1

/*

    18

 *

    19

 * This code is made available on the understanding that it will not be

    20

 * used in safety-critical situations without a full and competent review.

    21

 */

    22

    23

/*

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 *

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 * Based on the

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 * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)

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 *

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 */

    30

    32

/*

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 * Definition of the Abstract Syntax data structure components

    34

 */

    35

    36

    37

/*

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 * ABSYNTAX.DEF

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 *

    40

 * This generates the parse tree structure used to bind the components

    41

 * identified by Bison in the correct syntax order. At the end of the

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 * Bison analysis the tree is walked in a sequential fashion generating

    43

 * the relavent code.

    44

 */

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/*****************************************************************/

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/*****************************************************************/

    53

/*****************************************************************/

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/*****************************************************************/

    55

/*                                                               */

    56

/*      safe<xxxxxx> Symbols are defined in:                     */

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/*      PLCopen - Technical Committee 5                          */

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/*      Safety Software Technical Specification,                 */

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/*      Part 1: Concepts and Function Blocks,                    */

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/*      Version 1.0 – Official Release - 2006-01-31              */

    61

/*                                                               */

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*                                                               */

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/*             Symbols defined in:                               */

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/*      FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)          */

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/*                                                               */

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

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/*****************************************************************/

    84

    85

/* Based on the                                    */

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/* FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10) */

    87

    88

    89

/* EN/ENO */

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/* NOTE we store 'EN' and 'ENO' tokens in an identifier_c

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 *      as they may be used as variables, and it is much easier 

    92

 *      to handle them (fewer special cases) if we do it that way...

    93

 */

    94

/*

    95

SYM_REF0(en_param_c)

    96

SYM_REF0(eno_param_c)

    97

*/

    98

    99

/***************************/

   100

/* 2.1.6 - Pragmas */

   101

/***************************/

   102

SYM_TOKEN(pragma_c)

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   104

/***************************/

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/* B 0 - Programming Model */

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/***************************/

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SYM_LIST(library_c)

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   109

   110

/*************************/

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/* B.1 - Common elements */

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/*************************/

   113

/*******************************************/

   114

/* B 1.1 - Letters, digits and identifiers */

   115

/*******************************************/

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SYM_TOKEN(identifier_c)

   117

   118

   119

/*********************/

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/* B 1.2 - Constants */

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/*********************/

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   123

/******************************/

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/* B 1.2.1 - Numeric Literals */

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/******************************/

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SYM_TOKEN(real_c)

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SYM_TOKEN(integer_c)

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SYM_TOKEN(binary_integer_c)

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SYM_TOKEN(octal_integer_c)

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SYM_TOKEN(hex_integer_c)

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/* Note:

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 * We do not have signed_integer_c and signed_real_c classes.

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 * These are stored in the parse tree as a integer_c or real_c

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 * preceded by a unary minus operator if they are inside an expression,

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 * or a neg_integer_c and neg_real_c when used outside an ST expression.

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 */

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/* Not required:

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SYM_TOKEN(signed_integer_c)

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SYM_TOKEN(signed_real_c)

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*/

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/* NOTE: literal __values__ are stored directly in classes such as:

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 *          - real_c

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 *          - integer_c

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 *          - binary_integer_c

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 *          - etc...

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 *

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 *       However, for both the real_c and the integer_c, if they are preceded 

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 *       by a '-' negation sign, they are further encapsulated inside 

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 *       a neg_literal_c (i.e. the neg_literal_c will point to the 

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 *       real_c or integer_c with the value being negated.

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 *          neg_literal_c -> integer_literal_c

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 *                OR

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 *          neg_literal_c -> real_literal_c

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 *

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 *      In the semantic verification and code generation stages of the compiler,

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 *      the integer_c is treated as a basic (undefined) data type, since an integer

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 *      constant may be used as a BYTE, BOOLEAN, REAL, etc..., depending on the

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 *      context in which it is used.

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 *      However, an integer_c that is preceded by a '-' may not be used

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 *      as an ANY_BIT data type (BYTE, BOOLEAN, WORD, ...).

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 *      We must therefore be able to determine, holding a simple pointer

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 *      to an integer_c, if that integer_c value is preceded by a '-'.

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 *      However, since the neg_literal_c points to the integer_c, and not

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 *      vice-versa, we can't determine that.

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 *      There are 3 simple ways of working around this:

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 *        - change the order of the pointers: 

   169

 *              have the integer_c and real_c point to the neg_literal_c

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 *        - maintain the order of the pointers, and

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 *              add redundant info to the integer_c and real_c

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 *        - replace the neg_literal_c with two distinc classes

   173

 *              (neg_integer_c and neg_real_c), one for each

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 *              lietral type. This means that we can now treat

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 *              each of these classes as an unknown data type

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 *              just as we do with the integer_c and real_c.

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 *

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 *      The second option is simply ugly.

   179

 *      and the first has a serious drawback: when generating code it is

   180

 *      easier to encapsulate the real or integer values inside prefix

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 *      and postfix symbols (e.g. NEG(<value>) - with postfix ')' )

   182

 *      if we keep the pointer order as is.

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 *

   184

 *      For the above reasoning, we use the third option.

   185

 */  

   186

SYM_REF1(neg_real_c, exp)

   187

SYM_REF1(neg_integer_c, exp)

   188

   189

/* Not required:

   190

SYM_REF2(numeric_literal_c, type, value)

   191

*/

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SYM_REF2(integer_literal_c, type, value)

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SYM_REF2(real_literal_c, type, value)

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SYM_REF2(bit_string_literal_c, type, value)

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/* A typed or untyped boolean literal... */

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/* type may be NULL */

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SYM_REF2(boolean_literal_c, type, value)

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   199

/* helper class for boolean_literal_c */

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SYM_REF0(boolean_true_c)

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/* helper class for boolean_literal_c */

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SYM_REF0(boolean_false_c)

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   205

   206

/*******************************/

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/* B.1.2.2   Character Strings */

   208

/*******************************/

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SYM_TOKEN(double_byte_character_string_c)

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SYM_TOKEN(single_byte_character_string_c)

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   212

   213

/***************************/

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/* B 1.2.3 - Time Literals */

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/***************************/

   216

   217

/************************/

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/* B 1.2.3.1 - Duration */

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/************************/

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SYM_REF0(neg_time_c)

   221

SYM_REF3(duration_c, type_name, neg, interval)

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SYM_TOKEN(fixed_point_c)

   223

SYM_REF2(days_c, days, hours)

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SYM_REF2(hours_c, hours, minutes)

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SYM_REF2(minutes_c, minutes, seconds)

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SYM_REF2(seconds_c, seconds, milliseconds)

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SYM_REF1(milliseconds_c, milliseconds)

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   229

   230

/************************************/

   231

/* B 1.2.3.2 - Time of day and Date */

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/************************************/

   233

SYM_REF2(time_of_day_c, type_name, daytime)

   234

SYM_REF3(daytime_c, day_hour, day_minute, day_second)

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SYM_REF2(date_c, type_name, date_literal)

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SYM_REF3(date_literal_c, year, month, day)

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SYM_REF3(date_and_time_c, type_name, date_literal, daytime)

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   239

   240

/**********************/

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/* B.1.3 - Data types */

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/**********************/

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/***********************************/

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/* B 1.3.1 - Elementary Data Types */

   245

/***********************************/

   246

SYM_REF0(time_type_name_c)

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SYM_REF0(bool_type_name_c)

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SYM_REF0(sint_type_name_c)

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SYM_REF0(int_type_name_c)

   250

SYM_REF0(dint_type_name_c)

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SYM_REF0(lint_type_name_c)

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SYM_REF0(usint_type_name_c)

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SYM_REF0(uint_type_name_c)

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SYM_REF0(udint_type_name_c)

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SYM_REF0(ulint_type_name_c)

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SYM_REF0(real_type_name_c)

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SYM_REF0(lreal_type_name_c)

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SYM_REF0(date_type_name_c)

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SYM_REF0(tod_type_name_c)

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SYM_REF0(dt_type_name_c)

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SYM_REF0(byte_type_name_c)

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SYM_REF0(word_type_name_c)

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SYM_REF0(dword_type_name_c)

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SYM_REF0(lword_type_name_c)

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SYM_REF0(string_type_name_c)

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SYM_REF0(wstring_type_name_c)

   267

   268

  /*****************************************************************/

   269

  /* Keywords defined in "Safety Software Technical Specification" */

   270

  /*****************************************************************/

   271

   272

SYM_REF0(safetime_type_name_c)

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SYM_REF0(safebool_type_name_c)

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SYM_REF0(safesint_type_name_c)

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SYM_REF0(safeint_type_name_c)

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SYM_REF0(safedint_type_name_c)

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SYM_REF0(safelint_type_name_c)

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SYM_REF0(safeusint_type_name_c)

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SYM_REF0(safeuint_type_name_c)

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SYM_REF0(safeudint_type_name_c)

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SYM_REF0(safeulint_type_name_c)

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SYM_REF0(safereal_type_name_c)

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SYM_REF0(safelreal_type_name_c)

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SYM_REF0(safedate_type_name_c)

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SYM_REF0(safetod_type_name_c)

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SYM_REF0(safedt_type_name_c)

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SYM_REF0(safebyte_type_name_c)

   288

SYM_REF0(safeword_type_name_c)

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SYM_REF0(safedword_type_name_c)

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SYM_REF0(safelword_type_name_c)

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SYM_REF0(safestring_type_name_c)

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SYM_REF0(safewstring_type_name_c)

   293

   294

   295

/********************************/

   296

/* B.1.3.2 - Generic data types */

   297

/********************************/

   298

   299

/********************************/

   300

/* B 1.3.3 - Derived data types */

   301

/********************************/

   302

/*  TYPE type_declaration_list END_TYPE */

   303

SYM_REF1(data_type_declaration_c, type_declaration_list)

   304

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/* helper symbol for data_type_declaration */

   306

SYM_LIST(type_declaration_list_c)

   307

   308

/*  simple_type_name ':' simple_spec_init */

   309

SYM_REF2(simple_type_declaration_c, simple_type_name, simple_spec_init)

   310

   311

   312

/* simple_specification ASSIGN constant */

   313

SYM_REF2(simple_spec_init_c, simple_specification, constant)

   314

   315

/*  subrange_type_name ':' subrange_spec_init */

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SYM_REF2(subrange_type_declaration_c, subrange_type_name, subrange_spec_init)

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   318

/* subrange_specification ASSIGN signed_integer */

   319

SYM_REF2(subrange_spec_init_c, subrange_specification, signed_integer)

   320

   321

/*  integer_type_name '(' subrange')' */

   322

SYM_REF2(subrange_specification_c, integer_type_name, subrange)

   323

   324

/*  signed_integer DOTDOT signed_integer */

   325

SYM_REF2(subrange_c, lower_limit, upper_limit)

   326

   327

/*  enumerated_type_name ':' enumerated_spec_init */

   328

SYM_REF2(enumerated_type_declaration_c, enumerated_type_name, enumerated_spec_init)

   329

   330

/* enumerated_specification ASSIGN enumerated_value */

   331

SYM_REF2(enumerated_spec_init_c, enumerated_specification, enumerated_value)

   332

   333

/* helper symbol for enumerated_specification->enumerated_spec_init */

   334

/* enumerated_value_list ',' enumerated_value */

   335

SYM_LIST(enumerated_value_list_c)

   336

   337

/* enumerated_type_name '#' identifier */

   338

SYM_REF2(enumerated_value_c, type, value)

   339

   340

/*  identifier ':' array_spec_init */

   341

SYM_REF2(array_type_declaration_c, identifier, array_spec_init)

   342

   343

/* array_specification [ASSIGN array_initialization} */

   344

/* array_initialization may be NULL ! */

   345

SYM_REF2(array_spec_init_c, array_specification, array_initialization)

   346

   347

/* ARRAY '[' array_subrange_list ']' OF non_generic_type_name */

   348

SYM_REF2(array_specification_c, array_subrange_list, non_generic_type_name)

   349

   350

/* helper symbol for array_specification */

   351

/* array_subrange_list ',' subrange */

   352

SYM_LIST(array_subrange_list_c)

   353

   354

/* array_initialization:  '[' array_initial_elements_list ']' */

   355

/* helper symbol for array_initialization */

   356

/* array_initial_elements_list ',' array_initial_elements */

   357

SYM_LIST(array_initial_elements_list_c)

   358

   359

/* integer '(' [array_initial_element] ')' */

   360

/* array_initial_element may be NULL ! */

   361

SYM_REF2(array_initial_elements_c, integer, array_initial_element)

   362

   363

/*  structure_type_name ':' structure_specification */

   364

SYM_REF2(structure_type_declaration_c, structure_type_name, structure_specification)

   365

   366

/* structure_type_name ASSIGN structure_initialization */

   367

/* structure_initialization may be NULL ! */

   368

SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)

   369

   370

/* helper symbol for structure_declaration */

   371

/* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */

   372

/* structure_element_declaration_list structure_element_declaration ';' */

   373

SYM_LIST(structure_element_declaration_list_c)

   374

   375

/*  structure_element_name ':' *_spec_init */

   376

SYM_REF2(structure_element_declaration_c, structure_element_name, spec_init)

   377

   378

/* helper symbol for structure_initialization */

   379

/* structure_initialization: '(' structure_element_initialization_list ')' */

   380

/* structure_element_initialization_list ',' structure_element_initialization */

   381

SYM_LIST(structure_element_initialization_list_c)

   382

   383

/*  structure_element_name ASSIGN value */

   384

SYM_REF2(structure_element_initialization_c, structure_element_name, value)

   385

   386

/*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */

   387

/*

   388

 * NOTE:

   389

 * (Summary: Contrary to what is expected, the

   390

 *           string_type_declaration_c is not used to store

   391

 *           simple string type declarations that do not include

   392

 *           size limits.

   393

 *           For e.g.:

   394

 *             str1_type: STRING := "hello!"

   395

 *           will be stored in a simple_type_declaration_c

   396

 *           instead of a string_type_declaration_c.

   397

 *           The following:

   398

 *             str2_type: STRING [64] := "hello!"

   399

 *           will be stored in a sring_type_declaration_c

   400

 *

   401

 *           Read on for why this is done...

   402

 * End Summary)

   403

 *

   404

 * According to the spec, the valid construct

   405

 * TYPE new_str_type : STRING := "hello!"; END_TYPE

   406

 * has two possible routes to type_declaration...

   407

 *

   408

 * Route 1:

   409

 * type_declaration: single_element_type_declaration

   410

 * single_element_type_declaration: simple_type_declaration

   411

 * simple_type_declaration: identifier ':' simple_spec_init

   412

 * simple_spec_init: simple_specification ASSIGN constant

   413

 * (shift:  identifier <- 'new_str_type')

   414

 * simple_specification: elementary_type_name

   415

 * elementary_type_name: STRING

   416

 * (shift: elementary_type_name <- STRING)

   417

 * (reduce: simple_specification <- elementary_type_name)

   418

 * (shift: constant <- "hello!")

   419

 * (reduce: simple_spec_init: simple_specification ASSIGN constant)

   420

 * (reduce: ...)

   421

 *

   422

 *

   423

 * Route 2:

   424

 * type_declaration: string_type_declaration

   425

 * string_type_declaration: identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init

   426

 * (shift:  identifier <- 'new_str_type')

   427

 * elementary_string_type_name: STRING

   428

 * (shift: elementary_string_type_name <- STRING)

   429

 * (shift: string_type_declaration_size <-  empty )

   430

 * string_type_declaration_init: ASSIGN character_string

   431

 * (shift: character_string <- "hello!")

   432

 * (reduce: string_type_declaration_init <- ASSIGN character_string)

   433

 * (reduce: string_type_declaration <- identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init )

   434

 * (reduce: type_declaration <- string_type_declaration)

   435

 *

   436

 *

   437

 * At first glance it seems that removing route 1 would make

   438

 * the most sense. Unfortunately the construct 'simple_spec_init'

   439

 * shows up multiple times in other rules, so changing this construct

   440

 * would also mean changing all the rules in which it appears.

   441

 * I (Mario) therefore chose to remove route 2 instead. This means

   442

 * that the above declaration gets stored in a

   443

 * simple_type_declaration_c, and not in a string_type_declaration_c

   444

 * as would be expected!

   445

 */

   446

/*  string_type_name ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init */

   447

SYM_REF4(string_type_declaration_c,	string_type_name,

   448

					elementary_string_type_name,

   449

					string_type_declaration_size,

   450

					string_type_declaration_init) /* may be == NULL! */

   451

   452

   453

/*********************/

   454

/* B 1.4 - Variables */

   455

/*********************/

   456

SYM_REF1(symbolic_variable_c, var_name)

   457

   458

/********************************************/

   459

/* B.1.4.1   Directly Represented Variables */

   460

/********************************************/

   461

SYM_TOKEN(direct_variable_c)

   462

   463

/*************************************/

   464

/* B.1.4.2   Multi-element Variables */

   465

/*************************************/

   466

/*  subscripted_variable '[' subscript_list ']' */

   467

SYM_REF2(array_variable_c, subscripted_variable, subscript_list)

   468

   469

/* subscript_list ',' subscript */

   470

SYM_LIST(subscript_list_c)

   471

   472

/*  record_variable '.' field_selector */

   473

/*  WARNING: input and/or output variables of function blocks

   474

 *           may be accessed as fields of a structured variable!

   475

 *           Code handling a structured_variable_c must take

   476

 *           this into account!

   477

 */

   478

SYM_REF2(structured_variable_c, record_variable, field_selector)

   479

   480

/******************************************/

   481

/* B 1.4.3 - Declaration & Initialisation */

   482

/******************************************/

   483

SYM_REF0(constant_option_c)

   484

SYM_REF0(retain_option_c)

   485

SYM_REF0(non_retain_option_c)

   486

   487

/* option -> the RETAIN/NON_RETAIN/<NULL> directive... */

   488

/* NOTE: We need to implicitly define the EN and ENO function and FB parameters when the user

   489

 *       does not do it explicitly in the IEC 61131-3 source code. 

   490

 *       To be able to distinguish later on between implictly and explicitly defined

   491

 *       variables, we use the 'method' flag that allows us to remember

   492

 *       whether this declaration was in the original source code (method -> implicit_definition_c) 

   493

 *       or not (method -> explicit_definition_c).

   494

 */

   495

SYM_REF3(input_declarations_c, option, input_declaration_list, method)

   496

   497

/* helper symbol for input_declarations */

   498

SYM_LIST(input_declaration_list_c)

   499

   500

/* NOTE: The formal definition of the standard is erroneous, as it simply does not

   501

 *       consider the EN and ENO keywords!

   502

 *       The semantic description of the languages clearly states that these may be

   503

 *       used in several ways. One of them is to declare an EN input parameter, or

   504

 *       an ENO output parameter.

   505

 *       We have added the 'en_param_declaration_c' and 'eno_param_declaration_c' 

   506

 *       to cover for this.

   507

 *

   508

 *       We could have re-used the standard class used for all other input variables (with

   509

 *       an identifier set to 'EN' or 'ENO') however we may sometimes need to add this

   510

 *       declaration implicitly (if the user does not include it in the source

   511

 *       code himself), and it is good to know whether it was added implicitly or not.

   512

 *       So we create a new class that has a 'method' flag that allows us to remember

   513

 *       whether this declaration was in the original source code (method -> implicit_definition_c) 

   514

 *       or not (method -> explicit_definition_c).