diff -r 0c2ef191b22a -r d48f53715f77 stage3/datatype_functions.hh
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stage3/datatype_functions.hh	Wed Feb 01 19:49:11 2012 +0000
@@ -0,0 +1,111 @@
+/*
+ *  matiec - a compiler for the programming languages defined in IEC 61131-3
+ *
+ *  Copyright (C) 2009-2012  Mario de Sousa (msousa@fe.up.pt)
+ *  Copyright (C) 2012       Manuele Conti  (conti.ma@alice.it)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * This code is made available on the understanding that it will not be
+ * used in safety-critical situations without a full and competent review.
+ */
+
+#ifndef _HELPER_FUNCTIONS_HH_
+#define _HELPER_FUNCTIONS_HH_
+
+#include "../absyntax/visitor.hh"
+#include <typeinfo>
+
+#define is_type(type_name_symbol, type_name_class)  ((type_name_symbol == NULL) ? false : (typeid(*type_name_symbol) == typeid(type_name_class)))
+#define sizeoftype(symbol) get_sizeof_datatype_c::getsize(symbol)
+
+/* Widening Primitive Conversion */
+struct widen_entry {
+	symbol_c *left;
+	symbol_c *right;
+	symbol_c *result;
+};
+/*
+ * 2.5.1.5.6 Functions of time data types
+ * Table 30 - page 64
+ */
+extern const struct widen_entry widen_ADD_table[];
+extern const struct widen_entry widen_SUB_table[];
+extern const struct widen_entry widen_MUL_table[];
+extern const struct widen_entry widen_DIV_table[];
+
+/* A helper function... */
+bool is_ANY_ELEMENTARY_type         (symbol_c *type_symbol);
+bool is_ANY_SAFEELEMENTARY_type     (symbol_c *type_symbol);
+bool is_ANY_ELEMENTARY_compatible   (symbol_c *type_symbol);
+
+bool is_ANY_MAGNITUDE_type          (symbol_c *type_symbol);
+bool is_ANY_SAFEMAGNITUDE_type      (symbol_c *type_symbol);
+bool is_ANY_MAGNITUDE_compatible    (symbol_c *type_symbol);
+
+bool is_ANY_DATE_type               (symbol_c *type_symbol);
+bool is_ANY_SAFEDATE_type           (symbol_c *type_symbol);
+bool is_ANY_DATE_compatible         (symbol_c *type_symbol);
+
+bool is_ANY_STRING_type             (symbol_c *type_symbol);
+bool is_ANY_SAFESTRING_type         (symbol_c *type_symbol);
+bool is_ANY_STRING_compatible       (symbol_c *type_symbol);
+
+bool is_ANY_INT_type                (symbol_c *type_symbol);
+bool is_ANY_SAFEINT_type            (symbol_c *type_symbol);
+bool is_ANY_INT_compatible          (symbol_c *type_symbol);
+
+bool is_ANY_REAL_type               (symbol_c *type_symbol);
+bool is_ANY_SAFEREAL_type           (symbol_c *type_symbol);
+bool is_ANY_REAL_compatible         (symbol_c *type_symbol);
+
+bool is_ANY_NUM_type                (symbol_c *type_symbol);
+bool is_ANY_SAFENUM_type            (symbol_c *type_symbol);
+bool is_ANY_NUM_compatible          (symbol_c *type_symbol);
+
+bool is_ANY_BIT_type                (symbol_c *type_symbol);
+bool is_ANY_SAFEBIT_type            (symbol_c *type_symbol);
+bool is_ANY_BIT_compatible          (symbol_c *type_symbol);
+
+bool is_BOOL_type                   (symbol_c *type_symbol);
+bool is_SAFEBOOL_type               (symbol_c *type_symbol);
+bool is_ANY_BOOL_compatible         (symbol_c *type_symbol);
+
+bool is_nonneg_literal_integer_type (symbol_c *type_symbol);
+bool is_literal_integer_type        (symbol_c *type_symbol);
+bool is_literal_real_type           (symbol_c *type_symbol);
+bool is_literal_bool_type           (symbol_c *type_symbol);
+
+/* Determine the common data type between two data types.
+ * If no common data type found, return NULL.
+ *
+ * If data types are identical, return the first (any would do...).
+ * If any of the data types is a literal, we confirm that
+ *   the literal uses less bits than the fixed size data type.
+ *   e.g. BYTE and 1024 returns NULL
+ *        BYTE and 255  returns BYTE
+ *
+ * If two literals, then return the literal that requires more bits...
+ */
+symbol_c *common_type(symbol_c *first_type, symbol_c *second_type);
+bool is_valid_assignment(symbol_c *var_type, symbol_c *value_type);
+bool is_compatible_type(symbol_c *first_type, symbol_c *second_type);
+bool is_type_equal(symbol_c *first_type, symbol_c *second_type);
+
+typedef bool (*helper_function_t) (symbol_c *type_symbol);  /* a pointer to a function! */
+
+
+
+#endif /* _HELPER_FUNCTIONS_HH_ */