/*
* (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)
*
*/
/*
* Function parameter iterator.
* Iterate through the in/out parameters of a function declaration.
* Function blocks are also suported.
*
* 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"
#include "../../absyntax/visitor.hh"
/* given a function_declaration_c, iterate through each
* function in/out/inout parameter, returning the name
* of each parameter...function_param_iterator_c
*/
class function_param_iterator_c : public null_visitor_c {
public:
/* A type to specify the type of parameter.
* VAR_INPUT => direction_in
* VAR_OUTPUT => direction_out
* VAR_IN_OUT => direction_inout
* VAR_EXTERNAL => direction_extref
*
* Note that VAR_EXTERNAL declares variables that are in reality references
* to global variables. This is used only inside programs!
* These references to external variables must be correctly initialised to refer
* to the correct global variable. Note that the user may define which variable is to be
* referenced in a CONFIGURATION, and that different instantiations of a program
* may have the same external variable reference diffenrent global variables!
* The references must therefore be correctly initialised when the program instance
* is created. This may be done by the PROGRAM class constructor since the ST and IL
* languages do not allow the VAR_EXTERNAL reference to change at runtime
* for a specific instance.
*
* We therefore need to call a PROGRAM class constructor with the variables
* that should be refernced by the VAR_EXTERNAL variables. The direction_extref will
* be used to identify these parameters!
*/
typedef enum {direction_in, direction_out, direction_inout, direction_extref} param_direction_t ;
private:
/* a pointer to the function_block_declaration_c
* or function_declaration_c currently being analysed.
*/
symbol_c *f_decl;
int next_param, param_count;
identifier_c *current_param_name;
symbol_c *current_param_type;
symbol_c *current_param_default_value;
param_direction_t current_param_direction;
private:
void* handle_param_list(list_c *list) {
if (next_param <= param_count + list->n)
return list->elements[next_param - param_count - 1];
/* the desired param is not on this list... */
param_count += list->n;
return NULL;
}
void* handle_single_param(symbol_c *var_name) {
param_count++;
if (next_param == param_count)
return var_name;
/* not yet the desired param... */
return NULL;
}
void* iterate_list(list_c *list) {
void *res;
for (int i = 0; i < list->n; i++) {
res = list->elements[i]->accept(*this);
if (res != NULL)
return res;
}
return NULL;
}
public:
/* start off at the first parameter once again... */
void reset(void) {
next_param = param_count = 0;
current_param_name = NULL;
current_param_type = current_param_default_value = NULL;
}
/* initialise the iterator object.
* We must be given a reference to the function declaration
* that will be analysed...
*/
function_param_iterator_c(function_declaration_c *f_decl) {
this->f_decl = f_decl;
reset();
}
/* initialise the iterator object.
* We must be given a reference to the function block declaration
* that will be analysed...
*/
function_param_iterator_c(function_block_declaration_c *fb_decl) {
this->f_decl = fb_decl;
reset();
}
/* initialise the iterator object.
* We must be given a reference to the program declaration
* that will be analysed...
*/
function_param_iterator_c(program_declaration_c *p_decl) {
this->f_decl = p_decl;
reset();
}
/* Skip to the next parameter. After object creation,
* the object references on parameter _before_ the first, so
* this function must be called once to get the object to
* reference the first parameter...
*
* Returns the parameter's name!
*/
identifier_c *next(void) {
void *res;
param_count = 0;
next_param++;
res = f_decl->accept(*this);
if (res == NULL)
return NULL;
symbol_c *sym = (symbol_c *)res;
identifier_c *identifier = dynamic_cast<identifier_c *>(sym);
if (identifier == NULL)
ERROR;
current_param_name = identifier;
return current_param_name;
}
/* Returns the currently referenced parameter's default value,
* or NULL if none is specified in the function declrataion itself.
*/
symbol_c *default_value(void) {
return current_param_default_value;
}
/* Returns the currently referenced parameter's type name. */
symbol_c *param_type(void) {
return current_param_type;
}
/* Returns the currently referenced parameter's data passing direction.
* i.e. VAR_INPUT, VAR_OUTPUT or VAR_INOUT
*/
param_direction_t param_direction(void) {
return current_param_direction;
}
/******************************************/
/* B 1.4.3 - Declaration & Initialisation */
/******************************************/
void *visit(input_declarations_c *symbol) {
TRACE("input_declarations_c");
current_param_direction = direction_in;
return symbol->input_declaration_list->accept(*this);
}
void *visit(input_declaration_list_c *symbol) {TRACE("input_declaration_list_c"); return iterate_list(symbol);}
void *visit(edge_declaration_c *symbol) {TRACE("edge_declaration_c"); return symbol->var1_list->accept(*this);}
#if 0
/* var1_list ':' array_spec_init */
SYM_REF2(array_var_init_decl_c, var1_list, array_spec_init)
/* var1_list ':' initialized_structure */
SYM_REF2(structured_var_init_decl_c, var1_list, initialized_structure)
/* name_list ':' function_block_type_name ASSIGN structure_initialization */
/* structure_initialization -> may be NULL ! */
SYM_REF4(fb_name_decl_c, fb_name_list, function_block_type_name, structure_initialization, unused)
/* name_list ',' fb_name */
SYM_LIST(fb_name_list_c)
#endif
void *visit(output_declarations_c *symbol) {
TRACE("output_declarations_c");
current_param_direction = direction_out;
return symbol->var_init_decl_list->accept(*this);
}
void *visit(input_output_declarations_c *symbol) {
TRACE("input_output_declarations_c");
current_param_direction = direction_inout;
return symbol->var_declaration_list->accept(*this);
}
void *visit(var_declaration_list_c *symbol) {TRACE("var_declaration_list_c"); return iterate_list(symbol);}
#if 0
/* var1_list ':' array_specification */
SYM_REF2(array_var_declaration_c, var1_list, array_specification)
/* var1_list ':' structure_type_name */
SYM_REF2(structured_var_declaration_c, var1_list, structure_type_name)
#endif
/* VAR [CONSTANT] var_init_decl_list END_VAR */
void *visit(var_declarations_c *symbol) {TRACE("var_declarations_c"); return NULL;}
#if 0
/* VAR RETAIN var_init_decl_list END_VAR */
SYM_REF2(retentive_var_declarations_c, var_init_decl_list, unused)
/* VAR [CONSTANT|RETAIN|NON_RETAIN] located_var_decl_list END_VAR */
/* option -> may be NULL ! */
SYM_REF2(located_var_declarations_c, option, located_var_decl_list)
/* helper symbol for located_var_declarations */
/* located_var_decl_list located_var_decl ';' */
SYM_LIST(located_var_decl_list_c)
/* [variable_name] location ':' located_var_spec_init */
/* variable_name -> may be NULL ! */
SYM_REF4(located_var_decl_c, variable_name, location, located_var_spec_init, unused)
#endif
/*| VAR_EXTERNAL [CONSTANT] external_declaration_list END_VAR */
/* option -> may be NULL ! */
// SYM_REF2(external_var_declarations_c, option, external_declaration_list)
void *visit(external_var_declarations_c *symbol) {
TRACE("external_var_declarations_c");
current_param_direction = direction_extref;
return symbol->external_declaration_list->accept(*this);
}
/* helper symbol for external_var_declarations */
/*| external_declaration_list external_declaration';' */
// SYM_LIST(external_declaration_list_c)
void *visit(external_declaration_list_c *symbol) {TRACE("external_declaration_list_c"); return iterate_list(symbol);}
/* global_var_name ':' (simple_specification|subrange_specification|enumerated_specification|array_specification|prev_declared_structure_type_name|function_block_type_name */
//SYM_REF2(external_declaration_c, global_var_name, specification)
void *visit(external_declaration_c *symbol) {
TRACE("external_declaration_c");
/* It is OK to store these values in the current_param_XXX
* variables, because if the desired parameter is not in the
* variable list we will be analysing, the current_param_XXXX
* variables will get overwritten when we visit the next
* var1_init_decl_c list!
*/
current_param_default_value = spec_init_sperator_c::get_init(symbol->specification);
current_param_type = spec_init_sperator_c::get_spec(symbol->specification);
return handle_single_param(symbol->global_var_name);
}
#if 0
/*| VAR_GLOBAL [CONSTANT|RETAIN] global_var_decl_list END_VAR */
/* option -> may be NULL ! */
SYM_REF2(global_var_declarations_c, option, global_var_decl_list)
/* helper symbol for global_var_declarations */
/*| global_var_decl_list global_var_decl ';' */
SYM_LIST(global_var_decl_list_c)
/*| global_var_spec ':' [located_var_spec_init|function_block_type_name] */
/* type_specification ->may be NULL ! */
SYM_REF2(global_var_decl_c, global_var_spec, type_specification)
/*| global_var_name location */
SYM_REF2(global_var_spec_c, global_var_name, location)
/* AT direct_variable */
SYM_REF2(location_c, direct_variable, unused)
/*| global_var_list ',' global_var_name */
SYM_LIST(global_var_list_c)
/* var1_list ':' single_byte_string_spec */
SYM_REF2(single_byte_string_var_declaration_c, var1_list, single_byte_string_spec)
/* STRING ['[' integer ']'] [ASSIGN single_byte_character_string] */
/* integer ->may be NULL ! */
/* single_byte_character_string ->may be NULL ! */
SYM_REF2(single_byte_string_spec_c, integer, single_byte_character_string)
/* var1_list ':' double_byte_string_spec */
SYM_REF2(double_byte_string_var_declaration_c, var1_list, double_byte_string_spec)
/* WSTRING ['[' integer ']'] [ASSIGN double_byte_character_string] */
/* integer ->may be NULL ! */
/* double_byte_character_string ->may be NULL ! */
SYM_REF2(double_byte_string_spec_c, integer, double_byte_character_string)
/*| VAR [RETAIN|NON_RETAIN] incompl_located_var_decl_list END_VAR */
/* option ->may be NULL ! */
SYM_REF2(incompl_located_var_declarations_c, option, incompl_located_var_decl_list)
/* helper symbol for incompl_located_var_declarations */
/*| incompl_located_var_decl_list incompl_located_var_decl ';' */
SYM_LIST(incompl_located_var_decl_list_c)
/* variable_name incompl_location ':' var_spec */
SYM_REF4(incompl_located_var_decl_c, variable_name, incompl_location, var_spec, unused)
/* AT incompl_location_token */
SYM_TOKEN(incompl_location_c)
#endif
void *visit(var1_init_decl_c *symbol) {
TRACE("var1_init_decl_c");
/* It is OK to store these values in the current_param_XXX
* variables, because if the desired parameter is not in the
* variable list we will be analysing, the current_param_XXXX
* variables will get overwritten when we visit the next
* var1_init_decl_c list!
*/
current_param_default_value = spec_init_sperator_c::get_init(symbol->spec_init);
current_param_type = spec_init_sperator_c::get_spec(symbol->spec_init);
return symbol->var1_list->accept(*this);
}
void *visit(var1_list_c *symbol) {
TRACE("var1_list_c");
return handle_param_list(symbol);
}
void *visit(var_init_decl_list_c *symbol) {TRACE("var_init_decl_list_c"); return iterate_list(symbol);}
/***********************/
/* B 1.5.1 - Functions */
/***********************/
void *visit(function_declaration_c *symbol) {TRACE("function_declaration_c"); return symbol->var_declarations_list->accept(*this);}
/* intermediate helper symbol for function_declaration */
void *visit(var_declarations_list_c *symbol) {TRACE("var_declarations_list_c"); return iterate_list(symbol);}
void *visit(function_var_decls_c *symbol) {TRACE("function_var_decls_c"); /* ignore */ return NULL;}
/*****************************/
/* B 1.5.2 - Function Blocks */
/*****************************/
/* FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
void *visit(function_block_declaration_c *symbol) {TRACE("function_block_declaration_c"); return symbol->var_declarations->accept(*this);}
/* intermediate helper symbol for function_declaration */
/* { io_var_declarations | other_var_declarations } */
/*
* NOTE: we re-use the var_declarations_list_c
*/
/* VAR_TEMP temp_var_decl_list END_VAR */
void *visit(temp_var_decls_c *symbol) {TRACE("temp_var_decls_c"); /* ignore */ return NULL;}
void *visit(temp_var_decls_list_c *symbol) {TRACE("temp_var_decls_list_c"); /* ignore */ return NULL;}
/* VAR NON_RETAIN var_init_decl_list END_VAR */
void *visit(non_retentive_var_decls_c *symbol) {TRACE("non_retentive_var_decls_c"); /* ignore */ return NULL;}
/**********************/
/* B 1.5.3 - Programs */
/**********************/
/* PROGRAM program_type_name program_var_declarations_list function_block_body END_PROGRAM */
// SYM_REF4(program_declaration_c, program_type_name, var_declarations, function_block_body, unused)
void *visit(program_declaration_c *symbol) {TRACE("program_declaration_c"); return symbol->var_declarations->accept(*this);}
/* intermediate helper symbol for program_declaration_c */
/* { io_var_declarations | other_var_declarations } */
/*
* NOTE: we re-use the var_declarations_list_c
*/
};