diff -r 0b472e25eb16 -r e8b99f896416 stage4/generate_cc/search_expression_type.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/stage4/generate_cc/search_expression_type.cc	Tue Feb 20 18:17:21 2007 +0100
@@ -0,0 +1,244 @@
+/*
+ * (c) 2003 Mario de Sousa
+ *
+ * Offered to the public under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2 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.
+ *
+ * This code is made available on the understanding that it will not be
+ * used in safety-critical situations without a full and competent review.
+ */
+
+/*
+ * An IEC 61131-3 IL and ST compiler.
+ *
+ * Based on the
+ * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
+ *
+ */
+
+
+/* Determine the data type of an ST expression.
+ * A reference to the relevant type definition is returned.
+ *
+ * For example:
+ *       2 + 3       -> returns reference to a int_type_name_c object.
+ *       22.2 - 5    -> returns reference to a real_type_name_c object.
+ *       etc...
+ */
+class search_expression_type_c: public search_constant_type_c {
+  private:
+    search_varfb_instance_type_c *search_varfb_instance_type;
+    search_base_type_c search_base_type;
+
+  public:
+    search_expression_type_c(symbol_c *search_scope) {
+      search_varfb_instance_type = new search_varfb_instance_type_c(search_scope);
+    }
+
+    virtual ~search_expression_type_c(void) {
+      delete search_varfb_instance_type;
+    }
+
+    /* A helper function... */
+    bool is_bool_type(symbol_c *type_symbol) {
+      return (typeid(*type_symbol) == typeid(bool_type_name_c));
+    }
+
+    /* A helper function... */
+    bool is_time_compatible(symbol_c *type_symbol) {
+      if (typeid(*type_symbol) == typeid(time_type_name_c)) {return true;}
+      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_numeric_compatible(symbol_c *type_symbol) {
+      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;}
+      if (typeid(*type_symbol) == typeid(real_type_name_c)) {return true;}
+      if (typeid(*type_symbol) == typeid(lreal_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;
+    }
+    
+  private:
+
+  static bool_type_name_c bool_type_name;
+
+  /* A helper function... */
+  void *compute_boolean_expression(symbol_c *left_type, symbol_c *right_type) {
+    if (typeid(*left_type) == typeid(bool_type_name_c) and typeid(*right_type) == typeid(bool_type_name_c)) {return (void *)left_type;}
+    if (is_numeric_compatible(left_type) && is_numeric_compatible(right_type)) {return (void *)left_type;}
+    ERROR;
+    return NULL;
+  }
+
+  /* A helper function... */
+  void *compute_numeric_expression(symbol_c *left_type, symbol_c *right_type) {
+    if (is_numeric_compatible(left_type) && is_numeric_compatible(right_type)) {return (void *)left_type;}
+    ERROR;
+    return NULL;
+  }
+
+  /* a helper function... */
+  symbol_c *base_type(symbol_c *symbol) {
+    return (symbol_c *)symbol->accept(search_base_type);
+  }
+
+/*********************/
+/* B 1.4 - Variables */
+/*********************/
+
+  void *visit(symbolic_variable_c *symbol) {
+    symbol_c *res;
+    
+    /* Nope, now we assume it is a variable, and determine its type... */
+    res = search_varfb_instance_type->get_type(symbol);
+    if (NULL != res) return res;
+    
+    return NULL;
+  }
+
+
+/***************************************/
+/* B.3 - Language ST (Structured Text) */
+/***************************************/
+/***********************/
+/* B 3.1 - Expressions */
+/***********************/
+  void *visit(or_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    return compute_boolean_expression(left_type, right_type);
+  }
+
+  void *visit(xor_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    return compute_boolean_expression(left_type, right_type);
+  }
+
+  void *visit(and_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    return compute_boolean_expression(left_type, right_type); 
+  }
+
+  void *visit(equ_expression_c *symbol) {return (void *)&bool_type_name;}
+  void *visit(notequ_expression_c *symbol) {return (void *)&bool_type_name;}
+  void *visit(lt_expression_c *symbol) {return (void *)&bool_type_name;}
+  void *visit(gt_expression_c *symbol) {return (void *)&bool_type_name;}
+  void *visit(le_expression_c *symbol) {return (void *)&bool_type_name;}
+  void *visit(ge_expression_c *symbol) {return (void *)&bool_type_name;}
+
+  void *visit(add_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}
+    return compute_numeric_expression(left_type, right_type);
+  }
+
+  void *visit(sub_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}
+    return compute_numeric_expression(left_type, right_type);
+  }
+  
+  void *visit(mul_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}
+    return compute_numeric_expression(left_type, right_type);
+  }
+  
+  void *visit(div_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    return compute_numeric_expression(left_type, right_type);
+  }
+
+  void *visit(mod_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    return compute_numeric_expression(left_type, right_type);
+  }
+
+  void *visit(power_expression_c *symbol) {
+    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));
+    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}
+    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}
+    ERROR;
+    return NULL;
+  }
+  
+  void *visit(neg_expression_c *symbol) {
+    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));
+    if (typeid(*exp_type) == typeid(sint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(int_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(dint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(lint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(usint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(uint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(udint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(ulint_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(real_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(lreal_type_name_c)) {return (void *)exp_type;}
+    if (typeid(*exp_type) == typeid(time_type_name_c)) {return (void *)exp_type;}
+    ERROR;
+    return NULL;
+  }
+  
+  void *visit(not_expression_c *symbol) {
+    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));
+    if (typeid(*exp_type) == typeid(bool_type_name_c)) {return (void *)exp_type;}
+    ERROR;
+    return NULL;
+  }
+  
+  void *visit(function_invocation_c *symbol) {
+	  function_declaration_c *f_decl = function_symtable.find_value(symbol->function_name);
+	
+	  if (f_decl == function_symtable.end_value())
+	    /* should never occur. The function being called MUST be in the symtable... */
+	    ERROR;
+
+    return base_type(f_decl->type_name);
+  }
+
+};
+
+bool_type_name_c     search_expression_type_c::bool_type_name;
+