adding some comments.
/*
* (c) 2007 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)
*
*/
/*
* The private interface to stage1_2.cc
*/
/* !!! WARNING !!!
*
* Whoever includes this file (stage1_2_priv.hh) will need
* to first inlcude iec.y.hh !!
*
* Read other comments further down to understand why we don't
* include iec.y.hh in this file.
*/
/* file with the declarations of symbol tables... */
#include "../util/symtable.hh"
/*
* This file includes the interface through which the lexical parser (stage 1 - flex)
* and the syntax analyser (stage 2 - bison) interact between themselves.
*
* This is mostly through direct access to shared global variables, however some
* of the global variables will only be accessed through some accessor functions.
*
* This file also includes some utility functions (strdupX() ) that are both used
* in the lexical and syntax analysers.
*/
/*********************************************/
/* print the include file stack to stderr... */
/*********************************************/
/* This is a service that flex provides to bison... */
void print_include_stack(void);
/**************************************/
/* The name of the file being parsed. */
/**************************************/
/* The name of the file currently being parsed...
* Note that flex accesses and updates this global variable
* apropriately whenever it comes across an (*#include <filename> *)
* directive...
* ... and bison will use it when producing error messages.
* Note that bison also sets this variable correctly to the first
* file being parsed.
*/
extern const char *current_filename;
/****************************************************/
/* Controlling the entry to the body_state in flex. */
/****************************************************/
void cmd_goto_body_state(void);
int get_goto_body_state(void);
void rst_goto_body_state(void);
/*************************************************************/
/* Controlling the entry to the sfc_qualifier_state in flex. */
/*************************************************************/
void cmd_goto_sfc_qualifier_state(void);
int get_goto_sfc_qualifier_state(void);
void rst_goto_sfc_qualifier_state(void);
/*********************************************************/
/* Controlling the entry to the task_init_state in flex. */
/*********************************************************/
void cmd_goto_task_init_state(void);
int get_goto_task_init_state(void);
void rst_goto_task_init_state(void);
/****************************************************************/
/* Returning to state in flex previously pushed onto the stack. */
/****************************************************************/
void cmd_pop_state(void);
int get_pop_state(void);
void rst_pop_state(void);
/*********************************/
/* The global symbol tables... */
/*********************************/
/* NOTE: only accessed indirectly by the lexical parser (flex)
* through the function get_identifier_token()
*/
/* NOTE: BOGUS_TOKEN_ID is defined in the bison generated file iec.y.hh.
* We need this constant defined before we can declare the symbol tables.
* However, we cannot #include "iec.y.hh" in this file (stage1_2_priv.hh) directly
* because of the way bison ver. 2.3 is copying all declarations in the prologue
* of iec.y to the iec.y.hh file (including an #include stage1_2_priv.hh).
* So, if we were to include "iec.y.hh" here, we would get a circular include.
* All this means that whoever includes this file (stage1_2_priv.hh) will need
* to take care to first inlcude iec.y.hh !!
*/
/* A symbol table to store all the library elements */
/* e.g.: <function_name , function_decl>
* <fb_name , fb_decl>
* <type_name , type_decl>
* <program_name , program_decl>
* <configuration_name , configuration_decl>
*/
extern symtable_c<int, BOGUS_TOKEN_ID> library_element_symtable;
/* A symbol table to store the declared variables of
* the function currently being parsed...
*/
extern symtable_c<int, BOGUS_TOKEN_ID> variable_name_symtable;
/* Function only called from within flex!
*
* search for a symbol in either of the two symbol tables
* declared above, and return the token id of the first
* symbol found.
* Searches first in the variables, and only if not found
* does it continue searching in the library elements
*/
int get_identifier_token(const char *identifier_str);
/************************/
/* Utility Functions... */
/************************/
/* Join two strings together. Allocate space with malloc(3). */
char *strdup2(const char *a, const char *b);
/* Join three strings together. Allocate space with malloc(3). */
char *strdup3(const char *a, const char *b, const char *c);