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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 a variable.
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* The variable may be a simple variable, a function block instance, a
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* struture element within a data structured type (a struct or a fb), or
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* an array element.
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* A mixture of array element of a structure element of a structure element
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* of a .... is also suported!
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*
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* A reference to the relevant base type __definition__ is returned.
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* This means that if we find that the variable is of type MY_INT,
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* which was previously declared to be
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* TYPE MY_INT: INT := 9;
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* this class wil return INT, and __not__ MY_INT !!
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*
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*
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* example:
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* window.points[1].coordinate.x
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* window.points[1].colour
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* etc... ARE ALLOWED!
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*
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* This class must be passed the scope within which the
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* variable was declared, and the variable name...
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*/
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class search_varfb_instance_type_c: public search_base_type_c {
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private:
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search_var_instance_decl_c search_var_instance_decl;
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decompose_var_instance_name_c *decompose_var_instance_name;
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symbol_c *current_structelement_name;
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bool search_base_type;
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public:
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search_varfb_instance_type_c(symbol_c *search_scope): search_var_instance_decl(search_scope) {
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this->decompose_var_instance_name = NULL;
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this->current_structelement_name = NULL;
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this->search_base_type = false;
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}
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symbol_c *get_type(symbol_c *variable_name, bool base_type = true) {
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this->current_structelement_name = NULL;
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this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
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this->search_base_type = base_type;
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if (NULL == decompose_var_instance_name) ERROR;
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/* find the part of the variable name that will appear in the
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* variable declaration, for e.g., in window.point.x, this would be
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* window!
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*/
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symbol_c *var_name_part = decompose_var_instance_name->next_part();
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if (NULL == var_name_part) ERROR;
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/* Now we try to find the variable instance declaration, to determine its type... */
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symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
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if (NULL == var_decl) {
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/* variable instance declaration not found! */
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return NULL;
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}
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/* if it is a struct or function block, we must search the type
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* of the struct or function block member.
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* This is done by this class visiting the var_decl.
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* This class, while visiting, will recursively call
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* decompose_var_instance_name->get_next() when and if required...
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*/
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symbol_c *res = (symbol_c *)var_decl->accept(*this);
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if (NULL == res) ERROR;
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/* make sure that we have decomposed all strcuture elements of the variable name */
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symbol_c *var_name = decompose_var_instance_name->next_part();
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if (NULL != var_name) ERROR;
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return res;
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}
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unsigned int get_vartype(symbol_c *variable_name) {
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this->current_structelement_name = NULL;
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this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
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if (NULL == decompose_var_instance_name) ERROR;
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/* find the part of the variable name that will appear in the
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* variable declaration, for e.g., in window.point.x, this would be
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* window!
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*/
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symbol_c *var_name_part = decompose_var_instance_name->next_part();
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if (NULL == var_name_part) ERROR;
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/* Now we try to find the variable instance declaration, to determine its type... */
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symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
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if (NULL == var_decl) {
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/* variable instance declaration not found! */
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return 0;
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}
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/* if it is a struct or function block, we must search the type
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* of the struct or function block member.
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* This is done by this class visiting the var_decl.
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* This class, while visiting, will recursively call
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* decompose_var_instance_name->get_next() when and if required...
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*/
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unsigned int res = search_var_instance_decl.get_vartype();
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/* make sure that we have decomposed all strcuture elements of the variable name */
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symbol_c *var_name = decompose_var_instance_name->next_part();
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if (NULL != var_name) ERROR;
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return res;
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}
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private:
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/* a helper function... */
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void *visit_list(list_c *list) {
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if (NULL == current_structelement_name) ERROR;
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for(int i = 0; i < list->n; i++) {
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void *res = list->elements[i]->accept(*this);
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if (res != NULL)
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return res;
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}
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/* not found! */
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return NULL;
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}
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/* a helper function... */
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void *base_type(symbol_c *symbol) {
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search_base_type_c search_base_type;
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return symbol->accept(search_base_type);
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}
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private:
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/* We override the base class' visitor to identifier_c.
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* This is so because the base class does not consider a function block
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* to be a type, unlike this class that allows a variable instance
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* of a function block type...
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*/
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void *visit(identifier_c *type_name) {
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/* look up the type declaration... */
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symbol_c *fb_decl = function_block_type_symtable.find_value(type_name);
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if (fb_decl != function_block_type_symtable.end_value())
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/* Type declaration found!! */
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return fb_decl->accept(*this);
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/* No. It is not a function block, so we let
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* the base class take care of it...
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*/
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if (this->search_base_type)
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return search_base_type_c::visit(type_name);
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else
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return type_name;
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}
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/********************************/
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/* B 1.3.3 - Derived data types */
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/********************************/
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/* identifier ':' array_spec_init */
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void *visit(array_type_declaration_c *symbol) {
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return symbol->array_spec_init->accept(*this);
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}
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/* array_specification [ASSIGN array_initialization} */
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/* array_initialization may be NULL ! */
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void *visit(array_spec_init_c *symbol) {
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return symbol->array_specification->accept(*this);
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}
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/* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */
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void *visit(array_specification_c *symbol) {
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return symbol->non_generic_type_name->accept(*this);
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}
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/* structure_type_name ':' structure_specification */
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void *visit(structure_type_declaration_c *symbol) {
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return symbol->structure_specification->accept(*this);
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/* NOTE: structure_specification will point to either a
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* initialized_structure_c
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* OR A
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* structure_element_declaration_list_c
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*/
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}
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/* structure_type_name ASSIGN structure_initialization */
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/* structure_initialization may be NULL ! */
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// SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)
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void *visit(initialized_structure_c *symbol) {
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/* make sure that we have decomposed all strcuture elements of the variable name */
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symbol_c *var_name = decompose_var_instance_name->next_part();
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if (NULL == var_name) {
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/* this is it... !
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* No need to look any further...
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*/
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/* NOTE: we could simply do a
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* return (void *)symbol;
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* nevertheless, note that this search_varfb_instance_type_c
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* class inherits from the search_base_type_c class,
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* which means that it will usually return the base type,
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* and not the derived type (*). If we are to be consistent,
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* we should guarantee that we always return the base type.
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* To do this we could use
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* return (void *)symbol->accept(*this);
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* since this class inherits from the search_base_type_c.
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* However, in this case we don't want it to follow
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* the structs as this search_varfb_instance_type_c does.
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* We therefore have to create a new search_base_type_c
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* instance to search through this type without going
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* through the structs...
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*/
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return base_type(symbol->structure_type_name);
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}
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/* now search the structure declaration */
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current_structelement_name = var_name;
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/* recursively find out the data type of var_name... */
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return symbol->structure_type_name->accept(*this);
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}
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/* helper symbol for structure_declaration */
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/* structure_declaration: STRUCT structure_element_declaration_list END_STRUCT */
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/* structure_element_declaration_list structure_element_declaration ';' */
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void *visit(structure_element_declaration_list_c *symbol) {return visit_list(symbol);}
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/* structure_element_name ':' spec_init */
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void *visit(structure_element_declaration_c *symbol) {
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if (NULL == current_structelement_name) ERROR;
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if (compare_identifiers(symbol->structure_element_name, current_structelement_name) == 0)
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return symbol->spec_init->accept(*this);
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return NULL;
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}
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/* helper symbol for structure_initialization */
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/* structure_initialization: '(' structure_element_initialization_list ')' */
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/* structure_element_initialization_list ',' structure_element_initialization */
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void *visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */
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/* structure_element_name ASSIGN value */
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void *visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */
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/**************************************/
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/* B.1.5 - Program organization units */
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/**************************************/
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/*****************************/
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/* B 1.5.2 - Function Blocks */
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/*****************************/
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/* FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
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// SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)
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void *visit(function_block_declaration_c *symbol) {
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/* make sure that we have decomposed all strcuture elements of the variable name */
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symbol_c *var_name = decompose_var_instance_name->next_part();
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if (NULL == var_name) {
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/* this is it... !
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* No need to look any further...
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* Note also that, unlike for the struct types, a function block may
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* not be defined based on another (i.e. no inheritance is allowed),
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* so this function block is already the most base type.
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* We simply return it.
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*/
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return (void *)symbol;
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}
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/* now search the function block declaration for the variable... */
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search_var_instance_decl_c search_decl(symbol);
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symbol_c *var_decl = search_decl.get_decl(var_name);
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if (NULL == var_decl) {
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/* variable instance declaration not found! */
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return NULL;
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}
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/* We have found the declaration.
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* Should we look any further?
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*/
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var_name = decompose_var_instance_name->next_part();
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if (NULL == var_name) {
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/* this is it... ! */
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return base_type(var_decl);
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}
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current_structelement_name = var_name;
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/* recursively find out the data type of var_name... */
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return symbol->var_declarations->accept(*this);
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}
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};
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