ctx -> decl, name, 0);
+	if(proc != NULL)
 	{
-		param = oberon_define_var(ctx -> decl, OBERON_CLASS_PARAM, name, type);
+		if(proc -> class != OBERON_CLASS_PROC)
+		{
+			oberon_error(ctx, "mult definition");
+		}
+
+		if(forward == 0)
+		{
+			if(proc -> linked)
+			{
+				oberon_error(ctx, "mult procedure definition");
+			}
+		}
+
+		oberon_compare_signatures(ctx, proc -> type, signature);
 	}
 	else
 	{
-		oberon_error(ctx, "oberon_make_param: wat");
+		proc = oberon_define_object(ctx -> decl, name, OBERON_CLASS_PROC);
+		proc -> type = signature;
+		proc -> scope = proc_scope;
+		oberon_generator_init_proc(ctx, proc);
 	}
 
-	return param;
-}
+	proc -> scope -> parent = proc;
 
-static oberon_object_t *
-oberon_fp_section(oberon_context_t * ctx, int * num_decl)
-{
-	int modifer_token = ctx -> token;
-	if(ctx -> token == VAR)
+	if(forward == 0)
 	{
-		oberon_read_token(ctx);
+		proc -> linked = 1;
+		oberon_proc_decl_body(ctx, proc);
 	}
+}
 
+static void
+oberon_const_decl(oberon_context_t * ctx)
+{
 	char * name;
+	oberon_item_t * value;
+	oberon_object_t * constant;
+
 	name = oberon_assert_ident(ctx);
+	oberon_assert_token(ctx, EQUAL);
+	value = oberon_const_expr(ctx);
 
-	oberon_assert_token(ctx, COLON);
+	constant = oberon_define_object(ctx -> decl, name, OBERON_CLASS_CONST);
+	constant -> value = value;
+}
 
-	oberon_type_t * type;
-	type = oberon_type(ctx);
+static void
+oberon_make_array_type(oberon_context_t * ctx, oberon_expr_t * size, oberon_type_t * base, oberon_type_t ** type)
+{
+	if(size -> is_item == 0)
+	{
+		oberon_error(ctx, "requires constant");
+	}
 
-	oberon_object_t * first;
-	first = oberon_make_param(ctx, modifer_token, name, type);
+	if(size -> item.mode != MODE_INTEGER)
+	{
+		oberon_error(ctx, "requires integer constant");
+	}
 
-	*num_decl += 1;
-	return first;
+	oberon_type_t * arr;
+	arr = *type;
+	arr -> class = OBERON_TYPE_ARRAY;
+	arr -> size = size -> item.integer;
+	arr -> base = base;
 }
 
-#define ISFPSECTION \
-	((ctx -> token == VAR) || (ctx -> token == IDENT))
+static void
+oberon_field_list(oberon_context_t * ctx, oberon_type_t * rec)
+{
+	if(ctx -> token == IDENT)
+	{
+		char * name;
+		oberon_type_t * type;
+		type = oberon_new_type_ptr(OBERON_TYPE_VOID);
 
-static oberon_type_t *
-oberon_formal_pars(oberon_context_t * ctx)
+		name = oberon_assert_ident(ctx);
+		oberon_assert_token(ctx, COLON);
+		oberon_type(ctx, &type);
+		oberon_define_field(ctx, rec, name, type);
+	}
+}
+
+static void
+oberon_qualident_type(oberon_context_t * ctx, oberon_type_t ** type)
 {
-	oberon_type_t * tp;
-	tp = oberon_new_type_ptr(OBERON_TYPE_PROCEDURE);
-	tp -> num_decl = 0;
-	tp -> base = ctx -> void_type;
-	tp -> decl = NULL;
+	char * name;
+	oberon_object_t * to;
 
-	oberon_assert_token(ctx, LPAREN);
+	to = oberon_qualident(ctx, &name, 0);
 
-	if(ISFPSECTION)
+	//name = oberon_assert_ident(ctx);
+	//to = oberon_find_object(ctx -> decl, name, 0);
+
+	if(to != NULL)
 	{
-		tp -> decl = oberon_fp_section(ctx, &tp -> num_decl);
-		while(ctx -> token == SEMICOLON)
+		if(to -> class != OBERON_CLASS_TYPE)
 		{
-			oberon_assert_token(ctx, SEMICOLON);
-			oberon_fp_section(ctx, &tp -> num_decl);
+			oberon_error(ctx, "not a type");
 		}
 	}
+	else
+	{
+		to = oberon_define_object(ctx -> decl, name, OBERON_CLASS_TYPE);
+		to -> type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+	}
 
-	oberon_assert_token(ctx, RPAREN);
+	*type = to -> type;
+}
 
-	if(ctx -> token == COLON)
+static void oberon_opt_formal_pars(oberon_context_t * ctx, oberon_type_t ** type);
+
+/*
+ * Правило граматики "type". Указатель type должен указывать на существующий объект!
+ */
+
+static void
+oberon_make_multiarray(oberon_context_t * ctx, oberon_expr_t * sizes, oberon_type_t * base, oberon_type_t ** type)
+{
+	if(sizes == NULL)
 	{
-		oberon_assert_token(ctx, COLON);
-		tp -> base = oberon_type(ctx);
+		*type = base;
+		return;
 	}
 
-	oberon_generator_init_type(ctx, tp);
-	return tp;
+	oberon_type_t * dim;
+	dim = oberon_new_type_ptr(OBERON_TYPE_VOID);
+
+	oberon_make_multiarray(ctx, sizes -> next, base, &dim);
+
+	oberon_make_array_type(ctx, sizes, dim, type);
 }
 
-static oberon_type_t *
-oberon_opt_formal_pars(oberon_context_t * ctx, int class)
+static void
+oberon_type(oberon_context_t * ctx, oberon_type_t ** type)
 {
-	oberon_type_t * signature;
+	if(ctx -> token == IDENT)
+	{
+		oberon_qualident_type(ctx, type);
+	}
+	else if(ctx -> token == ARRAY)
+	{
+		oberon_assert_token(ctx, ARRAY);
 
-	if(ctx -> token == LPAREN)
+		int num_sizes = 0;
+		oberon_expr_t * sizes;
+		oberon_expr_list(ctx, &num_sizes, &sizes, 1);
+
+		oberon_assert_token(ctx, OF);
+
+		oberon_type_t * base;
+		base = oberon_new_type_ptr(OBERON_TYPE_VOID);
+		oberon_type(ctx, &base);
+
+		oberon_make_multiarray(ctx, sizes, base, type);
+	}
+	else if(ctx -> token == RECORD)
+	{
+		oberon_type_t * rec;
+		rec = *type;
+		rec -> class = OBERON_TYPE_RECORD;
+		oberon_object_t * list = malloc(sizeof *list);
+	        memset(list, 0, sizeof *list);
+		rec -> num_decl = 0;
+		rec -> base = NULL;
+		rec -> decl = list;
+
+		oberon_assert_token(ctx, RECORD);
+		oberon_field_list(ctx, rec);
+		while(ctx -> token == SEMICOLON)
+		{
+			oberon_assert_token(ctx, SEMICOLON);
+			oberon_field_list(ctx, rec);
+		}
+		oberon_assert_token(ctx, END);
+
+		rec -> decl = rec -> decl -> next;
+		*type = rec;
+	}
+	else if(ctx -> token == POINTER)
+	{
+		oberon_assert_token(ctx, POINTER);
+		oberon_assert_token(ctx, TO);
+
+		oberon_type_t * base;
+		base = oberon_new_type_ptr(OBERON_TYPE_VOID);
+		oberon_type(ctx, &base);
+
+		oberon_type_t * ptr;
+		ptr = *type;
+		ptr -> class = OBERON_TYPE_POINTER;
+		ptr -> base = base;
+	}
+	else if(ctx -> token == PROCEDURE)
 	{
-		signature = oberon_formal_pars(ctx);
+		oberon_open_scope(ctx);
+		oberon_assert_token(ctx, PROCEDURE);
+		oberon_opt_formal_pars(ctx, type);
+		oberon_close_scope(ctx -> decl);
 	}
 	else
 	{
-		signature = oberon_new_type_ptr(class);
-		signature -> num_decl = 0;
-		signature -> base = ctx -> void_type;
-		signature -> decl = NULL;
-		oberon_generator_init_type(ctx, signature);
+		oberon_error(ctx, "invalid type declaration");
 	}
-
-	return signature;
 }
 
 static void
-oberon_make_return(oberon_context_t * ctx, oberon_expr_t * expr)
+oberon_type_decl(oberon_context_t * ctx)
 {
-	if(ctx -> result_type -> class == OBERON_TYPE_VOID)
+	char * name;
+	oberon_object_t * newtype;
+	oberon_type_t * type;
+
+	name = oberon_assert_ident(ctx);
+
+	newtype = oberon_find_object(ctx -> decl, name, 0);
+	if(newtype == NULL)
 	{
-		if(expr != NULL)
-		{
-			oberon_error(ctx, "procedure has no result type");
-		}
+		newtype = oberon_define_object(ctx -> decl, name, OBERON_CLASS_TYPE);
+		newtype -> type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+		assert(newtype -> type);
 	}
 	else
 	{
-		if(expr == NULL)
+		if(newtype -> class != OBERON_CLASS_TYPE)
 		{
-			oberon_error(ctx, "procedure requires expression on result");
+			oberon_error(ctx, "mult definition");
 		}
 
-		oberon_autocast_to(ctx, expr, ctx -> result_type);
+		if(newtype -> linked)
+		{
+			oberon_error(ctx, "mult definition - already linked");
+		}
 	}
 
-	ctx -> has_return = 1;
+	oberon_assert_token(ctx, EQUAL);
 
-	oberon_generate_return(ctx, expr);
+	type = newtype -> type;
+	oberon_type(ctx, &type);
+
+	if(type -> class == OBERON_TYPE_VOID)
+	{
+		oberon_error(ctx, "recursive alias declaration");
+	}
+
+	newtype -> type = type;
+	newtype -> linked = 1;
+}
+
+static void oberon_prevent_recursive_object(oberon_context_t * ctx, oberon_object_t * x);
+static void oberon_prevent_recursive_type(oberon_context_t * ctx, oberon_type_t * type);
+
+static void
+oberon_prevent_recursive_pointer(oberon_context_t * ctx, oberon_type_t * type)
+{
+	if(type -> class != OBERON_TYPE_POINTER
+		&& type -> class != OBERON_TYPE_ARRAY)
+	{
+		return;
+	}
+
+	if(type -> recursive)
+	{
+		oberon_error(ctx, "recursive pointer declaration");
+	}
+
+	if(type -> base -> class == OBERON_TYPE_POINTER)
+	{
+		oberon_error(ctx, "attempt to make pointer to pointer");
+	}
+
+	type -> recursive = 1;
+
+	oberon_prevent_recursive_pointer(ctx, type -> base);
+
+	type -> recursive = 0;
 }
 
 static void
-oberon_proc_decl(oberon_context_t * ctx)
+oberon_prevent_recursive_record(oberon_context_t * ctx, oberon_type_t * type)
 {
-	oberon_assert_token(ctx, PROCEDURE);
+	if(type -> class != OBERON_TYPE_RECORD)
+	{
+		return;
+	}
 
-	char * name;
-	name = oberon_assert_ident(ctx);
+	if(type -> recursive)
+	{
+		oberon_error(ctx, "recursive record declaration");
+	}
 
-	oberon_scope_t * this_proc_def_scope = ctx -> decl;
-	oberon_open_scope(ctx);
+	type -> recursive = 1;
 
-	oberon_type_t * signature;
-	signature = oberon_opt_formal_pars(ctx, OBERON_TYPE_PROCEDURE);
+	int num_fields = type -> num_decl;
+	oberon_object_t * field = type -> decl;
+	for(int i = 0; i < num_fields; i++)
+	{
+		oberon_prevent_recursive_object(ctx, field);
+		field = field -> next;
+	}
 
-	oberon_object_t * proc;
-	proc = oberon_define_proc(this_proc_def_scope, name, signature);
+	type -> recursive = 0;	
+}
+static void
+oberon_prevent_recursive_procedure(oberon_context_t * ctx, oberon_type_t * type)
+{
+	if(type -> class != OBERON_TYPE_PROCEDURE)
+	{
+		return;
+	}
 
-	ctx -> result_type = signature -> base;
-	ctx -> has_return = 0;
+	if(type -> recursive)
+	{
+		oberon_error(ctx, "recursive procedure declaration");
+	}
 
-	oberon_assert_token(ctx, SEMICOLON);
+	type -> recursive = 1;
 
-	oberon_generate_begin_proc(ctx, proc);
+	int num_fields = type -> num_decl;
+	oberon_object_t * field = type -> decl;
+	for(int i = 0; i < num_fields; i++)
+	{
+		oberon_prevent_recursive_object(ctx, field);
+		field = field -> next;
+	}
 
-	// TODO declarations
+	type -> recursive = 0;	
+}
 
-	if(ctx -> token == BEGIN)
+static void
+oberon_prevent_recursive_array(oberon_context_t * ctx, oberon_type_t * type)
+{
+	if(type -> class != OBERON_TYPE_ARRAY)
 	{
-		oberon_assert_token(ctx, BEGIN);
-		oberon_statement_seq(ctx);
+		return;
 	}
 
-	oberon_assert_token(ctx, END);
-	char * name2 = oberon_assert_ident(ctx);
-	if(strcmp(name2, name) != 0)
+	if(type -> recursive)
 	{
-		oberon_error(ctx, "procedure name not matched");
+		oberon_error(ctx, "recursive array declaration");
 	}
 
-	if(signature -> base -> class == OBERON_TYPE_VOID)
+	type -> recursive = 1;
+
+	oberon_prevent_recursive_type(ctx, type -> base);
+
+	type -> recursive = 0;
+}
+
+static void
+oberon_prevent_recursive_type(oberon_context_t * ctx, oberon_type_t * type)
+{
+	if(type -> class == OBERON_TYPE_POINTER)
 	{
-		oberon_make_return(ctx, NULL);
+		oberon_prevent_recursive_pointer(ctx, type);
 	}
+	else if(type -> class == OBERON_TYPE_RECORD)
+	{
+		oberon_prevent_recursive_record(ctx, type);
+	}
+	else if(type -> class == OBERON_TYPE_ARRAY)
+	{
+		oberon_prevent_recursive_array(ctx, type);
+	}
+	else if(type -> class == OBERON_TYPE_PROCEDURE)
+	{
+		oberon_prevent_recursive_procedure(ctx, type);
+	}
+}
 
-	if(ctx -> has_return == 0)
+static void
+oberon_prevent_recursive_object(oberon_context_t * ctx, oberon_object_t * x)
+{
+	switch(x -> class)
 	{
-		oberon_error(ctx, "procedure requires return");
+		case OBERON_CLASS_VAR:
+		case OBERON_CLASS_TYPE:
+		case OBERON_CLASS_PARAM:
+		case OBERON_CLASS_VAR_PARAM:
+		case OBERON_CLASS_FIELD:
+			oberon_prevent_recursive_type(ctx, x -> type);
+			break;
+		case OBERON_CLASS_CONST:
+		case OBERON_CLASS_PROC:
+		case OBERON_CLASS_MODULE:
+			break;
+		default:
+			oberon_error(ctx, "oberon_prevent_recursive_object: wat");
+			break;
 	}
-	ctx -> result_type = NULL;
+}
 
-	oberon_generate_end_proc(ctx);
-	oberon_close_scope(ctx -> decl);
+static void
+oberon_prevent_recursive_decl(oberon_context_t * ctx)
+{
+	oberon_object_t * x = ctx -> decl -> list -> next;
+
+	while(x)
+	{
+		oberon_prevent_recursive_object(ctx, x);
+		x = x -> next;
+	}
 }
 
+static void oberon_initialize_object(oberon_context_t * ctx, oberon_object_t * x);
+static void oberon_initialize_type(oberon_context_t * ctx, oberon_type_t * type);
+
 static void
-oberon_const_decl(oberon_context_t * ctx)
+oberon_initialize_record_fields(oberon_context_t * ctx, oberon_type_t * type)
 {
-	char * name;
-	oberon_item_t * value;
-	oberon_object_t * constant;
+	if(type -> class != OBERON_TYPE_RECORD)
+	{
+		return;
+	}
 
-	name = oberon_assert_ident(ctx);
-	oberon_assert_token(ctx, EQUAL);
-	value = oberon_const_expr(ctx);
+	int num_fields = type -> num_decl;
+	oberon_object_t * field = type -> decl;
+	for(int i = 0; i < num_fields; i++)
+	{
+		if(field -> type -> class == OBERON_TYPE_POINTER)
+		{
+			oberon_initialize_type(ctx, field -> type);
+		}
 
-	constant = oberon_define_object(ctx -> decl, name, OBERON_CLASS_CONST);
-	constant -> value = value;
+		oberon_initialize_object(ctx, field);
+		field = field -> next;
+	}
+
+	oberon_generator_init_record(ctx, type);
 }
 
 static void
-oberon_type_decl(oberon_context_t * ctx)
+oberon_initialize_type(oberon_context_t * ctx, oberon_type_t * type)
 {
-	char * name;
-	oberon_object_t * newtype;
-	oberon_type_t * type;
+	if(type -> class == OBERON_TYPE_VOID)
+	{
+		oberon_error(ctx, "undeclarated type");
+	}
 
-	name = oberon_assert_ident(ctx);
-	oberon_assert_token(ctx, EQUAL);
-	type = oberon_type(ctx);
+	if(type -> initialized)
+	{
+		return;
+	}
 
-	newtype = oberon_define_object(ctx -> decl, name, OBERON_CLASS_TYPE);
-	newtype -> type = type;
+	type -> initialized = 1;
+
+	if(type -> class == OBERON_TYPE_POINTER)
+	{
+		oberon_initialize_type(ctx, type -> base);
+		oberon_generator_init_type(ctx, type);
+	}
+	else if(type -> class == OBERON_TYPE_ARRAY)
+	{
+		oberon_initialize_type(ctx, type -> base);		
+		oberon_generator_init_type(ctx, type);
+	}
+	else if(type -> class == OBERON_TYPE_RECORD)
+	{
+		oberon_generator_init_type(ctx, type);
+		oberon_initialize_record_fields(ctx, type);
+	}
+	else if(type -> class == OBERON_TYPE_PROCEDURE)
+	{
+		int num_fields = type -> num_decl;
+		oberon_object_t * field = type -> decl;
+		for(int i = 0; i < num_fields; i++)
+		{
+			oberon_initialize_object(ctx, field);
+			field = field -> next;
+		}		
+
+		oberon_generator_init_type(ctx, type);
+	}
+	else
+	{
+		oberon_generator_init_type(ctx, type);
+	}
+}
+
+static void
+oberon_initialize_object(oberon_context_t * ctx, oberon_object_t * x)
+{
+	if(x -> initialized)
+	{
+		return;
+	}
+
+	x -> initialized = 1;
+
+	switch(x -> class)
+	{
+		case OBERON_CLASS_TYPE:
+			oberon_initialize_type(ctx, x -> type);
+			break;
+		case OBERON_CLASS_VAR:
+		case OBERON_CLASS_PARAM:
+		case OBERON_CLASS_VAR_PARAM:
+		case OBERON_CLASS_FIELD:
+			oberon_initialize_type(ctx, x -> type);
+			oberon_generator_init_var(ctx, x);
+			break;
+		case OBERON_CLASS_CONST:
+		case OBERON_CLASS_PROC:
+		case OBERON_CLASS_MODULE:
+			break;
+		default:
+			oberon_error(ctx, "oberon_initialize_object: wat");
+			break;
+	}
+}
+
+static void
+oberon_initialize_decl(oberon_context_t * ctx)
+{
+	oberon_object_t * x = ctx -> decl -> list;
+
+	while(x -> next)
+	{
+		oberon_initialize_object(ctx, x -> next);
+		x = x -> next;
+	}	
+}
+
+static void
+oberon_prevent_undeclarated_procedures(oberon_context_t * ctx)
+{
+	oberon_object_t * x = ctx -> decl -> list;
+
+	while(x -> next)
+	{
+		if(x -> next -> class == OBERON_CLASS_PROC)
+		{
+			if(x -> next -> linked == 0)
+			{
+				oberon_error(ctx, "unresolved forward declaration");
+			}
+		}
+		x = x -> next;
+	}	
 }
 
 static void
@@ -1576,11 +2254,16 @@ oberon_decl_seq(oberon_context_t * ctx)
 		}
 	}
 
+	oberon_prevent_recursive_decl(ctx);
+	oberon_initialize_decl(ctx);
+
 	while(ctx -> token == PROCEDURE)
 	{
 		oberon_proc_decl(ctx);
 		oberon_assert_token(ctx, SEMICOLON);
 	}
+
+	oberon_prevent_undeclarated_procedures(ctx);
 }
 
 static void
@@ -1590,13 +2273,6 @@ oberon_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
 	oberon_generate_assign(ctx, src, dst);
 }
 
-static void
-oberon_make_call(oberon_context_t * ctx, oberon_expr_t * desig)
-{
-	oberon_autocast_call(ctx, desig);
-	oberon_generate_call_proc(ctx, desig);
-}
-
 static void
 oberon_statement(oberon_context_t * ctx)
 {
@@ -1614,8 +2290,7 @@ oberon_statement(oberon_context_t * ctx)
 		}
 		else
 		{
-			item1 = oberon_opt_proc_parens(ctx, item1);
-			oberon_make_call(ctx, item1);
+			oberon_opt_proc_parens(ctx, item1);
 		}
 	}
 	else if(ctx -> token == RETURN)
@@ -1645,10 +2320,74 @@ oberon_statement_seq(oberon_context_t * ctx)
 	}
 }
 
+static void
+oberon_import_module(oberon_context_t * ctx, char * alias, char * name)
+{
+	oberon_module_t * m = ctx -> module_list;
+	while(m && strcmp(m -> name, name) != 0)
+	{
+		m = m -> next;
+	}
+
+	if(m == NULL)
+	{
+		const char * code;
+		code = ctx -> import_module(name);
+		if(code == NULL)
+		{
+			oberon_error(ctx, "no such module");
+		}
+
+		m = oberon_compile_module(ctx, code);
+		assert(m);
+	}
+
+	if(m -> ready == 0)
+	{
+		oberon_error(ctx, "cyclic module import");
+	}
+
+	oberon_object_t * ident;
+	ident = oberon_define_object(ctx -> decl, alias, OBERON_CLASS_MODULE);
+	ident -> module = m;
+}
+
+static void
+oberon_import_decl(oberon_context_t * ctx)
+{
+	char * alias;
+	char * name;
+
+	alias = name = oberon_assert_ident(ctx);
+	if(ctx -> token == ASSIGN)
+	{
+		oberon_assert_token(ctx, ASSIGN);
+		name = oberon_assert_ident(ctx);
+	}
+
+	oberon_import_module(ctx, alias, name);
+}
+
+static void
+oberon_import_list(oberon_context_t * ctx)
+{
+	oberon_assert_token(ctx, IMPORT);
+
+	oberon_import_decl(ctx);
+	while(ctx -> token == COMMA)
+	{
+		oberon_assert_token(ctx, COMMA);
+		oberon_import_decl(ctx);
+	}
+
+	oberon_assert_token(ctx, SEMICOLON);
+}
+
 static void
 oberon_parse_module(oberon_context_t * ctx)
 {
-	char *name1, *name2;
+	char * name1;
+	char * name2;
 	oberon_read_token(ctx);
 
 	oberon_assert_token(ctx, MODULE);
@@ -1656,12 +2395,24 @@ oberon_parse_module(oberon_context_t * ctx)
 	oberon_assert_token(ctx, SEMICOLON);
 	ctx -> mod -> name = name1;
 
+	oberon_object_t * this_module;
+	this_module = oberon_define_object(ctx -> decl, name1, OBERON_CLASS_MODULE);
+	this_module -> module = ctx -> mod;
+
+	if(ctx -> token == IMPORT)
+	{
+		oberon_import_list(ctx);
+	}
+
+	ctx -> decl -> parent = this_module;
+
 	oberon_decl_seq(ctx);
 
+	oberon_generate_begin_module(ctx);
+
 	if(ctx -> token == BEGIN)
 	{
 		oberon_assert_token(ctx, BEGIN);
-		oberon_generate_begin_module(ctx);
 		oberon_statement_seq(ctx);
 		oberon_generate_end_module(ctx);
 	}
@@ -1686,6 +2437,10 @@ register_default_types(oberon_context_t * ctx)
 	ctx -> void_type = oberon_new_type_ptr(OBERON_TYPE_VOID);
 	oberon_generator_init_type(ctx, ctx -> void_type);
 
+	ctx -> void_ptr_type = oberon_new_type_ptr(OBERON_TYPE_POINTER);
+	ctx -> void_ptr_type -> base = ctx -> void_type;
+	oberon_generator_init_type(ctx, ctx -> void_ptr_type);
+
 	ctx -> int_type = oberon_new_type_integer(sizeof(int));
 	oberon_define_type(ctx -> world_scope, "INTEGER", ctx -> int_type);
 
@@ -1693,19 +2448,62 @@ register_default_types(oberon_context_t * ctx)
 	oberon_define_type(ctx -> world_scope, "BOOLEAN", ctx -> bool_type);
 }
 
+static void
+oberon_new_intrinsic(oberon_context_t * ctx, char * name, GenerateFuncCallback f, GenerateProcCallback p)
+{
+	oberon_object_t * proc;
+	proc = oberon_define_object(ctx -> decl, name, OBERON_CLASS_PROC);
+	proc -> sysproc = 1;
+	proc -> genfunc = f;
+	proc -> genproc = p;
+	proc -> type = oberon_new_type_ptr(OBERON_TYPE_PROCEDURE);
+}
+
+static oberon_expr_t *
+oberon_make_abs_call(oberon_context_t * ctx, int num_args, oberon_expr_t * list_args)
+{
+	if(num_args < 1)
+	{
+		oberon_error(ctx, "too few arguments");
+	}
+
+	if(num_args > 1)
+	{
+		oberon_error(ctx, "too mach arguments");
+	}
+
+	oberon_expr_t * arg;
+	arg = list_args;
+
+	oberon_type_t * result_type;
+	result_type = arg -> result;
+	
+	if(result_type -> class != OBERON_TYPE_INTEGER)
+	{
+		oberon_error(ctx, "ABS accepts only integers");
+	}
+
+
+	oberon_expr_t * expr;
+	expr = oberon_new_operator(OP_ABS, result_type, arg, NULL);
+	return expr;
+}
+
 oberon_context_t *
-oberon_create_context()
+oberon_create_context(ModuleImportCallback import_module)
 {
-	oberon_context_t * ctx = malloc(sizeof *ctx);
-	memset(ctx, 0, sizeof *ctx);
+	oberon_context_t * ctx = calloc(1, sizeof *ctx);
 
 	oberon_scope_t * world_scope;
 	world_scope = oberon_open_scope(ctx);
 	ctx -> world_scope = world_scope;
 
+	ctx -> import_module = import_module;
+
 	oberon_generator_init_context(ctx);
 
-	register_default_types(ctx);	
+	register_default_types(ctx);
+	oberon_new_intrinsic(ctx, "ABS", oberon_make_abs_call, NULL);
 
 	return ctx;
 }
@@ -1718,21 +2516,41 @@ oberon_destroy_context(oberon_context_t * ctx)
 }
 
 oberon_module_t *
-oberon_compile_module(oberon_context_t * ctx, const char * code)
+oberon_compile_module(oberon_context_t * ctx, const char * newcode)
 {
-	oberon_module_t * mod = malloc(sizeof *mod);
-	memset(mod, 0, sizeof *mod);
-	ctx -> mod = mod;
+	const char * code = ctx -> code;
+	int code_index = ctx -> code_index;
+	char c = ctx -> c;
+	int token = ctx -> token;
+	char * string = ctx -> string;
+	int integer = ctx -> integer;
+	oberon_scope_t * decl = ctx -> decl;
+	oberon_module_t * mod = ctx -> mod;
 
 	oberon_scope_t * module_scope;
 	module_scope = oberon_open_scope(ctx);
-	mod -> decl = module_scope;
 
-	oberon_init_scaner(ctx, code);
+	oberon_module_t * module;
+	module = calloc(1, sizeof *module);
+	module -> decl = module_scope;
+	module -> next = ctx -> module_list;
+
+	ctx -> mod = module;
+	ctx -> module_list = module;
+
+	oberon_init_scaner(ctx, newcode);
 	oberon_parse_module(ctx);
 
-	oberon_generate_code(ctx);
+	module -> ready = 1;
+
+	ctx -> code = code;
+	ctx -> code_index = code_index;
+	ctx -> c = c;
+	ctx -> token = token;
+	ctx -> string = string;
+	ctx -> integer = integer;
+	ctx -> decl = decl;
+	ctx -> mod = mod;
 
-	ctx -> mod = NULL;
-	return mod;
+	return module;
 }