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 default initial value of a type declaration.
etisserant@0:  *
etisserant@0:  * This is part of the 4th stage that generates
etisserant@0:  * a c++ source program equivalent to the IL and ST
etisserant@0:  * code.
etisserant@0:  */
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: //#include <stdio.h>  /* required for NULL */
etisserant@0: //#include <string>
etisserant@0: //#include <iostream>
etisserant@0: 
etisserant@0: //#include "../../util/symtable.hh"
etisserant@0: 
etisserant@0: //#include "generate_cc.hh"
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: /* Given a type definition declration, determine its default
etisserant@0:  * initial value. Note that types based on other types
etisserant@0:  * may have to iterate through each type it is based on
etisserant@0:  * to determine the initial value.
etisserant@0:  * E.g.
etisserant@0:  *  TYPE
etisserant@0:  *    A_t : INT := 10;
etisserant@0:  *    B_t : A_t := 20;
etisserant@0:  *    C_t : B_t;
etisserant@0:  *    D_t : C_t := 40;
etisserant@0:  *  END_TYPE
etisserant@0:  * Where the default initial value for C_t is 20!
etisserant@0:  */
etisserant@0: /* NOTE: The main program only needs one instance of
etisserant@0:  *       this class of object. This class
etisserant@0:  *       is therefore a singleton.
etisserant@0:  */
etisserant@0: class type_initial_value_c : public null_visitor_c {
etisserant@0:   private:
etisserant@0:     static type_initial_value_c *_instance;
etisserant@0:     /* constants for the default values of elementary data types... */
etisserant@0:     static real_c		*real_0;
etisserant@0:     static integer_c		*integer_0, *integer_1;
etisserant@0:     static boolean_literal_c	*bool_0;
etisserant@0:     static date_literal_c	*date_literal_0;
etisserant@0:     static daytime_c		*daytime_literal_0;
etisserant@0:     static duration_c		*time_0;
etisserant@0:     static date_c		*date_0;
etisserant@0:     static time_of_day_c	*tod_0;
etisserant@0:     static date_and_time_c	*dt_0;
etisserant@0:     static single_byte_character_string_c *string_0;
etisserant@0:     static double_byte_character_string_c *wstring_0;
etisserant@0: 
etisserant@0:   public:
etisserant@0:     static type_initial_value_c *instance(void) {
etisserant@0:       if (_instance != NULL)
etisserant@0:         return _instance;
etisserant@0: 
etisserant@0:       _instance = new type_initial_value_c;
etisserant@0: 
etisserant@0:       real_0 = new real_c("0");
etisserant@0:       integer_0 = new integer_c("0");
etisserant@0:       integer_1 = new integer_c("1");
etisserant@0:       bool_0 = new boolean_literal_c(new bool_type_name_c(),new boolean_false_c());
etisserant@0:       /* FIXME: Our current implementation only allows dates from 1970 onwards,
etisserant@0:        * but the standard defines the date 0001-01-01 as the default value
etisserant@0:        * for the DATE data type. Untill we fix our implementation, we use 1970-01-01
etisserant@0:        * as our default value!!
etisserant@0:        */
etisserant@0: //      date_literal_0 =  new date_literal_c(integer_1, integer_1, integer_1);
etisserant@0:       date_literal_0 =  new date_literal_c(new integer_c("1970"), integer_1, integer_1);
etisserant@0:       daytime_literal_0 = new daytime_c(integer_0, integer_0, real_0);
etisserant@0:       time_0 = new duration_c(NULL, new seconds_c(integer_0, NULL));  // T#0S
etisserant@0:       date_0 = new date_c(date_literal_0);  //  D#0001-01-01
etisserant@0:       tod_0 = new time_of_day_c(daytime_literal_0);  //  TOD#00:00:00
etisserant@0:       dt_0 = new date_and_time_c(date_literal_0, daytime_literal_0);  //  DT#0001-01-01-00:00:00
etisserant@0:       string_0  = new single_byte_character_string_c("''");
etisserant@0:       wstring_0 = new double_byte_character_string_c("\"\"");
etisserant@0: 
etisserant@0:       return _instance;
etisserant@0:     }
etisserant@0: 
etisserant@0:   protected:
etisserant@0:     type_initial_value_c(void) {}
etisserant@0: 
etisserant@0:   public:
etisserant@0:     symbol_c *get(identifier_c *type_name) {
etisserant@0:       TRACE("type_initial_value_c::get(): called ");
etisserant@0:       return (symbol_c *)type_name->accept(*this);
etisserant@0:     }
etisserant@0: 
etisserant@0: 
etisserant@0:   private:
etisserant@0:     void *handle_type_spec(symbol_c *base_type_name, symbol_c *type_spec_init) {
etisserant@0:       if (type_spec_init != NULL)
etisserant@0:          return type_spec_init;
etisserant@0:        /* no initial value specified, so we return
etisserant@0:        * the initial value of the type this type is based on...
etisserant@0:         */
etisserant@0:       return base_type_name->accept(*this);
etisserant@0:     }
etisserant@0: 
etisserant@0:   public:
etisserant@0:     void *visit(identifier_c *type_name) {
etisserant@0:       /* look up the type declaration... */
etisserant@0:       symbol_c *type_decl = type_symtable.find_value(type_name);
etisserant@0:       if (type_decl == type_symtable.end_value())
etisserant@0:         /* Type declaration not found!! */
etisserant@0: 	/* NOTE: Variables declared out of function block 'data types',
etisserant@0: 	 *    for eg:  VAR  timer: TON; END_VAR
etisserant@0: 	 * do not have a default value, so (TON) will never be found in the
etisserant@0: 	 * type symbol table. This means we cannot simply consider this
etisserant@0: 	 * an error and abort, but must rather return a NULL.
etisserant@0: 	 */
etisserant@0: 	return NULL;
etisserant@0: 
etisserant@0:       return type_decl->accept(*this);
etisserant@0:     }
etisserant@0: 
etisserant@0: /***********************************/
etisserant@0: /* B 1.3.1 - Elementary Data Types */
etisserant@0: /***********************************/
etisserant@0:     void *visit(time_type_name_c *symbol)	{return (void *)time_0;}
etisserant@0:     void *visit(bool_type_name_c *symbol)	{return (void *)bool_0;}
etisserant@0:     void *visit(sint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(int_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(dint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(lint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(usint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(uint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(udint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(ulint_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(real_type_name_c *symbol)	{return (void *)real_0;}
etisserant@0:     void *visit(lreal_type_name_c *symbol)	{return (void *)real_0;}
etisserant@0:     void *visit(date_type_name_c *symbol)	{return (void *)date_0;}
etisserant@0:     void *visit(tod_type_name_c *symbol)	{return (void *)tod_0;}
etisserant@0:     void *visit(dt_type_name_c *symbol)		{return (void *)dt_0;}
etisserant@0:     void *visit(byte_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(word_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(dword_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(lword_type_name_c *symbol)	{return (void *)integer_0;}
etisserant@0:     void *visit(string_type_name_c *symbol)	{return (void *)string_0;}
etisserant@0:     void *visit(wstring_type_name_c *symbol)	{return (void *)wstring_0;}
etisserant@0: 
etisserant@0: /********************************/
etisserant@0: /* B 1.3.3 - Derived data types */
etisserant@0: /********************************/
etisserant@0: /*  simple_type_name ':' simple_spec_init */
etisserant@0:     void *visit(simple_type_declaration_c *symbol) {
etisserant@0:       return symbol->simple_spec_init->accept(*this);
etisserant@0:     }
etisserant@0: /* simple_specification ASSIGN constant */
etisserant@0:     void *visit(simple_spec_init_c *symbol) {
etisserant@0:       return handle_type_spec(symbol->simple_specification, symbol->constant);
etisserant@0:     }
etisserant@0: /*  subrange_type_name ':' subrange_spec_init */
etisserant@0:     void *visit(subrange_type_declaration_c *symbol) {
etisserant@0:       return symbol->subrange_spec_init->accept(*this);
etisserant@0:     }
etisserant@0: /* subrange_specification ASSIGN signed_integer */
etisserant@0:     void *visit(subrange_spec_init_c *symbol) {
etisserant@0:       return handle_type_spec(symbol->subrange_specification, symbol->signed_integer);
etisserant@0:     }
etisserant@0: /*  integer_type_name '(' subrange')' */
etisserant@0:     void *visit(subrange_specification_c *symbol) {
etisserant@0:      /* if no initial value explicitly given, then use the lowest value of the subrange */
etisserant@0:       return symbol->subrange->accept(*this);
etisserant@0:     }
etisserant@0: /*  signed_integer DOTDOT signed_integer */
etisserant@0:     void *visit(subrange_c *symbol)	{return symbol->lower_limit;}
etisserant@0: /*  enumerated_type_name ':' enumerated_spec_init */
etisserant@0:     void *visit(enumerated_type_declaration_c *symbol) {
etisserant@0:       return symbol->enumerated_spec_init->accept(*this);
etisserant@0:     }
etisserant@0: /* enumerated_specification ASSIGN enumerated_value */
etisserant@0:     void *visit(enumerated_spec_init_c *symbol) {
etisserant@0:       return handle_type_spec(symbol->enumerated_specification, symbol->enumerated_value);
etisserant@0:     }
etisserant@0: /* helper symbol for enumerated_specification->enumerated_spec_init */
etisserant@0: /* enumerated_value_list ',' enumerated_value */
etisserant@0:     void *visit(enumerated_value_list_c *symbol) {
etisserant@0:      /* if no initial value explicitly given, then use the lowest value of the subrange */
etisserant@0:       return (void *)symbol->elements[0];
etisserant@0:     }
etisserant@0: /* enumerated_type_name '#' identifier */
etisserant@0: // SYM_REF2(enumerated_value_c, type, value)
etisserant@0:     void *visit(enumerated_value_c *symbol)	{ERROR; return NULL;}
etisserant@0: /*  identifier ':' array_spec_init */
etisserant@0:     void *visit(array_type_declaration_c *symbol) {
etisserant@0:       return symbol->array_spec_init->accept(*this);
etisserant@0:     }
etisserant@0: /* array_specification [ASSIGN array_initialization} */
etisserant@0: /* array_initialization may be NULL ! */
etisserant@0:     void *visit(array_spec_init_c *symbol) {
etisserant@0:       return handle_type_spec(symbol->array_specification, symbol->array_initialization);
etisserant@0:     }
etisserant@0: /* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */
etisserant@0:     void *visit(array_specification_c *symbol)	{
etisserant@0:       symbol_c *init_value = (symbol_c *)symbol->non_generic_type_name->accept(*this);
etisserant@0: 
etisserant@0:       /* Now build a array_initial_elements_list_c list, and populate it
etisserant@0:        * with 1 element of the array_initial_elements_c class
etisserant@0:        */
etisserant@0:       /* The array_initial_elements_c will contain a reference to the init_value,
etisserant@0:        * and another constant representing the number of elements in the array.
etisserant@0:        * In essence, we are building the equivilant of the following ST/IL code:
etisserant@0:        *    New_array_t : ARRAY [1..30, 51..60] of INT := [40(XXX)];
etisserant@0:        * from the user given code
etisserant@0:        *    New_array_t : ARRAY [1..30, 51..60] of INT;
etisserant@0:        * and replacing XXX with the default initial value of INT.
etisserant@0:        */
etisserant@0:       /* now we need to determine the number of elements in the array... */
etisserant@0:       /* Easier said than done, as the array may have a list of subranges, as in the
etisserant@0:        * example given above!!
etisserant@0:        */
etisserant@0:       /* TODO !!!!!*/
etisserant@0:       /* For now, just assume an array with 1 element.
etisserant@0:        * I (Mario) want to finish off this part of the code before getting boged down
etisserant@0:        * in something else...
etisserant@0:        */
etisserant@0: 	// NOTE: We are leaking memory, as the integer will never get free'd!!
etisserant@0:       integer_c *integer = new integer_c("1");
etisserant@0: 	// NOTE: We are leaking memory, as the array_initial_elements will never get free'd!!
etisserant@0:       array_initial_elements_c *array_initial_elements = new array_initial_elements_c(integer, init_value);
etisserant@0: 	// NOTE: We are leaking memory, as the array_initial_elements_list will never get free'd!!
etisserant@0:       array_initial_elements_list_c *array_initial_elements_list  = new array_initial_elements_list_c();
etisserant@0:       array_initial_elements_list->add_element(array_initial_elements);
etisserant@0:       return (void *)array_initial_elements_list;
etisserant@0:     }
etisserant@0: /* helper symbol for array_specification */
etisserant@0: /* array_subrange_list ',' subrange */
etisserant@0:     void *visit(array_subrange_list_c *symbol)	{ERROR; return NULL;}
etisserant@0: /* array_initialization:  '[' array_initial_elements_list ']' */
etisserant@0: /* helper symbol for array_initialization */
etisserant@0: /* array_initial_elements_list ',' array_initial_elements */
etisserant@0:     void *visit(array_initial_elements_list_c *symbol)	{ERROR; return NULL;}
etisserant@0: /* integer '(' [array_initial_element] ')' */
etisserant@0: /* array_initial_element may be NULL ! */
etisserant@0:     void *visit(array_initial_elements_c *symbol)	{ERROR; return NULL;}
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0:     /* TODO: from this point forward... */
etisserant@0: 
etisserant@0: /*  structure_type_name ':' structure_specification */
etisserant@0:     void *visit(structure_type_declaration_c *symbol) {return NULL;}
etisserant@0: /* structure_type_name ASSIGN structure_initialization */
etisserant@0: /* structure_initialization may be NULL ! */
etisserant@0:     void *visit(initialized_structure_c *symbol)	{return NULL;}
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 NULL;}
etisserant@0: /*  structure_element_name ':' *_spec_init */
etisserant@0:     void *visit(structure_element_declaration_c *symbol)	{return NULL;}
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)	{return NULL;}
etisserant@0: /*  structure_element_name ASSIGN value */
etisserant@0:     void *visit(structure_element_initialization_c *symbol)	{return NULL;}
etisserant@0: /*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */
etisserant@0: /*
etisserant@0:  * NOTE:
etisserant@0:  * (Summary: Contrary to what is expected, the
etisserant@0:  *           string_type_declaration_c is not used to store
etisserant@0:  *           simple string type declarations that do not include
etisserant@0:  *           size limits.
etisserant@0:  *           For e.g.:
etisserant@0:  *             str1_type: STRING := "hello!"
etisserant@0:  *           will be stored in a simple_type_declaration_c
etisserant@0:  *           instead of a string_type_declaration_c.
etisserant@0:  *           The following:
etisserant@0:  *             str2_type: STRING [64] := "hello!"
etisserant@0:  *           will be stored in a sring_type_declaration_c
etisserant@0:  *
etisserant@0:  *           Read on for why this is done...
etisserant@0:  * End Summary)
etisserant@0:  *
etisserant@0:  * According to the spec, the valid construct
etisserant@0:  * TYPE new_str_type : STRING := "hello!"; END_TYPE
etisserant@0:  * has two possible routes to type_declaration...
etisserant@0:  *
etisserant@0:  * Route 1:
etisserant@0:  * type_declaration: single_element_type_declaration
etisserant@0:  * single_element_type_declaration: simple_type_declaration
etisserant@0:  * simple_type_declaration: identifier ':' simple_spec_init
etisserant@0:  * simple_spec_init: simple_specification ASSIGN constant
etisserant@0:  * (shift:  identifier <- 'new_str_type')
etisserant@0:  * simple_specification: elementary_type_name
etisserant@0:  * elementary_type_name: STRING
etisserant@0:  * (shift: elementary_type_name <- STRING)
etisserant@0:  * (reduce: simple_specification <- elementary_type_name)
etisserant@0:  * (shift: constant <- "hello!")
etisserant@0:  * (reduce: simple_spec_init: simple_specification ASSIGN constant)
etisserant@0:  * (reduce: ...)
etisserant@0:  *
etisserant@0:  *
etisserant@0:  * Route 2:
etisserant@0:  * type_declaration: string_type_declaration
etisserant@0:  * string_type_declaration: identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init
etisserant@0:  * (shift:  identifier <- 'new_str_type')
etisserant@0:  * elementary_string_type_name: STRING
etisserant@0:  * (shift: elementary_string_type_name <- STRING)
etisserant@0:  * (shift: string_type_declaration_size <-  empty )
etisserant@0:  * string_type_declaration_init: ASSIGN character_string
etisserant@0:  * (shift: character_string <- "hello!")
etisserant@0:  * (reduce: string_type_declaration_init <- ASSIGN character_string)
etisserant@0:  * (reduce: string_type_declaration <- identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init )
etisserant@0:  * (reduce: type_declaration <- string_type_declaration)
etisserant@0:  *
etisserant@0:  *
etisserant@0:  * At first glance it seems that removing route 1 would make
etisserant@0:  * the most sense. Unfortunately the construct 'simple_spec_init'
etisserant@0:  * shows up multiple times in other rules, so changing this construct
etisserant@0:  * would also mean changing all the rules in which it appears.
etisserant@0:  * I (Mario) therefore chose to remove route 2 instead. This means
etisserant@0:  * that the above declaration gets stored in a
etisserant@0:  * simple_type_declaration_c, and not in a string_type_declaration_c
etisserant@0:  * as would be expected!
etisserant@0:  */
etisserant@0: /*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */
etisserant@0: #if 0
etisserant@0: SYM_REF4(string_type_declaration_c,	string_type_name,
etisserant@0: 					elementary_string_type_name,
etisserant@0: 					string_type_declaration_size,
etisserant@0: 					string_type_declaration_init) /* may be == NULL! */
etisserant@0: #endif
etisserant@0:     void *visit(string_type_declaration_c *symbol)	{return NULL;}
etisserant@0: };
etisserant@0: 
etisserant@0: type_initial_value_c	*type_initial_value_c::_instance = NULL;
etisserant@0: real_c			*type_initial_value_c::real_0 = NULL;
etisserant@0: integer_c		*type_initial_value_c::integer_0 = NULL;
etisserant@0: integer_c		*type_initial_value_c::integer_1 = NULL;
etisserant@0: boolean_literal_c	*type_initial_value_c::bool_0 = NULL;
etisserant@0: date_literal_c	*type_initial_value_c::date_literal_0 = NULL;
etisserant@0: daytime_c	*type_initial_value_c::daytime_literal_0 = NULL;
etisserant@0: duration_c	*type_initial_value_c::time_0 = NULL;
etisserant@0: date_c	*type_initial_value_c::date_0 = NULL;
etisserant@0: time_of_day_c	*type_initial_value_c::tod_0 = NULL;
etisserant@0: date_and_time_c	*type_initial_value_c::dt_0 = NULL;
etisserant@0: single_byte_character_string_c *type_initial_value_c::string_0 = NULL;
etisserant@0: double_byte_character_string_c *type_initial_value_c::wstring_0 = NULL;
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: 
etisserant@0: