diff -r 0c2ef191b22a -r d48f53715f77 stage3/datatype_functions.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stage3/datatype_functions.cc	Wed Feb 01 19:49:11 2012 +0000
@@ -0,0 +1,620 @@
+/*
+ *  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.
+ */
+
+#include "datatype_functions.hh"
+#include "../absyntax_utils/absyntax_utils.hh"
+
+/*
+ * 2.5.1.5.6 Functions of time data types
+ * Table 30 - page 64
+ */
+
+const struct widen_entry widen_ADD_table[] = {
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::time_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::tod_type_name,             &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::dt_type_name,              &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::safetod_type_name,         &search_constant_type_c::safetod_type_name  },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::safedt_type_name,          &search_constant_type_c::safedt_type_name   },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::time_type_name,            &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::time_type_name,            &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::safetime_type_name,        &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safetod_type_name  },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::time_type_name,            &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::time_type_name,            &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::safetime_type_name,        &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safedt_type_name   },
+    { NULL, NULL, NULL },
+};
+
+
+const struct widen_entry widen_SUB_table[] = {
+	{ &search_constant_type_c::time_type_name,          &search_constant_type_c::time_type_name,            &search_constant_type_c::time_type_name     },
+	{ &search_constant_type_c::tod_type_name,           &search_constant_type_c::tod_type_name,             &search_constant_type_c::tod_type_name      },
+	{ &search_constant_type_c::dt_type_name,            &search_constant_type_c::dt_type_name,              &search_constant_type_c::dt_type_name       },
+	{ &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safetime_type_name },
+	{ &search_constant_type_c::safetod_type_name,       &search_constant_type_c::safetod_type_name,         &search_constant_type_c::safetod_type_name  },
+	{ &search_constant_type_c::safedt_type_name,        &search_constant_type_c::safedt_type_name,          &search_constant_type_c::safedt_type_name   },
+
+	{ &search_constant_type_c::tod_type_name,           &search_constant_type_c::time_type_name,            &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::time_type_name,            &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::safetime_type_name,        &search_constant_type_c::tod_type_name      },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safetod_type_name  },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::time_type_name,            &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::time_type_name,            &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::safetime_type_name,        &search_constant_type_c::dt_type_name       },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::safetime_type_name,        &search_constant_type_c::safedt_type_name   },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::tod_type_name,             &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::tod_type_name,             &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::tod_type_name,           &search_constant_type_c::safetod_type_name,         &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safetod_type_name,       &search_constant_type_c::safetod_type_name,         &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::date_type_name,          &search_constant_type_c::date_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safedate_type_name,      &search_constant_type_c::date_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::date_type_name,          &search_constant_type_c::safedate_type_name,        &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safedate_type_name,      &search_constant_type_c::safedate_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::dt_type_name,              &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::dt_type_name,              &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::dt_type_name,            &search_constant_type_c::safedt_type_name,          &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::safedt_type_name,        &search_constant_type_c::safedt_type_name,          &search_constant_type_c::safetime_type_name },
+    { NULL, NULL, NULL },
+};
+
+const struct widen_entry widen_MUL_table[] = {
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::lreal_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::real_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::dint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::int_type_name,             &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::sint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::ulint_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::udint_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::uint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::usint_type_name,           &search_constant_type_c::time_type_name     },
+
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::lreal_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::real_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::dint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::int_type_name,             &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::sint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::ulint_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::udint_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::uint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::usint_type_name,           &search_constant_type_c::safetime_type_name },
+
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safelreal_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safereal_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safedint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeint_type_name,         &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safesint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeulint_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeudint_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeuint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeusint_type_name,       &search_constant_type_c::safetime_type_name },
+
+    { NULL, NULL, NULL },
+};
+
+const struct widen_entry widen_DIV_table[] = {
+	{ &search_constant_type_c::time_type_name,          &search_constant_type_c::lreal_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::real_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::dint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::int_type_name,             &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::sint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::ulint_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::udint_type_name,           &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::uint_type_name,            &search_constant_type_c::time_type_name     },
+    { &search_constant_type_c::time_type_name,          &search_constant_type_c::usint_type_name,           &search_constant_type_c::time_type_name     },
+
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::lreal_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::real_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::dint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::int_type_name,             &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::sint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::ulint_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::udint_type_name,           &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::uint_type_name,            &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::usint_type_name,           &search_constant_type_c::safetime_type_name },
+
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safelreal_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safereal_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safedint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeint_type_name,         &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safesint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeulint_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeudint_type_name,       &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeuint_type_name,        &search_constant_type_c::safetime_type_name },
+    { &search_constant_type_c::safetime_type_name,      &search_constant_type_c::safeusint_type_name,       &search_constant_type_c::safetime_type_name },
+
+    { NULL, NULL, NULL },
+};
+
+/* NOTE on data type handling and literals...
+ * ==========================================
+ *
+ * Literals that are explicitly type cast
+ *   e.g.:   BYTE#42
+ *           INT#65
+ *           TIME#45h23m
+ *               etc...
+ *  are NOT considered literals in the following code.
+ *  Since they are type cast, and their data type is fixed and well known,
+ *  they are treated as a variable of that data type (except when determining lvalues)
+ *  In other words, when calling search_constant_type_c on these constants, it returns
+ *  a xxxxx_type_name_c, and not one of the xxxx_literal_c !
+ *
+ *  When the following code handles a literal, it is really a literal of unknown data type.
+ *    e.g.   42, may be considered an int, a byte, a word, etc...
+ *
+ * NOTE: type_symbol == NULL is valid!
+ *       This will occur, for example, when and undefined/undeclared symbolic_variable is used in the program.
+ *       This will not be of any type, so we always return false.
+ */
+
+/* A helper function... */
+bool is_ANY_ELEMENTARY_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  return is_ANY_MAGNITUDE_type(type_symbol)
+      || is_ANY_BIT_type      (type_symbol)
+      || is_ANY_STRING_type   (type_symbol)
+      || is_ANY_DATE_type     (type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_SAFEELEMENTARY_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  return is_ANY_SAFEMAGNITUDE_type(type_symbol)
+      || is_ANY_SAFEBIT_type      (type_symbol)
+      || is_ANY_SAFESTRING_type   (type_symbol)
+      || is_ANY_SAFEDATE_type     (type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_ELEMENTARY_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  /* NOTE: doing
+   *          return is_ANY_SAFEELEMENTARY_type() || is_ANY_ELEMENTARY_type()
+   *       is incorrect, as the literals would never be considered compatible...
+   */
+  return is_ANY_MAGNITUDE_compatible(type_symbol)
+      || is_ANY_BIT_compatible      (type_symbol)
+      || is_ANY_STRING_compatible   (type_symbol)
+      || is_ANY_DATE_compatible     (type_symbol);
+}
+
+
+/* A helper function... */
+bool is_ANY_MAGNITUDE_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(time_type_name_c)) {return true;}
+  return is_ANY_NUM_type(type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_SAFEMAGNITUDE_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safetime_type_name_c)) {return true;}
+  return is_ANY_SAFENUM_type(type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_MAGNITUDE_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_MAGNITUDE_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFEMAGNITUDE_type(type_symbol))              {return true;}
+
+  return is_ANY_NUM_compatible(type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_NUM_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_REAL_type(type_symbol))                       {return true;}
+  if (is_ANY_INT_type(type_symbol))                        {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFENUM_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  return is_ANY_SAFEREAL_type(type_symbol)
+      || is_ANY_SAFEINT_type (type_symbol);
+}
+
+/* A helper function... */
+bool is_ANY_NUM_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_REAL_compatible(type_symbol))                       {return true;}
+  if (is_ANY_INT_compatible(type_symbol))                        {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_DATE_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(date_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(tod_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(dt_type_name_c))   {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFEDATE_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safedate_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(safetod_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safedt_type_name_c))   {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_DATE_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_DATE_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFEDATE_type(type_symbol))              {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_STRING_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(string_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(wstring_type_name_c)) {return true;}
+// TODO literal_string ???
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFESTRING_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safestring_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(safewstring_type_name_c)) {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_STRING_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_STRING_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFESTRING_type(type_symbol))              {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_INT_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(sint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(int_type_name_c))   {return true;}
+  if (typeid(*type_symbol) == typeid(dint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(lint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(usint_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(uint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(udint_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(ulint_type_name_c)) {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFEINT_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safesint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safeint_type_name_c))   {return true;}
+  if (typeid(*type_symbol) == typeid(safedint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safelint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safeusint_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(safeuint_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safeudint_type_name_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(safeulint_type_name_c)) {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_INT_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_INT_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFEINT_type(type_symbol))              {return true;}
+  if (is_literal_integer_type(type_symbol))          {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_REAL_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(real_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(lreal_type_name_c)) {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFEREAL_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safereal_type_name_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(safelreal_type_name_c)) {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_REAL_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_REAL_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFEREAL_type(type_symbol))              {return true;}
+  if (is_literal_real_type(type_symbol))              {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_BIT_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(bool_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(byte_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(word_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(dword_type_name_c))    {return true;}
+  if (typeid(*type_symbol) == typeid(lword_type_name_c))    {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_SAFEBIT_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safebool_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(safebyte_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(safeword_type_name_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(safedword_type_name_c))    {return true;}
+  if (typeid(*type_symbol) == typeid(safelword_type_name_c))    {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_BIT_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_ANY_BIT_type    (type_symbol))              {return true;}
+  if (is_ANY_SAFEBIT_type(type_symbol))              {return true;}
+  if (is_nonneg_literal_integer_type(type_symbol))   {return true;}
+  if (is_literal_bool_type(type_symbol))             {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_BOOL_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(bool_type_name_c))      {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_SAFEBOOL_type(symbol_c *type_symbol){
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(safebool_type_name_c))  {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_ANY_BOOL_compatible(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (is_BOOL_type    (type_symbol))              {return true;}
+  if (is_SAFEBOOL_type(type_symbol))              {return true;}
+  if (is_literal_bool_type(type_symbol))              {return true;}
+  return false;
+}
+
+/* A helper function... */
+bool is_literal_integer_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(neg_integer_c))        {return true;}
+  return is_nonneg_literal_integer_type(type_symbol);
+}
+
+
+/* A helper function... */
+bool is_nonneg_literal_integer_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(integer_c))        {return true;}
+  if (typeid(*type_symbol) == typeid(binary_integer_c)) {return true;}
+  if (typeid(*type_symbol) == typeid(octal_integer_c))  {return true;}
+  if (typeid(*type_symbol) == typeid(hex_integer_c))    {return true;}
+  return false;
+}
+
+
+/* A helper function... */
+bool is_literal_real_type(symbol_c *type_symbol) {
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(real_c))     {return true;}
+  if (typeid(*type_symbol) == typeid(neg_real_c)) {return true;}
+  return false;
+}
+
+
+/* A helper function... */
+bool is_literal_bool_type(symbol_c *type_symbol) {
+  bool_type_name_c bool_t;
+
+  if (type_symbol == NULL) {return false;}
+  if (typeid(*type_symbol) == typeid(boolean_true_c))    {return true;}
+  if (typeid(*type_symbol) == typeid(boolean_false_c))   {return true;}
+  if (is_nonneg_literal_integer_type(type_symbol))
+    if (sizeoftype(&bool_t) >= sizeoftype(type_symbol))  {return true;}
+  return false;
+}
+
+/* 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 (actually 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) {
+  if (first_type == NULL && second_type == NULL) {return NULL;}
+  if (first_type == NULL)  {return second_type;}
+  if (second_type == NULL) {return first_type;}
+
+  if (is_literal_integer_type(first_type) && is_literal_integer_type(second_type))
+    {return ((sizeoftype(first_type) > sizeoftype(second_type))? first_type:second_type);}
+
+  if (is_literal_real_type(first_type) && is_literal_real_type(second_type))
+    {return ((sizeoftype(first_type) > sizeoftype(second_type))? first_type:second_type);}
+
+  if (is_literal_bool_type(first_type) && is_literal_bool_type(second_type))
+    {return first_type;}
+
+  /* The following check can only be made after the is_literal_XXXX checks */
+  /* When two literals of the same type, with identical typeid's are checked,
+   * we must return the one that occupies more bits... This is done above.
+   */
+  if (typeid(*first_type) == typeid(*second_type)) {return first_type;}
+
+  /* NOTE Although a BOOL is also an ANY_BIT, we must check it explicitly since some
+   *       literal bool values are not literal integers...
+   */
+  if (is_BOOL_type(first_type)        && is_literal_bool_type(second_type))    {return first_type;}
+  if (is_BOOL_type(second_type)       && is_literal_bool_type(first_type))     {return second_type;}
+
+  if (is_SAFEBOOL_type(first_type)    && is_literal_bool_type(second_type))    {return first_type;}
+  if (is_SAFEBOOL_type(second_type)   && is_literal_bool_type(first_type))     {return second_type;}
+
+  if (is_SAFEBOOL_type(first_type)    && is_BOOL_type(second_type))            {return second_type;}
+  if (is_SAFEBOOL_type(second_type)   && is_BOOL_type(first_type))             {return first_type;}
+
+  if (is_ANY_BIT_type(first_type)     && is_nonneg_literal_integer_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_BIT_type(second_type)    && is_nonneg_literal_integer_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if (is_ANY_SAFEBIT_type(first_type)     && is_nonneg_literal_integer_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_SAFEBIT_type(second_type)    && is_nonneg_literal_integer_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if  (is_ANY_SAFEBIT_type(first_type)    && is_ANY_BIT_type(second_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? second_type:NULL);}
+  if  (is_ANY_SAFEBIT_type(second_type)   && is_ANY_BIT_type(first_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? first_type :NULL);}
+
+  if (is_ANY_INT_type(first_type)     && is_literal_integer_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_INT_type(second_type)    && is_literal_integer_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if (is_ANY_SAFEINT_type(first_type)     && is_literal_integer_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_SAFEINT_type(second_type)    && is_literal_integer_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if  (is_ANY_SAFEINT_type(first_type)    && is_ANY_INT_type(second_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? second_type:NULL);}
+  if  (is_ANY_SAFEINT_type(second_type)   && is_ANY_INT_type(first_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? first_type :NULL);}
+
+  if (is_ANY_REAL_type(first_type)    && is_literal_real_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_REAL_type(second_type)   && is_literal_real_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if (is_ANY_SAFEREAL_type(first_type)    && is_literal_real_type(second_type))
+    {return ((sizeoftype(first_type)  >= sizeoftype(second_type))? first_type :NULL);}
+  if (is_ANY_SAFEREAL_type(second_type)   && is_literal_real_type(first_type))
+    {return ((sizeoftype(second_type) >= sizeoftype(first_type)) ? second_type:NULL);}
+
+  if  (is_ANY_SAFEREAL_type(first_type)    && is_ANY_REAL_type(second_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? second_type:NULL);}
+  if  (is_ANY_SAFEREAL_type(second_type)   && is_ANY_REAL_type(first_type))
+    {return ((sizeoftype(first_type) == sizeoftype(second_type))? first_type :NULL);}
+
+  /* the Time and Date types... */
+  if (is_type(first_type,  safetime_type_name_c) && is_type(second_type, time_type_name_c))  {return second_type;}
+  if (is_type(second_type, safetime_type_name_c) && is_type( first_type, time_type_name_c))  {return  first_type;}
+
+  if (is_type(first_type,  safedate_type_name_c) && is_type(second_type, date_type_name_c))  {return second_type;}
+  if (is_type(second_type, safedate_type_name_c) && is_type( first_type, date_type_name_c))  {return  first_type;}
+
+  if (is_type(first_type,  safedt_type_name_c)   && is_type(second_type, dt_type_name_c))    {return second_type;}
+  if (is_type(second_type, safedt_type_name_c)   && is_type( first_type, dt_type_name_c))    {return  first_type;}
+
+  if (is_type(first_type,  safetod_type_name_c)  && is_type(second_type, tod_type_name_c))   {return second_type;}
+  if (is_type(second_type, safetod_type_name_c)  && is_type( first_type, tod_type_name_c))   {return  first_type;}
+
+  /* no common type */
+  return NULL;
+}
+
+/* Return TRUE if the second (value) data type may be assigned to a variable of the first (variable) data type
+ * such as:
+ *     var_type     value_type
+ *    BOOL           BYTE#7     -> returns false
+ *    INT            INT#7      -> returns true
+ *    INT            7          -> returns true
+ *    REAL           7.89       -> returns true
+ *    REAL           7          -> returns true
+ *    INT            7.89       -> returns false
+ *    SAFEBOOL       BOOL#1     -> returns false   !!!
+ *   etc...
+ *
+ * NOTE: It is assumed that the var_type is the data type of an lvalue
+ */
+bool is_valid_assignment(symbol_c *var_type, symbol_c *value_type) {
+  if (var_type == NULL)   {/* STAGE3_ERROR(value_type, value_type, "Var_type   == NULL"); */ return false;}
+  if (value_type == NULL) {/* STAGE3_ERROR(var_type,   var_type,   "Value_type == NULL"); */ return false;}
+
+  symbol_c *common_type_symbol = common_type(var_type, value_type);
+  if (NULL == common_type_symbol)
+    return false;
+  return (typeid(*var_type) == typeid(*common_type_symbol));
+}
+
+
+/* Return TRUE if there is a common data type, otherwise return FALSE
+ * i.e., return TRUE if both data types may be used simultaneously in an expression
+ * such as:
+ *    BOOL#0     AND BYTE#7  -> returns false
+ *    0          AND BYTE#7  -> returns true
+ *    INT#10     AND INT#7   -> returns true
+ *    INT#10     AND 7       -> returns true
+ *    REAL#34.3  AND 7.89    -> returns true
+ *    REAL#34.3  AND 7       -> returns true
+ *    INT#10     AND 7.89    -> returns false
+ *    SAFEBOOL#0 AND BOOL#1  -> returns true   !!!
+ *   etc...
+ */
+bool is_compatible_type(symbol_c *first_type, symbol_c *second_type) {
+  if (first_type == NULL || second_type == NULL) {return false;}
+  return (NULL != common_type(first_type, second_type));
+}
+
+bool is_type_equal(symbol_c *first_type, symbol_c *second_type)
+{
+    if (first_type == NULL || second_type == NULL) {
+        return false;
+    }
+    if (is_ANY_ELEMENTARY_type(first_type)) {
+        if (typeid(*first_type) == typeid(*second_type))
+            return true;
+    } else   /* ANY_DERIVED */
+        return (first_type == second_type);
+
+    return false;
+}