etisserant@0: /*
etisserant@0:  * (c) 2003 Mario de Sousa
etisserant@0:  *
etisserant@0:  * Offered to the public under the terms of the GNU General Public License
etisserant@0:  * as published by the Free Software Foundation; either version 2 of the
etisserant@0:  * License, or (at your option) any later version.
etisserant@0:  *
etisserant@0:  * This program is distributed in the hope that it will be useful, but
etisserant@0:  * WITHOUT ANY WARRANTY; without even the implied warranty of
etisserant@0:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
etisserant@0:  * Public License for more details.
etisserant@0:  *
etisserant@0:  * This code is made available on the understanding that it will not be
etisserant@0:  * used in safety-critical situations without a full and competent review.
etisserant@0:  */
etisserant@0: 
etisserant@0: /*
etisserant@0:  * An IEC 61131-3 IL and ST compiler.
etisserant@0:  *
etisserant@0:  * Based on the
etisserant@0:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
etisserant@0:  *
etisserant@0:  */
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: /* Determine the data type of a variable.
etisserant@0:  * The variable may be a simple variable, a function block instance, a
etisserant@0:  * struture element within a data structured type (a struct or a fb), or
etisserant@0:  * an array element.
etisserant@0:  * A mixture of array element of a structure element of a structure element
etisserant@0:  * of a .... is also suported!
etisserant@0:  *
etisserant@0:  * A reference to the relevant base type __definition__ is returned.
etisserant@0:  * This means that if we find that the variable is of type MY_INT,
etisserant@0:  * which was previously declared to be
etisserant@0:  * TYPE MY_INT: INT := 9;
etisserant@0:  * this class wil return INT, and __not__ MY_INT !!
etisserant@0:  *
etisserant@0:  *
etisserant@0:  *  example:
etisserant@0:  *    window.points[1].coordinate.x
etisserant@0:  *    window.points[1].colour
etisserant@0:  *    etc... ARE ALLOWED!
etisserant@0:  *
etisserant@0:  * This class must be passed the scope within which the
etisserant@0:  * variable was declared, and the variable name...
etisserant@0:  */
etisserant@0: class search_varfb_instance_type_c: public search_base_type_c {
etisserant@0:   private:
etisserant@0:     search_var_instance_decl_c search_var_instance_decl;
etisserant@0:     decompose_var_instance_name_c *decompose_var_instance_name;
etisserant@0:     symbol_c *current_structelement_name;
etisserant@0: 
etisserant@0:   public:
etisserant@0:     search_varfb_instance_type_c(symbol_c *search_scope): search_var_instance_decl(search_scope) {
etisserant@0:       this->decompose_var_instance_name = NULL;
etisserant@0:       this->current_structelement_name = NULL;
etisserant@0:     }
etisserant@0: 
etisserant@0: 
etisserant@0:     symbol_c *get_type(symbol_c *variable_name) {
etisserant@0:       this->current_structelement_name = NULL;
etisserant@0:       this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
etisserant@0:       if (NULL == decompose_var_instance_name) ERROR;
etisserant@0: 
etisserant@0:       /* find the part of the variable name that will appear in the
etisserant@0:        * variable declaration, for e.g., in window.point.x, this would be
etisserant@0:        * window!
etisserant@0:        */
etisserant@0:       symbol_c *var_name_part = decompose_var_instance_name->next_part();
etisserant@0:       if (NULL == var_name_part) ERROR;
etisserant@0: 
etisserant@0:       /* Now we try to find the variable instance declaration, to determine its type... */
etisserant@0:       symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
etisserant@0:       if (NULL == var_decl) {
etisserant@0:         /* variable instance declaration not found! */
etisserant@0:  	return NULL;
etisserant@0:       }
etisserant@0: 
etisserant@0:       /* if it is a struct or function block, we must search the type
etisserant@0:        * of the struct or function block member.
etisserant@0:        * This is done by this class visiting the var_decl.
etisserant@0:        * This class, while visiting, will recursively call
etisserant@0:        * decompose_var_instance_name->get_next() when and if required...
etisserant@0:        */
etisserant@0:       symbol_c *res = (symbol_c *)var_decl->accept(*this);
etisserant@0:       if (NULL == res) ERROR;
etisserant@0: 
etisserant@0:       /* make sure that we have decomposed all strcuture elements of the variable name */
etisserant@0:       symbol_c *var_name = decompose_var_instance_name->next_part();
etisserant@0:       if (NULL != var_name) ERROR;
etisserant@0: 
etisserant@0:       return res;
etisserant@0:     }
etisserant@0: 
etisserant@0:   private:
etisserant@0:     /* a helper function... */
etisserant@0:     void *visit_list(list_c *list)	{
etisserant@0:       if (NULL == current_structelement_name) ERROR;
etisserant@0: 
etisserant@0:       for(int i = 0; i < list->n; i++) {
etisserant@0:         void *res = list->elements[i]->accept(*this);
etisserant@0:         if (res != NULL)
etisserant@0:           return res;
etisserant@0:       }
etisserant@0:       /* not found! */
etisserant@0:       return NULL;
etisserant@0:     }
etisserant@0: 
etisserant@0:     /* a helper function... */
etisserant@0:     void *base_type(symbol_c *symbol)	{
etisserant@0:         search_base_type_c search_base_type;
etisserant@0: 	return symbol->accept(search_base_type);
etisserant@0:     }
etisserant@0: 
etisserant@0: 
etisserant@0:   private:
etisserant@0:     /* We override the base class' visitor to identifier_c.
etisserant@0:      * This is so because the base class does not consider a function block
etisserant@0:      * to be a type, unlike this class that allows a variable instance
etisserant@0:      * of a function block type...
etisserant@0:      */
etisserant@0:     void *visit(identifier_c *type_name) {
etisserant@0:       /* look up the type declaration... */
etisserant@0:       symbol_c *fb_decl = function_block_type_symtable.find_value(type_name);
etisserant@0:       if (fb_decl != function_block_type_symtable.end_value())
etisserant@0:         /* Type declaration found!! */
etisserant@0: 	return fb_decl->accept(*this);
etisserant@0: 
etisserant@0:       /* No. It is not a function block, so we let
etisserant@0:        * the base class take care of it...
etisserant@0:        */
etisserant@0:       return search_base_type_c::visit(type_name);
etisserant@0:     }
etisserant@0: 
etisserant@0: /********************************/
etisserant@0: /* B 1.3.3 - Derived data types */
etisserant@0: /********************************/
etisserant@0: /*  structure_type_name ':' structure_specification */
etisserant@0:     void *visit(structure_type_declaration_c *symbol) {
etisserant@0:       return symbol->structure_specification->accept(*this);
etisserant@0:       /* NOTE: structure_specification will point to either a
etisserant@0:        *       initialized_structure_c
etisserant@0:        *       OR A
etisserant@0:        *       structure_element_declaration_list_c
etisserant@0:        */
etisserant@0:     }
etisserant@0: 
etisserant@0: /* structure_type_name ASSIGN structure_initialization */
etisserant@0: /* structure_initialization may be NULL ! */
etisserant@0: // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)
etisserant@0:     void *visit(initialized_structure_c *symbol)	{
etisserant@0:       /* make sure that we have decomposed all strcuture elements of the variable name */
etisserant@0:       symbol_c *var_name = decompose_var_instance_name->next_part();
etisserant@0:       if (NULL == var_name) {
etisserant@0:         /* this is it... !
etisserant@0: 	  * No need to look any further...
etisserant@0: 	 */
etisserant@0: 	/* NOTE: we could simply do a
etisserant@0: 	 *   return (void *)symbol;
etisserant@0: 	 *       nevertheless, note that this search_varfb_instance_type_c
etisserant@0: 	 *       class inherits from the search_base_type_c class,
etisserant@0: 	 *       which means that it will usually return the base type,
etisserant@0: 	 *       and not the derived type (*). If we are to be consistent,
etisserant@0: 	 *       we should guarantee that we always return the base type.
etisserant@0: 	 *       To do this we could use
etisserant@0: 	 *   return (void *)symbol->accept(*this);
etisserant@0: 	 *       since this class inherits from the search_base_type_c.
etisserant@0: 	 *       However, in this case we don't want it to follow
etisserant@0: 	 *       the structs as this search_varfb_instance_type_c does.
etisserant@0: 	 *       We therefore have to create a new search_base_type_c
etisserant@0: 	 *       instance to search through this type without going
etisserant@0: 	 *       through the structs...
etisserant@0: 	 */
etisserant@0:         return base_type(symbol->structure_type_name);
etisserant@0:       }
etisserant@0: 
etisserant@0:       /* now search the structure declaration */
etisserant@0:       current_structelement_name = var_name;
etisserant@0:       /* recursively find out the data type of var_name... */
etisserant@0:       return symbol->structure_type_name->accept(*this);
etisserant@0:     }
etisserant@0: 
etisserant@0: /* helper symbol for structure_declaration */
etisserant@0: /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */
etisserant@0: /* structure_element_declaration_list structure_element_declaration ';' */
etisserant@0:     void *visit(structure_element_declaration_list_c *symbol)	{return visit_list(symbol);}
etisserant@0: 
etisserant@0: /*  structure_element_name ':' spec_init */
etisserant@0:     void *visit(structure_element_declaration_c *symbol) {
etisserant@0:       if (NULL == current_structelement_name) ERROR;
etisserant@0: 
etisserant@0:       if (compare_identifiers(symbol->structure_element_name, current_structelement_name) == 0)
etisserant@0:         return symbol->spec_init->accept(*this);
etisserant@0: 
etisserant@0:       return NULL;
etisserant@0:     }
etisserant@0: 
etisserant@0: /* helper symbol for structure_initialization */
etisserant@0: /* structure_initialization: '(' structure_element_initialization_list ')' */
etisserant@0: /* structure_element_initialization_list ',' structure_element_initialization */
etisserant@0:     void *visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */
etisserant@0: /*  structure_element_name ASSIGN value */
etisserant@0:     void *visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: /**************************************/
etisserant@0: /* B.1.5 - Program organization units */
etisserant@0: /**************************************/
etisserant@0: /*****************************/
etisserant@0: /* B 1.5.2 - Function Blocks */
etisserant@0: /*****************************/
etisserant@0: /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
etisserant@0: // SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)
etisserant@0:     void *visit(function_block_declaration_c *symbol) {
etisserant@0:       /* make sure that we have decomposed all strcuture elements of the variable name */
etisserant@0: 
etisserant@0:       symbol_c *var_name = decompose_var_instance_name->next_part();
etisserant@0:       if (NULL == var_name) {
etisserant@0:         /* this is it... !
etisserant@0: 	 * No need to look any further...
etisserant@0: 	 * Note also that, unlike for the struct types, a function block may
etisserant@0: 	 * not be defined based on another (i.e. no inheritance is allowed),
etisserant@0: 	 * so this function block is already the most base type.
etisserant@0: 	 * We simply return it.
etisserant@0: 	 */
etisserant@0: 	return (void *)symbol;
etisserant@0:       }
etisserant@0: 
etisserant@0:       /* now search the function block declaration for the variable... */
etisserant@0:       search_var_instance_decl_c search_decl(symbol);
etisserant@0:       symbol_c *var_decl = search_decl.get_decl(var_name);
etisserant@0:       if (NULL == var_decl) {
etisserant@0:         /* variable instance declaration not found! */
etisserant@0:  	return NULL;
etisserant@0:       }
etisserant@0: 
etisserant@0:       /* We have found the declaration.
etisserant@0:        * Should we look any further?
etisserant@0:        */
etisserant@0:       var_name = decompose_var_instance_name->next_part();
etisserant@0:       if (NULL == var_name) {
etisserant@0:         /* this is it... ! */
etisserant@0: 	return base_type(var_decl);
etisserant@0:       }
etisserant@0: 
etisserant@0:       current_structelement_name = var_name;
etisserant@0:       /* recursively find out the data type of var_name... */
etisserant@0:       return symbol->var_declarations->accept(*this);
etisserant@0:     }
etisserant@0: 
etisserant@0: };
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: