diff -r 64334c5a00b1 -r 38d6eb056260 stage4/generate_c/type_initial_value.cc
--- a/stage4/generate_c/type_initial_value.cc	Sat May 30 16:42:41 2009 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,386 +0,0 @@
-/*
- * (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 default initial value of a type declaration.
- *
- * This is part of the 4th stage that generates
- * a c++ source program equivalent to the IL and ST
- * code.
- */
-
-
-
-
-//#include <stdio.h>  /* required for NULL */
-//#include <string>
-//#include <iostream>
-
-//#include "../../util/symtable.hh"
-
-//#include "generate_c.hh"
-
-
-
-
-
-/* Given a type definition declration, determine its default
- * initial value. Note that types based on other types
- * may have to iterate through each type it is based on
- * to determine the initial value.
- * E.g.
- *  TYPE
- *    A_t : INT := 10;
- *    B_t : A_t := 20;
- *    C_t : B_t;
- *    D_t : C_t := 40;
- *  END_TYPE
- * Where the default initial value for C_t is 20!
- */
-/* NOTE: The main program only needs one instance of
- *       this class of object. This class
- *       is therefore a singleton.
- */
-class type_initial_value_c : public null_visitor_c {
-  private:
-    static type_initial_value_c *_instance;
-    /* constants for the default values of elementary data types... */
-    static real_c		*real_0;
-    static integer_c		*integer_0, *integer_1;
-    static boolean_literal_c	*bool_0;
-    static date_literal_c	*date_literal_0;
-    static daytime_c		*daytime_literal_0;
-    static duration_c		*time_0;
-    static date_c		*date_0;
-    static time_of_day_c	*tod_0;
-    static date_and_time_c	*dt_0;
-    static single_byte_character_string_c *string_0;
-    static double_byte_character_string_c *wstring_0;
-
-  public:
-    static type_initial_value_c *instance(void) {
-      if (_instance != NULL)
-        return _instance;
-
-      _instance = new type_initial_value_c;
-
-      real_0 = new real_c("0");
-      integer_0 = new integer_c("0");
-      integer_1 = new integer_c("1");
-      bool_0 = new boolean_literal_c(new bool_type_name_c(),new boolean_false_c());
-      /* FIXME: Our current implementation only allows dates from 1970 onwards,
-       * but the standard defines the date 0001-01-01 as the default value
-       * for the DATE data type. Untill we fix our implementation, we use 1970-01-01
-       * as our default value!!
-       */
-//      date_literal_0 =  new date_literal_c(integer_1, integer_1, integer_1);
-      date_literal_0 =  new date_literal_c(new integer_c("1970"), integer_1, integer_1);
-      daytime_literal_0 = new daytime_c(integer_0, integer_0, real_0);
-      time_0 = new duration_c(NULL, new seconds_c(integer_0, NULL));  // T#0S
-      date_0 = new date_c(date_literal_0);  //  D#0001-01-01
-      tod_0 = new time_of_day_c(daytime_literal_0);  //  TOD#00:00:00
-      dt_0 = new date_and_time_c(date_literal_0, daytime_literal_0);  //  DT#0001-01-01-00:00:00
-      string_0  = new single_byte_character_string_c("''");
-      wstring_0 = new double_byte_character_string_c("\"\"");
-
-      return _instance;
-    }
-
-  protected:
-    type_initial_value_c(void) {}
-
-  public:
-    symbol_c *get(identifier_c *type_name) {
-      TRACE("type_initial_value_c::get(): called ");
-      return (symbol_c *)type_name->accept(*this);
-    }
-
-
-  private:
-    void *handle_type_spec(symbol_c *base_type_name, symbol_c *type_spec_init) {
-      if (type_spec_init != NULL)
-         return type_spec_init;
-       /* no initial value specified, so we return
-       * the initial value of the type this type is based on...
-        */
-      return base_type_name->accept(*this);
-    }
-
-  public:
-    void *visit(identifier_c *type_name) {
-      /* look up the type declaration... */
-      symbol_c *type_decl = type_symtable.find_value(type_name);
-      if (type_decl == type_symtable.end_value())
-        /* Type declaration not found!! */
-	/* NOTE: Variables declared out of function block 'data types',
-	 *    for eg:  VAR  timer: TON; END_VAR
-	 * do not have a default value, so (TON) will never be found in the
-	 * type symbol table. This means we cannot simply consider this
-	 * an error and abort, but must rather return a NULL.
-	 */
-	return NULL;
-
-      return type_decl->accept(*this);
-    }
-
-/***********************************/
-/* B 1.3.1 - Elementary Data Types */
-/***********************************/
-    void *visit(time_type_name_c *symbol)	{return (void *)time_0;}
-    void *visit(bool_type_name_c *symbol)	{return (void *)bool_0;}
-    void *visit(sint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(int_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(dint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(lint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(usint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(uint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(udint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(ulint_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(real_type_name_c *symbol)	{return (void *)real_0;}
-    void *visit(lreal_type_name_c *symbol)	{return (void *)real_0;}
-    void *visit(date_type_name_c *symbol)	{return (void *)date_0;}
-    void *visit(tod_type_name_c *symbol)	{return (void *)tod_0;}
-    void *visit(dt_type_name_c *symbol)		{return (void *)dt_0;}
-    void *visit(byte_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(word_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(dword_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(lword_type_name_c *symbol)	{return (void *)integer_0;}
-    void *visit(string_type_name_c *symbol)	{return (void *)string_0;}
-    void *visit(wstring_type_name_c *symbol)	{return (void *)wstring_0;}
-
-/********************************/
-/* B 1.3.3 - Derived data types */
-/********************************/
-/*  simple_type_name ':' simple_spec_init */
-    void *visit(simple_type_declaration_c *symbol) {
-      return symbol->simple_spec_init->accept(*this);
-    }
-/* simple_specification ASSIGN constant */
-    void *visit(simple_spec_init_c *symbol) {
-      return handle_type_spec(symbol->simple_specification, symbol->constant);
-    }
-/*  subrange_type_name ':' subrange_spec_init */
-    void *visit(subrange_type_declaration_c *symbol) {
-      return symbol->subrange_spec_init->accept(*this);
-    }
-/* subrange_specification ASSIGN signed_integer */
-    void *visit(subrange_spec_init_c *symbol) {
-      return handle_type_spec(symbol->subrange_specification, symbol->signed_integer);
-    }
-/*  integer_type_name '(' subrange')' */
-    void *visit(subrange_specification_c *symbol) {
-     /* if no initial value explicitly given, then use the lowest value of the subrange */
-      if (symbol->subrange != NULL)
-        return symbol->subrange->accept(*this);
-      else
-        return symbol->integer_type_name->accept(*this);
-    }
-/*  signed_integer DOTDOT signed_integer */
-    void *visit(subrange_c *symbol)	{return symbol->lower_limit;}
-/*  enumerated_type_name ':' enumerated_spec_init */
-    void *visit(enumerated_type_declaration_c *symbol) {
-      return symbol->enumerated_spec_init->accept(*this);
-    }
-/* enumerated_specification ASSIGN enumerated_value */
-    void *visit(enumerated_spec_init_c *symbol) {
-      return handle_type_spec(symbol->enumerated_specification, symbol->enumerated_value);
-    }
-/* helper symbol for enumerated_specification->enumerated_spec_init */
-/* enumerated_value_list ',' enumerated_value */
-    void *visit(enumerated_value_list_c *symbol) {
-     /* if no initial value explicitly given, then use the lowest value of the subrange */
-      return (void *)symbol->elements[0];
-    }
-/* enumerated_type_name '#' identifier */
-// SYM_REF2(enumerated_value_c, type, value)
-    void *visit(enumerated_value_c *symbol)	{ERROR; return NULL;}
-/*  identifier ':' array_spec_init */
-    void *visit(array_type_declaration_c *symbol) {
-      return symbol->array_spec_init->accept(*this);
-    }
-/* array_specification [ASSIGN array_initialization} */
-/* array_initialization may be NULL ! */
-    void *visit(array_spec_init_c *symbol) {
-      return handle_type_spec(symbol->array_specification, symbol->array_initialization);
-    }
-/* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */
-    void *visit(array_specification_c *symbol)	{
-      //symbol_c *init_value = (symbol_c *)symbol->non_generic_type_name->accept(*this);
-
-      /* Now build a array_initial_elements_list_c list, and populate it
-       * with 1 element of the array_initial_elements_c class
-       */
-      /* The array_initial_elements_c will contain a reference to the init_value,
-       * and another constant representing the number of elements in the array.
-       * In essence, we are building the equivilant of the following ST/IL code:
-       *    New_array_t : ARRAY [1..30, 51..60] of INT := [40(XXX)];
-       * from the user given code
-       *    New_array_t : ARRAY [1..30, 51..60] of INT;
-       * and replacing XXX with the default initial value of INT.
-       */
-      /* now we need to determine the number of elements in the array... */
-      /* Easier said than done, as the array may have a list of subranges, as in the
-       * example given above!!
-       */
-      /* TODO !!!!!*/
-      /* For now, just assume an array with 1 element.
-       * I (Mario) want to finish off this part of the code before getting boged down
-       * in something else...
-       */
-	// NOTE: We are leaking memory, as the integer will never get free'd!!
-      //integer_c *integer = new integer_c("1");
-	// NOTE: We are leaking memory, as the array_initial_elements will never get free'd!!
-      //array_initial_elements_c *array_initial_elements = new array_initial_elements_c(integer, init_value);
-	// NOTE: We are leaking memory, as the array_initial_elements_list will never get free'd!!
-      array_initial_elements_list_c *array_initial_elements_list  = new array_initial_elements_list_c();
-      //array_initial_elements_list->add_element(array_initial_elements);
-      return array_initial_elements_list;
-    }
-/* helper symbol for array_specification */
-/* array_subrange_list ',' subrange */
-    void *visit(array_subrange_list_c *symbol)	{ERROR; return NULL;}
-/* array_initialization:  '[' array_initial_elements_list ']' */
-/* helper symbol for array_initialization */
-/* array_initial_elements_list ',' array_initial_elements */
-    void *visit(array_initial_elements_list_c *symbol)	{ERROR; return NULL;}
-/* integer '(' [array_initial_element] ')' */
-/* array_initial_element may be NULL ! */
-    void *visit(array_initial_elements_c *symbol)	{ERROR; return NULL;}
-
-
-
-    /* TODO: from this point forward... */
-
-/*  structure_type_name ':' structure_specification */
-    void *visit(structure_type_declaration_c *symbol) {return NULL;}
-/* structure_type_name ASSIGN structure_initialization */
-/* structure_initialization may be NULL ! */
-    void *visit(initialized_structure_c *symbol)	{
-      return handle_type_spec(symbol->structure_type_name, symbol->structure_initialization);
-    }
-/* helper symbol for structure_declaration */
-/* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */
-/* structure_element_declaration_list structure_element_declaration ';' */
-    void *visit(structure_element_declaration_list_c *symbol)	{
-      structure_element_initialization_list_c *structure_element_initialization_list = new structure_element_initialization_list_c();
-      return structure_element_initialization_list;
-    }
-/*  structure_element_name ':' *_spec_init */
-    void *visit(structure_element_declaration_c *symbol)	{return NULL;}
-/* helper symbol for structure_initialization */
-/* structure_initialization: '(' structure_element_initialization_list ')' */
-/* structure_element_initialization_list ',' structure_element_initialization */
-    void *visit(structure_element_initialization_list_c *symbol)	{return NULL;}
-/*  structure_element_name ASSIGN value */
-    void *visit(structure_element_initialization_c *symbol)	{return NULL;}
-/*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */
-/*
- * NOTE:
- * (Summary: Contrary to what is expected, the
- *           string_type_declaration_c is not used to store
- *           simple string type declarations that do not include
- *           size limits.
- *           For e.g.:
- *             str1_type: STRING := "hello!"
- *           will be stored in a simple_type_declaration_c
- *           instead of a string_type_declaration_c.
- *           The following:
- *             str2_type: STRING [64] := "hello!"
- *           will be stored in a sring_type_declaration_c
- *
- *           Read on for why this is done...
- * End Summary)
- *
- * According to the spec, the valid construct
- * TYPE new_str_type : STRING := "hello!"; END_TYPE
- * has two possible routes to type_declaration...
- *
- * Route 1:
- * type_declaration: single_element_type_declaration
- * single_element_type_declaration: simple_type_declaration
- * simple_type_declaration: identifier ':' simple_spec_init
- * simple_spec_init: simple_specification ASSIGN constant
- * (shift:  identifier <- 'new_str_type')
- * simple_specification: elementary_type_name
- * elementary_type_name: STRING
- * (shift: elementary_type_name <- STRING)
- * (reduce: simple_specification <- elementary_type_name)
- * (shift: constant <- "hello!")
- * (reduce: simple_spec_init: simple_specification ASSIGN constant)
- * (reduce: ...)
- *
- *
- * Route 2:
- * type_declaration: string_type_declaration
- * string_type_declaration: identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init
- * (shift:  identifier <- 'new_str_type')
- * elementary_string_type_name: STRING
- * (shift: elementary_string_type_name <- STRING)
- * (shift: string_type_declaration_size <-  empty )
- * string_type_declaration_init: ASSIGN character_string
- * (shift: character_string <- "hello!")
- * (reduce: string_type_declaration_init <- ASSIGN character_string)
- * (reduce: string_type_declaration <- identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init )
- * (reduce: type_declaration <- string_type_declaration)
- *
- *
- * At first glance it seems that removing route 1 would make
- * the most sense. Unfortunately the construct 'simple_spec_init'
- * shows up multiple times in other rules, so changing this construct
- * would also mean changing all the rules in which it appears.
- * I (Mario) therefore chose to remove route 2 instead. This means
- * that the above declaration gets stored in a
- * simple_type_declaration_c, and not in a string_type_declaration_c
- * as would be expected!
- */
-/*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */
-#if 0
-SYM_REF4(string_type_declaration_c,	string_type_name,
-					elementary_string_type_name,
-					string_type_declaration_size,
-					string_type_declaration_init) /* may be == NULL! */
-#endif
-    void *visit(string_type_declaration_c *symbol)	{return NULL;}
-};
-
-type_initial_value_c	*type_initial_value_c::_instance = NULL;
-real_c			*type_initial_value_c::real_0 = NULL;
-integer_c		*type_initial_value_c::integer_0 = NULL;
-integer_c		*type_initial_value_c::integer_1 = NULL;
-boolean_literal_c	*type_initial_value_c::bool_0 = NULL;
-date_literal_c	*type_initial_value_c::date_literal_0 = NULL;
-daytime_c	*type_initial_value_c::daytime_literal_0 = NULL;
-duration_c	*type_initial_value_c::time_0 = NULL;
-date_c	*type_initial_value_c::date_0 = NULL;
-time_of_day_c	*type_initial_value_c::tod_0 = NULL;
-date_and_time_c	*type_initial_value_c::dt_0 = NULL;
-single_byte_character_string_c *type_initial_value_c::string_0 = NULL;
-double_byte_character_string_c *type_initial_value_c::wstring_0 = NULL;
-
-
-
-
-
-