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/*

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 * (c) 2003 Mario de Sousa

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 *

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 * Offered to the public under the terms of the GNU General Public License

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 * as published by the Free Software Foundation; either version 2 of the

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 * License, or (at your option) any later version.

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 *

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 * This program is distributed in the hope that it will be useful, but

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 * WITHOUT ANY WARRANTY; without even the implied warranty of

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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

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 * Public License for more details.

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 *

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 * This code is made available on the understanding that it will not be

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 * used in safety-critical situations without a full and competent review.

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 */

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/*

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 * An IEC 61131-3 IL and ST compiler.

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 *

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 * Based on the

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 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

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 *

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 */

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/* Determine the data type of an ST expression.

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 * A reference to the relevant type definition is returned.

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 *

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 * For example:

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 *       2 + 3       -> returns reference to a int_type_name_c object.

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 *       22.2 - 5    -> returns reference to a real_type_name_c object.

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 *       etc...

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 */

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class search_expression_type_c: public search_constant_type_c {

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  private:

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    search_varfb_instance_type_c *search_varfb_instance_type;

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    search_base_type_c search_base_type;

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  public:

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    search_expression_type_c(symbol_c *search_scope) {

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      search_varfb_instance_type = new search_varfb_instance_type_c(search_scope);

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    }

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    virtual ~search_expression_type_c(void) {

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      delete search_varfb_instance_type;

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    }

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    /* A helper function... */

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    bool is_bool_type(symbol_c *type_symbol) {

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      return (typeid(*type_symbol) == typeid(bool_type_name_c));

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    }

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    /* A helper function... */

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    bool is_time_compatible(symbol_c *type_symbol) {

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      if (typeid(*type_symbol) == typeid(time_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(date_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(tod_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(dt_type_name_c)) {return true;}

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      return false;

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    }

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    /* A helper function... */

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    bool is_numeric_compatible(symbol_c *type_symbol) {

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      if (typeid(*type_symbol) == typeid(sint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(int_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(dint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(lint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(usint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(uint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(udint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(ulint_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(real_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(lreal_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(bool_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(byte_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(word_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(dword_type_name_c)) {return true;}

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      if (typeid(*type_symbol) == typeid(lword_type_name_c)) {return true;}

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      return false;

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    }

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  private:

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  static bool_type_name_c bool_type_name;

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  /* A helper function... */

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  void *compute_boolean_expression(symbol_c *left_type, symbol_c *right_type) {

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    if (typeid(*left_type) == typeid(bool_type_name_c) and typeid(*right_type) == typeid(bool_type_name_c)) {return (void *)left_type;}

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    if (is_numeric_compatible(left_type) && is_numeric_compatible(right_type)) {return (void *)left_type;}

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    ERROR;

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    return NULL;

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  }

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  /* A helper function... */

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  void *compute_numeric_expression(symbol_c *left_type, symbol_c *right_type) {

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    if (is_numeric_compatible(left_type) && is_numeric_compatible(right_type)) {return (void *)left_type;}

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    ERROR;

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    return NULL;

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  }

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  /* a helper function... */

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  symbol_c *base_type(symbol_c *symbol) {

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    return (symbol_c *)symbol->accept(search_base_type);

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  }

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/*********************/

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/* B 1.4 - Variables */

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/*********************/

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  void *visit(symbolic_variable_c *symbol) {

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    symbol_c *res;

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    /* Nope, now we assume it is a variable, and determine its type... */

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    res = search_varfb_instance_type->get_type(symbol);

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    if (NULL != res) return res;

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    return NULL;

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  }

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/***************************************/

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/* B.3 - Language ST (Structured Text) */

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/***************************************/

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/***********************/

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/* B 3.1 - Expressions */

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/***********************/

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  void *visit(or_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    return compute_boolean_expression(left_type, right_type);

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  }

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  void *visit(xor_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    return compute_boolean_expression(left_type, right_type);

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  }

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  void *visit(and_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    return compute_boolean_expression(left_type, right_type); 

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  }

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  void *visit(equ_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(notequ_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(lt_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(gt_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(le_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(ge_expression_c *symbol) {return (void *)&bool_type_name;}

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  void *visit(add_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}

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    return compute_numeric_expression(left_type, right_type);

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  }

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  void *visit(sub_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}

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    return compute_numeric_expression(left_type, right_type);

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  }

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  void *visit(mul_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    if (is_time_compatible(left_type) && is_time_compatible(right_type)) {return left_type;}

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    return compute_numeric_expression(left_type, right_type);

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  }

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  void *visit(div_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    return compute_numeric_expression(left_type, right_type);

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  }

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  void *visit(mod_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    return compute_numeric_expression(left_type, right_type);

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  }

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  void *visit(power_expression_c *symbol) {

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    symbol_c *left_type = base_type((symbol_c *)symbol->l_exp->accept(*this));

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    symbol_c *right_type = base_type((symbol_c *)symbol->r_exp->accept(*this));

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(real_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(sint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(int_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(dint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(lint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(usint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(uint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(udint_type_name_c)) {return (void *)left_type;}

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    if (typeid(*left_type) == typeid(lreal_type_name_c) and typeid(*right_type) == typeid(ulint_type_name_c)) {return (void *)left_type;}

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    ERROR;

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    return NULL;

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  }

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  void *visit(neg_expression_c *symbol) {

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    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));

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    if (typeid(*exp_type) == typeid(sint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(int_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(dint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(lint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(usint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(uint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(udint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(ulint_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(real_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(lreal_type_name_c)) {return (void *)exp_type;}

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    if (typeid(*exp_type) == typeid(time_type_name_c)) {return (void *)exp_type;}

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    ERROR;

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    return NULL;

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  }

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  void *visit(not_expression_c *symbol) {

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    symbol_c *exp_type = base_type((symbol_c *)symbol->exp->accept(*this));

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    if (typeid(*exp_type) == typeid(bool_type_name_c)) {return (void *)exp_type;}

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    ERROR;

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    return NULL;

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  }

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  void *visit(function_invocation_c *symbol) {

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	  function_declaration_c *f_decl = function_symtable.find_value(symbol->function_name);

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	  if (f_decl == function_symtable.end_value())

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	    /* should never occur. The function being called MUST be in the symtable... */

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	    ERROR;

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    return base_type(f_decl->type_name);

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  }

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};

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bool_type_name_c     search_expression_type_c::bool_type_name;

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