X-Git-Url: http://deadsoftware.ru/gitweb?a=blobdiff_plain;f=oberon.c;h=6dd84f16b6b9c3108973c087636865c661735bc3;hb=1bf625553dc35ac4a5c1afceb6950fd44776a424;hp=0aa8d45bf1304f6a95fe211480359d30afa7c9ef;hpb=90ad7d921e60c24b11bc08cd173c0e1c80f9b06d;p=dsw-obn.git

diff --git a/oberon.c b/oberon.c
index 0aa8d45..6dd84f1 100644
--- a/oberon.c
+++ b/oberon.c
@@ -3,6 +3,7 @@
 #include <stdarg.h>
 #include <ctype.h>
 #include <string.h>
+#include <assert.h>
 
 #include "oberon.h"
 #include "generator.h"
@@ -38,7 +39,20 @@ enum {
 	MOD,
 	AND,
 	NOT,
-	PROCEDURE
+	PROCEDURE,
+	COMMA,
+	RETURN,
+	CONST,
+	TYPE,
+	ARRAY,
+	OF,
+	LBRACE,
+	RBRACE,
+	RECORD,
+	POINTER,
+	TO,
+	UPARROW,
+	NIL
 };
 
 // =======================================================================
@@ -60,6 +74,33 @@ oberon_error(oberon_context_t * ctx, const char * fmt, ...)
 	exit(1);
 }
 
+static oberon_type_t *
+oberon_new_type_ptr(int class)
+{
+	oberon_type_t * x = malloc(sizeof *x);
+	memset(x, 0, sizeof *x);
+	x -> class = class;
+	return x;
+}
+
+static oberon_type_t *
+oberon_new_type_integer(int size)
+{
+	oberon_type_t * x;
+	x = oberon_new_type_ptr(OBERON_TYPE_INTEGER);
+	x -> size = size;
+	return x;
+}
+
+static oberon_type_t *
+oberon_new_type_boolean(int size)
+{
+	oberon_type_t * x;
+	x = oberon_new_type_ptr(OBERON_TYPE_BOOLEAN);
+	x -> size = size;
+	return x;
+}
+
 // =======================================================================
 //   TABLE
 // ======================================================================= 
@@ -77,6 +118,12 @@ oberon_open_scope(oberon_context_t * 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;
 }
@@ -106,12 +153,42 @@ 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;
 
 	return newvar;
 }
 
+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)
+	{
+		x = x -> next;
+	}
+
+	if(x -> next)
+	{
+		oberon_error(ctx, "multiple definition");
+	}
+
+	oberon_object_t * field = malloc(sizeof *field);
+	memset(field, 0, sizeof *field);
+	field -> name = name;
+	field -> class = OBERON_CLASS_FIELD;
+	field -> type = type;
+	field -> local = 1;
+	field -> parent = NULL;
+
+	rec -> num_decl += 1;
+	x -> next = field;
+}
+
 static oberon_object_t *
 oberon_find_object_in_list(oberon_object_t * list, char * name)
 {
@@ -124,7 +201,7 @@ 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;
 
@@ -135,7 +212,7 @@ 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);
 	}
@@ -143,15 +220,35 @@ oberon_find_object(oberon_scope_t * scope, char * name)
 	return result;
 }
 
-static void
+static oberon_object_t *
+oberon_find_field(oberon_context_t * ctx, oberon_type_t * rec, char * name)
+{
+	oberon_object_t * x = rec -> decl;
+	for(int i = 0; i < rec -> num_decl; i++)
+	{
+		if(strcmp(x -> name, name) == 0)
+		{
+			return x;
+		}
+		x = x -> next;
+	}
+
+	oberon_error(ctx, "field not defined");
+
+	return NULL;
+}
+
+static oberon_object_t *
 oberon_define_type(oberon_scope_t * scope, char * name, oberon_type_t * type)
 {
 	oberon_object_t * id;
 	id = oberon_define_object(scope, name, OBERON_CLASS_TYPE);
 	id -> type = type;
 	oberon_generator_init_type(scope -> ctx, type);
+	return id;
 }
 
+/*
 static oberon_type_t *
 oberon_find_type(oberon_scope_t * scope, char * name)
 {
@@ -163,14 +260,15 @@ oberon_find_type(oberon_scope_t * scope, char * name)
 
 	return x -> type;
 }
+*/
 
-static void
-oberon_define_var(oberon_scope_t * scope, char * name, oberon_type_t * type)
+static oberon_object_t *
+oberon_define_var(oberon_scope_t * scope, int class, char * name, oberon_type_t * type)
 {
 	oberon_object_t * var;
-	var = oberon_define_object(scope, name, OBERON_CLASS_VAR);
+	var = oberon_define_object(scope, name, class);
 	var -> type = type;
-	oberon_generator_init_var(scope -> ctx, var);
+	return var;
 }
 
 /*
@@ -188,14 +286,16 @@ oberon_find_var(oberon_scope_t * scope, char * name)
 }
 */
 
+/*
 static oberon_object_t *
-oberon_define_proc(oberon_scope_t * scope, char * name)
+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);
-	oberon_generator_init_proc(scope -> ctx, proc);
+	proc -> type = signature;
 	return proc;
 }
+*/
 
 // =======================================================================
 //   SCANER
@@ -279,6 +379,42 @@ oberon_read_ident(oberon_context_t * ctx)
 	{
 		ctx -> token = PROCEDURE;
 	}
+	else if(strcmp(ident, "RETURN") == 0)
+	{
+		ctx -> token = RETURN;
+	}
+	else if(strcmp(ident, "CONST") == 0)
+	{
+		ctx -> token = CONST;
+	}
+	else if(strcmp(ident, "TYPE") == 0)
+	{
+		ctx -> token = TYPE;
+	}
+	else if(strcmp(ident, "ARRAY") == 0)
+	{
+		ctx -> token = ARRAY;
+	}
+	else if(strcmp(ident, "OF") == 0)
+	{
+		ctx -> token = OF;
+	}
+	else if(strcmp(ident, "RECORD") == 0)
+	{
+		ctx -> token = RECORD;
+	}
+	else if(strcmp(ident, "POINTER") == 0)
+	{
+		ctx -> token = POINTER;
+	}
+	else if(strcmp(ident, "TO") == 0)
+	{
+		ctx -> token = TO;
+	}
+	else if(strcmp(ident, "NIL") == 0)
+	{
+		ctx -> token = NIL;
+	}
 }
 
 static void
@@ -399,6 +535,22 @@ oberon_read_symbol(oberon_context_t * ctx)
 			ctx -> token = NOT;
 			oberon_get_char(ctx);
 			break;
+		case ',':
+			ctx -> token = COMMA;
+			oberon_get_char(ctx);
+			break;
+		case '[':
+			ctx -> token = LBRACE;
+			oberon_get_char(ctx);
+			break;
+		case ']':
+			ctx -> token = RBRACE;
+			oberon_get_char(ctx);
+			break;
+		case '^':
+			ctx -> token = UPARROW;
+			oberon_get_char(ctx);
+			break;
 		default:
 			oberon_error(ctx, "invalid char");
 			break;
@@ -433,6 +585,8 @@ 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 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)
@@ -498,162 +652,565 @@ oberon_make_unary_op(oberon_context_t * ctx, int token, oberon_expr_t * a)
 	return expr;
 }
 
-static oberon_expr_t *
-oberon_factor(oberon_context_t * ctx)
+static void
+oberon_expr_list(oberon_context_t * ctx, int * num_expr, oberon_expr_t ** first, int const_expr)
 {
-	char * name;
-	oberon_object_t * var;
-	oberon_expr_t * expr;
+	oberon_expr_t * last;
 
-	switch(ctx -> token)
+	*num_expr = 1;
+	*first = last = oberon_expr(ctx);
+	while(ctx -> token == COMMA)
 	{
-		case IDENT:
-			name = oberon_assert_ident(ctx);
-			var = oberon_find_object(ctx -> decl, name);
-			if(var -> class == OBERON_CLASS_VAR)
-			{
-				expr = oberon_new_item(MODE_VAR, var -> type);
-			}
-			else if(var -> class == OBERON_CLASS_PROC)
-			{
-				expr = oberon_new_item(MODE_CALL, var -> type);
-			}
-			else
-			{
-				oberon_error(ctx, "invalid desinator");
-			}
-			expr -> item.var = var;
-			break;
-		case INTEGER:
-			expr = oberon_new_item(MODE_INTEGER, ctx -> int_type);
-			expr -> item.integer = ctx -> integer;
-			oberon_assert_token(ctx, INTEGER);
-			break;
-		case TRUE:
-			expr = oberon_new_item(MODE_BOOLEAN, ctx -> bool_type);
-			expr -> item.boolean = 1;
-			oberon_assert_token(ctx, TRUE);
-			break;
-		case FALSE:
-			expr = oberon_new_item(MODE_BOOLEAN, ctx -> bool_type);
-			expr -> item.boolean = 0;
-			oberon_assert_token(ctx, FALSE);
-			break;
-		case LPAREN:
-			oberon_assert_token(ctx, LPAREN);
-			expr = oberon_expr(ctx);
-			oberon_assert_token(ctx, RPAREN);
-			break;
-		case NOT:
-			oberon_assert_token(ctx, NOT);
-			expr = oberon_factor(ctx);
-			expr = oberon_make_unary_op(ctx, NOT, expr);
-			break;
-		default:
-			oberon_error(ctx, "invalid expression");
-	}
+		oberon_assert_token(ctx, COMMA);
+		oberon_expr_t * current;
 
-	return expr;
-}
+		if(const_expr)
+		{
+			current = (oberon_expr_t *) oberon_const_expr(ctx);
+		}
+		else
+		{
+			current = oberon_expr(ctx);
+		}
 
-/*
- * oberon_autocast_binary_op автоматически переобразовывеат тип по след. правилам:
- *   1. Классы обоих типов должны быть одинаковы
- *   2. В качестве результата должен быть выбран больший тип.
- *   3. Если размер результат не должен быть меньше чем базовый int
- */
+		last -> next = current;
+		last = current;
+		*num_expr += 1;
+	}
+}
 
-static void
-oberon_autocast_binary_op(oberon_context_t * ctx, oberon_type_t * a, oberon_type_t * b, oberon_type_t ** result)
+static oberon_expr_t *
+oberon_autocast_to(oberon_context_t * ctx, oberon_expr_t * expr, oberon_type_t * pref)
 {
-	if((a -> class) != (b -> class))
+	if(pref -> class != expr -> result -> class)
 	{
 		oberon_error(ctx, "incompatible types");
 	}
 
-	if((a -> size) > (b -> size))
+	if(pref -> class == OBERON_TYPE_INTEGER)
 	{
-		*result = a;
+		if(expr -> result -> class > pref -> class)
+		{
+			oberon_error(ctx, "incompatible size");
+		}
 	}
-	else
+	else if(pref -> class == OBERON_TYPE_RECORD)
 	{
-		*result = b;
+		if(expr -> result != pref)
+		{
+			printf("oberon_autocast_to: rec %p != %p\n", expr -> result, pref);
+			oberon_error(ctx, "incompatible record types");
+		}
 	}
-
-	if(((*result) -> class) == OBERON_TYPE_INTEGER)
+	else if(pref -> class == OBERON_TYPE_POINTER)
 	{
-		if(((*result) -> size) < (ctx -> int_type -> size))
+		if(expr -> result -> base != pref -> base)
 		{
-			*result = ctx -> int_type;
+			if(expr -> result -> base -> class != OBERON_TYPE_VOID)
+			{
+				oberon_error(ctx, "incompatible pointer types");
+			}
 		}
 	}
 
-	/* TODO: cast types */
+	// TODO cast
+
+	return expr;
 }
 
-#define ITMAKESBOOLEAN(x) \
-	(((x) >= EQUAL && (x) <= GEQ) || ((x) == OR) || ((x) == AND))
+static void
+oberon_autocast_call(oberon_context_t * ctx, oberon_expr_t * desig)
+{
+	if(desig -> is_item == 0)
+	{
+		oberon_error(ctx, "expected item");
+	}
 
-#define ITUSEONLYINTEGER(x) \
-	((x) >= LESS && (x) <= GEQ)
+	if(desig -> item.mode != MODE_CALL)
+	{
+		oberon_error(ctx, "expected mode CALL");
+	}
 
-#define ITUSEONLYBOOLEAN(x) \
-	(((x) == OR) || ((x) == AND))
+	if(desig -> item.var -> class != OBERON_CLASS_PROC)
+	{
+		oberon_error(ctx, "only procedures can be called");
+	}
 
-static oberon_expr_t *
-oberon_make_bin_op(oberon_context_t * ctx, int token, oberon_expr_t * a, oberon_expr_t * b)
-{
-	oberon_expr_t * expr;
-	oberon_type_t * result;
+	oberon_type_t * fn = desig -> item.var -> type;
+	int num_args = desig -> item.num_args;
+	int num_decl = fn -> num_decl;
 
-	oberon_autocast_binary_op(ctx, a -> result, b -> result, &result);
+	if(num_args < num_decl)
+	{
+		oberon_error(ctx, "too few arguments");
+	}
+	else if(num_args > num_decl)
+	{
+		oberon_error(ctx, "too many arguments");
+	}
 
-	if(ITMAKESBOOLEAN(token))
+	oberon_expr_t * arg = desig -> item.args;
+	oberon_object_t * param = fn -> decl;
+	for(int i = 0; i < num_args; i++)
 	{
-		if(ITUSEONLYINTEGER(token))
+		if(param -> class == OBERON_CLASS_VAR_PARAM)
 		{
-			if(a -> result -> class != OBERON_TYPE_INTEGER
-				&& b -> result -> class != OBERON_TYPE_INTEGER)
-			{
-				oberon_error(ctx, "used only with integer types");
-			}
-		}
-		else if(ITUSEONLYBOOLEAN(token))
-		{
-			if(a -> result -> class != OBERON_TYPE_BOOLEAN
-				&& b -> result -> class != OBERON_TYPE_BOOLEAN)
+			if(arg -> is_item)
 			{
-				oberon_error(ctx, "used only with boolean type");
+				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;
+	}
+}
 
-		if(token == EQUAL)
-		{
-			expr = oberon_new_operator(OP_EQ, result, a, b);
-		}
-		else if(token == NEQ)
-		{
-			expr = oberon_new_operator(OP_NEQ, result, a, b);
-		}
-		else if(token == LESS)
+static oberon_expr_t *
+oberon_make_call_func(oberon_context_t * ctx, oberon_object_t * proc, int num_args, oberon_expr_t * list_args)
+{
+	if(proc -> class != OBERON_CLASS_PROC)
+	{
+		oberon_error(ctx, "not a procedure");
+	}
+
+	oberon_expr_t * call;
+
+	if(proc -> sysproc)
+	{
+		if(proc -> genfunc == NULL)
 		{
-			expr = oberon_new_operator(OP_LSS, result, a, b);
+			oberon_error(ctx, "not a function-procedure");
 		}
-		else if(token == LEQ)
+
+		call = proc -> genfunc(ctx, num_args, list_args);
+	}
+	else
+	{
+		if(proc -> type -> base -> class == OBERON_TYPE_VOID)
 		{
-			expr = oberon_new_operator(OP_LEQ, result, a, b);
+			oberon_error(ctx, "attempt to call procedure in expression");
 		}
-		else if(token == GREAT)
+
+		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)
+{
+	if(proc -> class != OBERON_CLASS_PROC)
+	{
+		oberon_error(ctx, "not a procedure");
+	}
+
+	if(proc -> sysproc)
+	{
+		if(proc -> genproc == NULL)
 		{
-			expr = oberon_new_operator(OP_GRT, result, a, b);
+			oberon_error(ctx, "requres non-typed procedure");
 		}
-		else if(token == GEQ)
+
+		proc -> genproc(ctx, num_args, list_args);
+	}
+	else
+	{
+		if(proc -> type -> base -> class != OBERON_TYPE_VOID)
 		{
-			expr = oberon_new_operator(OP_GEQ, result, a, b);
+			oberon_error(ctx, "attempt to call function as non-typed procedure");
 		}
-		else if(token == OR)
-		{
-			expr = oberon_new_operator(OP_LOGIC_OR, result, a, b);
+
+		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) \
+	|| ((x) == IDENT) \
+	|| ((x) == INTEGER) \
+	|| ((x) == LPAREN) \
+	|| ((x) == NOT) \
+	|| ((x) == TRUE) \
+	|| ((x) == FALSE))
+
+static oberon_expr_t *
+oberno_make_dereferencing(oberon_context_t * ctx, oberon_expr_t * expr)
+{
+	if(expr -> result -> class != OBERON_TYPE_POINTER)
+	{
+		oberon_error(ctx, "not a pointer");
+	}
+
+	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)
+	{
+		desig = oberno_make_dereferencing(ctx, desig);
+	}
+
+	assert(desig -> is_item);
+
+	if(desig -> result -> class != OBERON_TYPE_ARRAY)
+	{
+		oberon_error(ctx, "not array");
+	}
+
+	oberon_type_t * base;
+	base = desig -> result -> base;
+
+	if(index -> result -> class != OBERON_TYPE_INTEGER)
+	{
+		oberon_error(ctx, "index must be integer");
+	}
+
+	// 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 = 1;
+	selector -> item.args = index;
+
+	return selector;
+}
+
+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);
+
+	if(expr -> result -> class != OBERON_TYPE_RECORD)
+	{
+		oberon_error(ctx, "not record");
+	}
+
+	oberon_type_t * rec = expr -> result;
+
+	oberon_object_t * field;
+	field = oberon_find_field(ctx, rec, name);
+
+	oberon_expr_t * selector;
+	selector = oberon_new_item(MODE_FIELD, field -> type);
+	selector -> item.var = field;
+	selector -> item.parent = (oberon_item_t *) expr;
+
+	return selector;
+}
+
+#define ISSELECTOR(x) \
+	(((x) == LBRACE) \
+	|| ((x) == DOT) \
+	|| ((x) == UPARROW))
+
+static oberon_expr_t *
+oberon_designator(oberon_context_t * ctx)
+{
+	char * name;
+	oberon_object_t * var;
+	oberon_expr_t * expr;
+
+	name = oberon_assert_ident(ctx);
+	var = oberon_find_object(ctx -> decl, name, 1);
+
+	switch(var -> class)
+	{
+		case OBERON_CLASS_CONST:
+			// TODO copy value
+			expr = (oberon_expr_t *) var -> value;
+			break;
+		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_make_call_expr(var, 0, NULL);
+			expr = oberon_new_item(MODE_CALL, var -> type);
+			break;
+		default:
+			oberon_error(ctx, "invalid designator");
+			break;
+	}
+	expr -> item.var = var;
+
+	while(ISSELECTOR(ctx -> token))
+	{
+		switch(ctx -> token)
+		{
+			case DOT:
+				oberon_assert_token(ctx, DOT);
+				name = oberon_assert_ident(ctx);
+				expr = oberon_make_record_selector(ctx, expr, name);
+				break;
+			case LBRACE:
+				oberon_assert_token(ctx, LBRACE);
+				int num_indexes = 0;
+				oberon_expr_t * indexes = NULL;
+				oberon_expr_list(ctx, &num_indexes, &indexes, 0);
+				oberon_assert_token(ctx, RBRACE);
+
+				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");
+				break;
+		}
+	}
+	return expr;
+}
+
+static oberon_expr_t *
+oberon_opt_func_parens(oberon_context_t * ctx, oberon_expr_t * expr)
+{
+	assert(expr -> is_item == 1);
+
+	if(ctx -> token == LPAREN)
+	{
+		oberon_assert_token(ctx, LPAREN);
+
+		int num_args = 0;
+		oberon_expr_t * arguments = NULL;
+
+		if(ISEXPR(ctx -> token))
+		{
+			oberon_expr_list(ctx, &num_args, &arguments, 0);
+		}
+
+		expr = oberon_make_call_func(ctx, expr -> item.var, num_args, arguments);
+
+		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);
+
+	if(ctx -> token == LPAREN)
+	{
+		oberon_assert_token(ctx, LPAREN);
+
+		int num_args = 0;
+		oberon_expr_t * arguments = NULL;
+
+		if(ISEXPR(ctx -> token))
+		{
+			oberon_expr_list(ctx, &num_args, &arguments, 0);
+		}
+
+		oberon_make_call_proc(ctx, expr -> item.var, num_args, arguments);
+
+		oberon_assert_token(ctx, RPAREN);
+	}
+}
+
+static oberon_expr_t *
+oberon_factor(oberon_context_t * ctx)
+{
+	oberon_expr_t * expr;
+
+	switch(ctx -> token)
+	{
+		case IDENT:
+			expr = oberon_designator(ctx);
+			expr = oberon_opt_func_parens(ctx, expr);
+			break;
+		case INTEGER:
+			expr = oberon_new_item(MODE_INTEGER, ctx -> int_type);
+			expr -> item.integer = ctx -> integer;
+			oberon_assert_token(ctx, INTEGER);
+			break;
+		case TRUE:
+			expr = oberon_new_item(MODE_BOOLEAN, ctx -> bool_type);
+			expr -> item.boolean = 1;
+			oberon_assert_token(ctx, TRUE);
+			break;
+		case FALSE:
+			expr = oberon_new_item(MODE_BOOLEAN, ctx -> bool_type);
+			expr -> item.boolean = 0;
+			oberon_assert_token(ctx, FALSE);
+			break;
+		case LPAREN:
+			oberon_assert_token(ctx, LPAREN);
+			expr = oberon_expr(ctx);
+			oberon_assert_token(ctx, RPAREN);
+			break;
+		case NOT:
+			oberon_assert_token(ctx, NOT);
+			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");
+	}
+
+	return expr;
+}
+
+/*
+ * oberon_autocast_binary_op автоматически переобразовывеат тип по след. правилам:
+ *   1. Классы обоих типов должны быть одинаковы
+ *   2. В качестве результата должен быть выбран больший тип.
+ *   3. Если размер результат не должен быть меньше чем базовый int
+ */
+
+static void
+oberon_autocast_binary_op(oberon_context_t * ctx, oberon_type_t * a, oberon_type_t * b, oberon_type_t ** result)
+{
+	if((a -> class) != (b -> class))
+	{
+		oberon_error(ctx, "incompatible types");
+	}
+
+	if((a -> size) > (b -> size))
+	{
+		*result = a;
+	}
+	else
+	{
+		*result = b;
+	}
+
+	if(((*result) -> class) == OBERON_TYPE_INTEGER)
+	{
+		if(((*result) -> size) < (ctx -> int_type -> size))
+		{
+			*result = ctx -> int_type;
+		}
+	}
+
+	/* TODO: cast types */
+}
+
+#define ITMAKESBOOLEAN(x) \
+	(((x) >= EQUAL && (x) <= GEQ) || ((x) == OR) || ((x) == AND))
+
+#define ITUSEONLYINTEGER(x) \
+	((x) >= LESS && (x) <= GEQ)
+
+#define ITUSEONLYBOOLEAN(x) \
+	(((x) == OR) || ((x) == AND))
+
+static oberon_expr_t *
+oberon_make_bin_op(oberon_context_t * ctx, int token, oberon_expr_t * a, oberon_expr_t * b)
+{
+	oberon_expr_t * expr;
+	oberon_type_t * result;
+
+	if(ITMAKESBOOLEAN(token))
+	{
+		if(ITUSEONLYINTEGER(token))
+		{
+			if(a -> result -> class != OBERON_TYPE_INTEGER
+				|| b -> result -> class != OBERON_TYPE_INTEGER)
+			{
+				oberon_error(ctx, "used only with integer types");
+			}
+		}
+		else if(ITUSEONLYBOOLEAN(token))
+		{
+			if(a -> result -> class != OBERON_TYPE_BOOLEAN
+				|| b -> result -> class != OBERON_TYPE_BOOLEAN)
+			{
+				oberon_error(ctx, "used only with boolean type");
+			}
+		}
+
+		result = ctx -> bool_type;
+
+		if(token == EQUAL)
+		{
+			expr = oberon_new_operator(OP_EQ, result, a, b);
+		}
+		else if(token == NEQ)
+		{
+			expr = oberon_new_operator(OP_NEQ, result, a, b);
+		}
+		else if(token == LESS)
+		{
+			expr = oberon_new_operator(OP_LSS, result, a, b);
+		}
+		else if(token == LEQ)
+		{
+			expr = oberon_new_operator(OP_LEQ, result, a, b);
+		}
+		else if(token == GREAT)
+		{
+			expr = oberon_new_operator(OP_GRT, result, a, b);
+		}
+		else if(token == GEQ)
+		{
+			expr = oberon_new_operator(OP_GEQ, result, a, b);
+		}
+		else if(token == OR)
+		{
+			expr = oberon_new_operator(OP_LOGIC_OR, result, a, b);
 		}
 		else if(token == AND)
 		{
@@ -666,6 +1223,8 @@ oberon_make_bin_op(oberon_context_t * ctx, int token, oberon_expr_t * a, oberon_
 	}
 	else
 	{
+		oberon_autocast_binary_op(ctx, a -> result, b -> result, &result);
+
 		if(token == PLUS)
 		{
 			expr = oberon_new_operator(OP_ADD, result, a, b);
@@ -717,222 +1276,931 @@ oberon_term_expr(oberon_context_t * ctx)
 		expr = oberon_make_bin_op(ctx, token, expr, inter);
 	}
 
-	return expr;
-}
+	return expr;
+}
+
+#define ISADDOP(x) \
+	((x) >= PLUS && (x) <= OR)
+
+static oberon_expr_t *
+oberon_simple_expr(oberon_context_t * ctx)
+{
+	oberon_expr_t * expr;
+
+	int minus = 0;
+	if(ctx -> token == PLUS)
+	{
+		minus = 0;
+		oberon_assert_token(ctx, PLUS);
+	}
+	else if(ctx -> token == MINUS)
+	{
+		minus = 1;
+		oberon_assert_token(ctx, MINUS);
+	}
+
+	expr = oberon_term_expr(ctx);
+	while(ISADDOP(ctx -> token))
+	{
+		int token = ctx -> token;
+		oberon_read_token(ctx);
+
+		oberon_expr_t * inter = oberon_term_expr(ctx);
+		expr = oberon_make_bin_op(ctx, token, expr, inter);
+	}
+
+	if(minus)
+	{
+		expr = oberon_make_unary_op(ctx, MINUS, expr);
+	}
+
+	return expr;
+}
+
+#define ISRELATION(x) \
+	((x) >= EQUAL && (x) <= GEQ)
+
+static oberon_expr_t *
+oberon_expr(oberon_context_t * ctx)
+{
+	oberon_expr_t * expr;
+
+	expr = oberon_simple_expr(ctx);
+	while(ISRELATION(ctx -> token))
+	{
+		int token = ctx -> token;
+		oberon_read_token(ctx);
+
+		oberon_expr_t * inter = oberon_simple_expr(ctx);
+		expr = oberon_make_bin_op(ctx, token, expr, inter);
+	}
+
+	return expr;
+}
+
+static oberon_item_t *
+oberon_const_expr(oberon_context_t * ctx)
+{
+	oberon_expr_t * expr;
+	expr = oberon_expr(ctx);
+
+	if(expr -> is_item == 0)
+	{
+		oberon_error(ctx, "const expression are required");
+	}
+
+	return (oberon_item_t *) expr;
+}
+
+// =======================================================================
+//   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)
+{
+	if(ctx -> token != token)
+	{
+		oberon_error(ctx, "unexpected token %i (%i)", ctx -> token, token);
+	}
+}
+
+static void
+oberon_assert_token(oberon_context_t * ctx, int token)
+{
+	oberon_expect_token(ctx, token);
+	oberon_read_token(ctx);
+}
+
+static char *
+oberon_assert_ident(oberon_context_t * ctx)
+{
+	oberon_expect_token(ctx, IDENT);
+	char * ident = ctx -> string;
+	oberon_read_token(ctx);
+	return ident;
+}
+
+static void
+oberon_var_decl(oberon_context_t * ctx)
+{
+	char * name;
+	oberon_type_t * type;
+	type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+
+	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 oberon_object_t *
+oberon_make_param(oberon_context_t * ctx, int token, char * name, oberon_type_t * type)
+{
+	oberon_object_t * param;
+
+	if(token == VAR)
+	{
+		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_object_t *
+oberon_fp_section(oberon_context_t * ctx, int * num_decl)
+{
+	int modifer_token = ctx -> token;
+	if(ctx -> token == VAR)
+	{
+		oberon_read_token(ctx);
+	}
+
+	char * name;
+	name = oberon_assert_ident(ctx);
+
+	oberon_assert_token(ctx, COLON);
+
+	oberon_type_t * type;
+	type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+	oberon_type(ctx, &type);
+
+	oberon_object_t * first;
+	first = oberon_make_param(ctx, modifer_token, name, type);
+
+	*num_decl += 1;
+	return first;
+}
+
+#define ISFPSECTION \
+	((ctx -> token == VAR) || (ctx -> token == IDENT))
+
+static void
+oberon_formal_pars(oberon_context_t * ctx, oberon_type_t * signature)
+{
+	oberon_assert_token(ctx, LPAREN);
+
+	if(ISFPSECTION)
+	{
+		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);
+		}
+	}
+
+	oberon_assert_token(ctx, RPAREN);
+
+	if(ctx -> token == COLON)
+	{
+		oberon_assert_token(ctx, COLON);
+		// TODO get by qualident
+		oberon_type(ctx, &signature -> base);
+	}
+}
+
+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);
+	}
+}
+
+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_error(ctx, "number parameters not matched");
+	}
+
+	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++)
+	{
+		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
+	{
+		if(expr == NULL)
+		{
+			oberon_error(ctx, "procedure requires expression on result");
+		}
+
+		oberon_autocast_to(ctx, expr, result_type);
+	}
+
+	proc -> has_return = 1;
+
+	oberon_generate_return(ctx, expr);
+}
+
+static void
+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);
+	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 void
+oberon_proc_decl(oberon_context_t * ctx)
+{
+	oberon_assert_token(ctx, PROCEDURE);
+
+	int forward = 0;
+	if(ctx -> token == UPARROW)
+	{
+		oberon_assert_token(ctx, UPARROW);
+		forward = 1;
+	}
+
+	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)
+	{
+		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
+	{
+		proc = oberon_define_object(ctx -> decl, name, OBERON_CLASS_PROC);
+		proc -> type = signature;
+		proc -> scope = proc_scope;
+		oberon_generator_init_proc(ctx, proc);
+	}
+
+	proc -> scope -> parent = proc;
+
+	if(forward == 0)
+	{
+		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);
+
+	constant = oberon_define_object(ctx -> decl, name, OBERON_CLASS_CONST);
+	constant -> value = value;
+}
+
+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");
+	}
+
+	if(size -> item.mode != MODE_INTEGER)
+	{
+		oberon_error(ctx, "requires integer constant");
+	}
+
+	oberon_type_t * arr;
+	arr = *type;
+	arr -> class = OBERON_TYPE_ARRAY;
+	arr -> size = size -> item.integer;
+	arr -> base = base;
+}
+
+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);
+
+		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)
+{
+	char * name;
+	oberon_object_t * to;
+
+	name = oberon_assert_ident(ctx);
+	to = oberon_find_object(ctx -> decl, name, 0);
+
+	if(to != NULL)
+	{
+		if(to -> class != OBERON_CLASS_TYPE)
+		{
+			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);
+	}
+
+	*type = to -> type;
+}
+
+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)
+	{
+		*type = base;
+		return;
+	}
+
+	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 void
+oberon_type(oberon_context_t * ctx, oberon_type_t ** type)
+{
+	if(ctx -> token == IDENT)
+	{
+		oberon_qualident_type(ctx, type);
+	}
+	else if(ctx -> token == ARRAY)
+	{
+		oberon_assert_token(ctx, ARRAY);
+
+		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)
+	{
+		oberon_open_scope(ctx);
+		oberon_assert_token(ctx, PROCEDURE);
+		oberon_opt_formal_pars(ctx, type);
+		oberon_close_scope(ctx -> decl);
+	}
+	else
+	{
+		oberon_error(ctx, "invalid type declaration");
+	}
+}
+
+static void
+oberon_type_decl(oberon_context_t * ctx)
+{
+	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)
+	{
+		newtype = oberon_define_object(ctx -> decl, name, OBERON_CLASS_TYPE);
+		newtype -> type = oberon_new_type_ptr(OBERON_TYPE_VOID);
+		assert(newtype -> type);
+	}
+	else
+	{
+		if(newtype -> class != OBERON_CLASS_TYPE)
+		{
+			oberon_error(ctx, "mult definition");
+		}
+
+		if(newtype -> linked)
+		{
+			oberon_error(ctx, "mult definition - already linked");
+		}
+	}
+
+	oberon_assert_token(ctx, EQUAL);
+
+	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);
 
-#define ISADDOP(x) \
-	((x) >= PLUS && (x) <= OR)
+	type -> recursive = 0;
+}
 
-static oberon_expr_t *
-oberon_simple_expr(oberon_context_t * ctx)
+static void
+oberon_prevent_recursive_record(oberon_context_t * ctx, oberon_type_t * type)
 {
-	oberon_expr_t * expr;
+	if(type -> class != OBERON_TYPE_RECORD)
+	{
+		return;
+	}
 
-	int minus = 0;
-	if(ctx -> token == PLUS)
+	if(type -> recursive)
 	{
-		minus = 0;
-		oberon_assert_token(ctx, PLUS);
+		oberon_error(ctx, "recursive record declaration");
 	}
-	else if(ctx -> token == MINUS)
+
+	type -> recursive = 1;
+
+	int num_fields = type -> num_decl;
+	oberon_object_t * field = type -> decl;
+	for(int i = 0; i < num_fields; i++)
 	{
-		minus = 1;
-		oberon_assert_token(ctx, MINUS);
+		oberon_prevent_recursive_object(ctx, field);
+		field = field -> next;
 	}
 
-	expr = oberon_term_expr(ctx);
-	while(ISADDOP(ctx -> token))
+	type -> recursive = 0;	
+}
+static void
+oberon_prevent_recursive_procedure(oberon_context_t * ctx, oberon_type_t * type)
+{
+	if(type -> class != OBERON_TYPE_PROCEDURE)
 	{
-		int token = ctx -> token;
-		oberon_read_token(ctx);
+		return;
+	}
 
-		oberon_expr_t * inter = oberon_term_expr(ctx);
-		expr = oberon_make_bin_op(ctx, token, expr, inter);
+	if(type -> recursive)
+	{
+		oberon_error(ctx, "recursive procedure declaration");
 	}
 
-	if(minus)
+	type -> recursive = 1;
+
+	int num_fields = type -> num_decl;
+	oberon_object_t * field = type -> decl;
+	for(int i = 0; i < num_fields; i++)
 	{
-		expr = oberon_make_unary_op(ctx, MINUS, expr);
+		oberon_prevent_recursive_object(ctx, field);
+		field = field -> next;
 	}
 
-	return expr;
+	type -> recursive = 0;	
 }
 
-#define ISRELATION(x) \
-	((x) >= EQUAL && (x) <= GEQ)
-
-static oberon_expr_t *
-oberon_expr(oberon_context_t * ctx)
+static void
+oberon_prevent_recursive_array(oberon_context_t * ctx, oberon_type_t * type)
 {
-	oberon_expr_t * expr;
-
-	expr = oberon_simple_expr(ctx);
-	while(ISRELATION(ctx -> token))
+	if(type -> class != OBERON_TYPE_ARRAY)
 	{
-		int token = ctx -> token;
-		oberon_read_token(ctx);
+		return;
+	}
 
-		oberon_expr_t * inter = oberon_simple_expr(ctx);
-		expr = oberon_make_bin_op(ctx, token, expr, inter);
+	if(type -> recursive)
+	{
+		oberon_error(ctx, "recursive array declaration");
 	}
 
-	return expr;
-}
+	type -> recursive = 1;
 
-// =======================================================================
-//   PARSER
-// =======================================================================
+	oberon_prevent_recursive_type(ctx, type -> base);
 
-static void oberon_statement_seq(oberon_context_t * ctx);
+	type -> recursive = 0;
+}
 
 static void
-oberon_expect_token(oberon_context_t * ctx, int token)
+oberon_prevent_recursive_type(oberon_context_t * ctx, oberon_type_t * type)
 {
-	if(ctx -> token != token)
+	if(type -> class == OBERON_TYPE_POINTER)
 	{
-		oberon_error(ctx, "unexpected token %i (%i)", ctx -> token, token);
+		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);
 	}
 }
 
 static void
-oberon_assert_token(oberon_context_t * ctx, int token)
+oberon_prevent_recursive_object(oberon_context_t * ctx, oberon_object_t * x)
 {
-	oberon_expect_token(ctx, token);
-	oberon_read_token(ctx);
+	switch(x -> class)
+	{
+		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:
+			break;
+		default:
+			oberon_error(ctx, "oberon_prevent_recursive_object: wat");
+			break;
+	}
 }
 
-static char *
-oberon_assert_ident(oberon_context_t * ctx)
+static void
+oberon_prevent_recursive_decl(oberon_context_t * ctx)
 {
-	oberon_expect_token(ctx, IDENT);
-	char * ident = ctx -> string;
-	oberon_read_token(ctx);
-	return ident;
-}
+	oberon_object_t * x = ctx -> decl -> list -> next;
 
-static oberon_type_t *
-oberon_type(oberon_context_t * ctx)
-{
-	char * name = oberon_assert_ident(ctx);
-	oberon_type_t * type = oberon_find_type(ctx -> decl, name);
-	return type;
+	while(x)
+	{
+		oberon_prevent_recursive_object(ctx, x);
+		x = x -> next;
+	}
 }
 
-static void
-oberon_var_decl(oberon_context_t * ctx)
-{
-	char * name = oberon_assert_ident(ctx);
-	oberon_assert_token(ctx, COLON);
-	oberon_type_t * type = oberon_type(ctx);
-	oberon_define_var(ctx -> decl, name, type);
-}
+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_make_procedure_begin(oberon_context_t * ctx, char * name)
+oberon_initialize_record_fields(oberon_context_t * ctx, oberon_type_t * type)
 {
-	oberon_object_t * proc;
-	proc = oberon_define_proc(ctx -> decl, name);
-
-	oberon_open_scope(ctx);
+	if(type -> class != OBERON_TYPE_RECORD)
+	{
+		return;
+	}
 
-	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++)
+	{
+		if(field -> type -> class == OBERON_TYPE_POINTER)
+		{
+			oberon_initialize_type(ctx, field -> type);
+		}
 
-static void
-oberon_make_procedure_end(oberon_context_t * ctx)
-{
-	oberon_generate_end_proc(ctx);
+		oberon_initialize_object(ctx, field);
+		field = field -> next;
+	}
 
-	oberon_close_scope(ctx -> decl);
+	oberon_generator_init_record(ctx, type);
 }
 
 static void
-oberon_proc_decl(oberon_context_t * ctx)
+oberon_initialize_type(oberon_context_t * ctx, oberon_type_t * type)
 {
-	oberon_assert_token(ctx, PROCEDURE);
+	if(type -> class == OBERON_TYPE_VOID)
+	{
+		oberon_error(ctx, "undeclarated type");
+	}
 
-	char * name;
-	name = oberon_assert_ident(ctx);
+	if(type -> initialized)
+	{
+		return;
+	}
 
-	oberon_assert_token(ctx, SEMICOLON);
+	type -> initialized = 1;
 
-	oberon_make_procedure_begin(ctx, name);
-	if(ctx -> token == BEGIN)
+	if(type -> class == OBERON_TYPE_POINTER)
 	{
-		oberon_assert_token(ctx, BEGIN);
-		oberon_statement_seq(ctx);
+		oberon_initialize_type(ctx, type -> base);
+		oberon_generator_init_type(ctx, type);
 	}
-	oberon_make_procedure_end(ctx);
-
-	oberon_assert_token(ctx, END);
-	char * name2 = oberon_assert_ident(ctx);
+	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;
+		}		
 
-	if(strcmp(name2, name) != 0)
+		oberon_generator_init_type(ctx, type);
+	}
+	else
 	{
-		oberon_error(ctx, "procedure name not matched");
+		oberon_generator_init_type(ctx, type);
 	}
 }
 
 static void
-oberon_decl_seq(oberon_context_t * ctx)
+oberon_initialize_object(oberon_context_t * ctx, oberon_object_t * x)
 {
-	if(ctx -> token == VAR)
+	if(x -> initialized)
 	{
-		oberon_assert_token(ctx, VAR);
-		while(ctx -> token == IDENT)
-		{
-			oberon_var_decl(ctx);
-			oberon_assert_token(ctx, SEMICOLON);
-		}
+		return;
 	}
 
-	if(ctx -> token == PROCEDURE)
+	x -> initialized = 1;
+
+	switch(x -> class)
 	{
-		oberon_proc_decl(ctx);
-		oberon_assert_token(ctx, SEMICOLON);
+		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:
+			break;
+		default:
+			oberon_error(ctx, "oberon_prevent_recursive_object: wat");
+			break;
 	}
 }
 
 static void
-oberon_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
+oberon_initialize_decl(oberon_context_t * ctx)
 {
-	if(src -> result -> class != dst -> result -> class)
+	oberon_object_t * x = ctx -> decl -> list;
+
+	while(x -> next)
 	{
-		oberon_error(ctx, "incompatible assignment types");
-	}
+		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;
 
-	if(dst -> result -> class == OBERON_TYPE_INTEGER)
+	while(x -> next)
 	{
-		if((dst -> result -> size) < (src -> result -> size))
+		if(x -> next -> class == OBERON_CLASS_PROC)
 		{
-			oberon_error(ctx, "incompatible assignment type size");
+			if(x -> next -> linked == 0)
+			{
+				oberon_error(ctx, "unresolved forward declaration");
+			}
 		}
-	}
-
-	oberon_generate_assign(ctx, src, dst);
+		x = x -> next;
+	}	
 }
 
 static void
-oberon_make_call(oberon_context_t * ctx, oberon_expr_t * desig)
+oberon_decl_seq(oberon_context_t * ctx)
 {
-	if(desig -> is_item == 0)
+	if(ctx -> token == CONST)
 	{
-		oberon_error(ctx, "expected item");
+		oberon_assert_token(ctx, CONST);
+		while(ctx -> token == IDENT)
+		{
+			oberon_const_decl(ctx);
+			oberon_assert_token(ctx, SEMICOLON);
+		}
 	}
 
-	if(desig -> item.mode != MODE_CALL)
+	if(ctx -> token == TYPE)
 	{
-		oberon_error(ctx, "expected mode CALL");
+		oberon_assert_token(ctx, TYPE);
+		while(ctx -> token == IDENT)
+		{
+			oberon_type_decl(ctx);
+			oberon_assert_token(ctx, SEMICOLON);
+		}
 	}
 
-	if(desig -> item.var -> class != OBERON_CLASS_PROC)
+	if(ctx -> token == VAR)
 	{
-		oberon_error(ctx, "only procedures can be called");
+		oberon_assert_token(ctx, VAR);
+		while(ctx -> token == IDENT)
+		{
+			oberon_var_decl(ctx);
+			oberon_assert_token(ctx, SEMICOLON);
+		}
+	}
+
+	oberon_prevent_recursive_decl(ctx);
+	oberon_initialize_decl(ctx);
+
+	while(ctx -> token == PROCEDURE)
+	{
+		oberon_proc_decl(ctx);
+		oberon_assert_token(ctx, SEMICOLON);
 	}
 
-	// TODO check arguments
+	oberon_prevent_undeclarated_procedures(ctx);
+}
 
-	oberon_generate_call_proc(ctx, desig);
+static void
+oberon_assign(oberon_context_t * ctx, oberon_expr_t * src, oberon_expr_t * dst)
+{
+	oberon_autocast_to(ctx, src, dst -> result);
+	oberon_generate_assign(ctx, src, dst);
 }
 
 static void
@@ -943,7 +2211,7 @@ oberon_statement(oberon_context_t * ctx)
 
 	if(ctx -> token == IDENT)
 	{
-		item1 = oberon_expr(ctx);
+		item1 = oberon_designator(ctx);
 		if(ctx -> token == ASSIGN)
 		{
 			oberon_assert_token(ctx, ASSIGN);
@@ -952,7 +2220,21 @@ oberon_statement(oberon_context_t * ctx)
 		}
 		else
 		{
-			oberon_make_call(ctx, item1);
+			oberon_opt_proc_parens(ctx, item1);
+		}
+	}
+	else if(ctx -> token == RETURN)
+	{
+		oberon_assert_token(ctx, RETURN);
+		if(ISEXPR(ctx -> token))
+		{
+			oberon_expr_t * expr;
+			expr = oberon_expr(ctx);
+			oberon_make_return(ctx, expr);
+		}
+		else
+		{
+			oberon_make_return(ctx, NULL);
 		}
 	}
 }
@@ -1003,41 +2285,73 @@ oberon_parse_module(oberon_context_t * ctx)
 //   LIBRARY
 // =======================================================================
 
-static oberon_type_t *
-oberon_new_type_ptr(int class)
+static void
+register_default_types(oberon_context_t * ctx)
 {
-	oberon_type_t * x = malloc(sizeof *x);
-	memset(x, 0, sizeof *x);
-	x -> class = class;
-	return x;
+	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);
+
+	ctx -> bool_type = oberon_new_type_boolean(sizeof(int));
+	oberon_define_type(ctx -> world_scope, "BOOLEAN", ctx -> bool_type);
 }
 
-static oberon_type_t *
-oberon_new_type_integer(int size)
+static void
+oberon_new_intrinsic_function(oberon_context_t * ctx, char * name, GenerateFuncCallback generate)
 {
-	oberon_type_t * x;
-	x = oberon_new_type_ptr(OBERON_TYPE_INTEGER);
-	x -> size = size;
-	return x;
+	oberon_object_t * proc;
+	proc = oberon_define_object(ctx -> decl, name, OBERON_CLASS_PROC);
+	proc -> sysproc = 1;
+	proc -> genfunc = generate;
+	proc -> type = oberon_new_type_ptr(OBERON_TYPE_PROCEDURE);
 }
 
-static oberon_type_t *
-oberon_new_type_boolean(int size)
+/*
+static void
+oberon_new_intrinsic_procedure(oberon_context_t * ctx, char * name, GenerateProcCallback generate)
 {
-	oberon_type_t * x;
-	x = oberon_new_type_ptr(OBERON_TYPE_BOOLEAN);
-	x -> size = size;
-	return x;
+	oberon_object_t * proc;
+	proc = oberon_define_object(ctx -> decl, name, OBERON_CLASS_PROC);
+	proc -> sysproc = 1;
+	proc -> genproc = generate;
+	proc -> type = oberon_new_type_ptr(OBERON_TYPE_PROCEDURE);
 }
+*/
 
-static void
-register_default_types(oberon_context_t * ctx)
+static oberon_expr_t *
+oberon_make_abs_call(oberon_context_t * ctx, int num_args, oberon_expr_t * list_args)
 {
-	ctx -> int_type = oberon_new_type_integer(sizeof(int));
-	ctx -> bool_type = oberon_new_type_boolean(sizeof(int));
+	if(num_args < 1)
+	{
+		oberon_error(ctx, "too few arguments");
+	}
 
-	oberon_define_type(ctx -> world_scope, "INTEGER", ctx -> int_type);
-	oberon_define_type(ctx -> world_scope, "BOOLEAN", ctx -> bool_type);
+	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 *
@@ -1052,7 +2366,8 @@ oberon_create_context()
 
 	oberon_generator_init_context(ctx);
 
-	register_default_types(ctx);	
+	register_default_types(ctx);
+	oberon_new_intrinsic_function(ctx, "ABS", oberon_make_abs_call);
 
 	return ctx;
 }