matiec: comparison stage1_2/iec

equal deleted inserted replaced

-:5681f600ac18
+:1cc0e1ca2aad
 /*********************/
 /* B 1.2 - Constants */
 /*********************/
 %type <leaf>	constant
-%type <leaf>	non_negative_constant
+%type <leaf>	non_int_or_real_constant
 /******************************/
 /* B 1.2.1 - Numeric Literals */
 /******************************/
 /* Done totally within flex...
 // %type  <leaf>	multiply_operator
 %type  <leaf>	power_expression
 %type  <leaf>	unary_expression
 // %type  <leaf>	unary_operator
 %type  <leaf>	primary_expression
-%type  <leaf>	non_negative_primary_expression
+%type  <leaf>	non_int_or_real_primary_expression
 /* intermediate helper symbol for primary_expression */
 %type  <leaf>	function_invocation
 // %token AND
 // %token XOR
 /*********************/
 /* B 1.2 - Constants */
 /*********************/
 constant:
-numeric_literal
+character_string
-| character_string
 | time_literal
 | bit_string_literal
 | boolean_literal
+| numeric_literal
+/* NOTE: Our definition of numeric_literal is diferent than the one in the standard.
+*       We will now add what is missing in our definition of numeric literal, so our
+*       definition of constant matches what the definition of constant in the standard.
+*/
 /* NOTE: in order to remove reduce/reduce conflicts,
 * [between -9.5 being parsed as
 *     (i)   a signed real,
 *     (ii)  or as a real preceded by the '-' operator
 *  ]
 *  we need to define a variant of the constant construct
-*  where any constant is never preceded by the '-' character.
+*  where any real or integer constant is always preceded by
-* In order to do this, we have borugh the signed_real
+*  a sign (i.e. the '-' or '+' characters).
-* directly into the definition of the constant construct
+*  (For more info, see comment in the construct non_int_or_real_primary_expression)
-* (so we can define another non_negative_constant
+*
-* construct that does not include it!)
+* For the above reason, our definition of the numeric_literal construct
-*/
+* is missing the integer and real constrcuts (when not preceded by a sign)
-| signed_real
+* so we add then here explicitly!
-/* NOTE: in order to remove reduce/reduce conflicts,
+*/
-* unsigned_integer, signed_integer, binary_integer, octal_integer
+| real
-* and hex_integer have been integrated directly into
+| integer
-* the constants construct, instead of belonging to
-* both the bit_string_literal or integer_literal
-* construct.
-*/
 /* NOTE: unsigned_integer, although used in some
 * rules, is not defined in the spec!
 * We therefore replaced unsigned_integer as integer
 */
-/*| integer {} */  /* i.e. an unsigned_integer */ /* NOTE: already included as a signed integer! */
+;
-| signed_integer
-| binary_integer
-| octal_integer
-| hex_integer
-;
+non_int_or_real_constant:
+character_string
+| time_literal
+| bit_string_literal
+| boolean_literal
+| numeric_literal
+/* NOTE: Our definition of numeric_literal is diferent than the one in the standard.
+*       It is missing the integer and real when not prefixed by a sign
+*       (i.e. -54, +42 is included in numerical_literal,
+*        but   54,  42 is not parsed as a numeric_literal!!)
+*/
 /* NOTE: in order to remove reduce/reduce conflicts,
 * [between -9.5 being parsed as
 *     (i)   a signed real,
 *     (ii)  or as a real preceded by the '-' operator
 *  ]
+* [and a similar situation for integers!]
 *  we need to define a variant of the constant construct
-*  where any constant is never preceded by the '-' character.
+*  where any real or integer constant is always preceded by
-* In order to do this, we have borugh the signed_real
+*  a sign (i.e. the '-' or '+' characters).
-* directly into the definition of the constant construct
+*
-* (so we can define another non_negative_constant
+* For the above reason, our definition of the numeric_literal construct
-* construct that does not include it!)
+* is missing the integer and real constrcuts (when not preceded by a sign)
 */
-non_negative_constant:
-numeric_literal
-| character_string
-| time_literal
-| bit_string_literal
-| boolean_literal
-/* NOTE: in order to remove reduce/reduce conflicts,
-* [between -9.5 being parsed as
-*     (i)   a signed real,
-*     (ii)  or as a real preceded by the '-' operator
-*  ]
-*  we need to define a variant of the constant construct
-*  where any constant is never preceded by the '-' character.
-* In order to do this, we have borugh the signed_real
-* directly into the definition of the constant construct
-* (so we can define another non_negative_constant
-* construct that does not include it!)
-*/
-/* | signed_real */
-| real /* an unsigned real */
-/* NOTE: in order to remove reduce/reduce conflicts,
-* unsigned_integer, signed_integer, binary_integer, octal_integer
-* and hex_integer have been integrated directly into
-* the constants construct, instead of belonging to
-* both the bit_string_literal or integer_literal
-* construct.
-*/
-/* NOTE: unsigned_integer, although used in some
-* rules, is not defined in the spec!
-* We therefore replaced unsigned_integer as integer
-*/
-| integer  /* i.e. an unsigned_integer */
-/* | signed_integer */
-| binary_integer
-| octal_integer
-| hex_integer
 ;
 /******************************/
 /* B 1.2.1 - Numeric Literals */
 	{$$ = new integer_literal_c($1, $3, locloc(@$));}
 | integer_type_name '#' octal_integer
 	{$$ = new integer_literal_c($1, $3, locloc(@$));}
 | integer_type_name '#' hex_integer
 	{$$ = new integer_literal_c($1, $3, locloc(@$));}
-/* NOTE: see note in the definition of constant for reason
+| binary_integer
-* why signed_integer, binary_integer, octal_integer
+| octal_integer
-* and hex_integer are missing here!
+| hex_integer
-*/
+//|signed_integer  /* We expand the construct signed_integer here, so we can remove one of its constituents */
+//|  integer       /* REMOVED! see note in the definition of constant for reason why integer is missing here! */
+| '+' integer   {$$ = $2;}
+| '-' integer	{$$ = new neg_integer_c($2, locloc(@$));}
 /* ERROR_CHECK_BEGIN */
 | integer_type_name signed_integer
 	{$$ = NULL; print_err_msg(locl(@1), locf(@2), "'#' missing between integer type name and value in integer literal."); yynerrs++;}
 | integer_type_name binary_integer
 	{$$ = NULL; print_err_msg(locl(@1), locf(@2), "'#' missing between integer type name and value in integer literal."); yynerrs++;}
 	 yyerrok;
 	}
 /* ERROR_CHECK_END */
 ;
+/* NOTE: this construct is used in the definition of integer_literal. However, in order to remove
+*       a reduce/reduce conflict (see NOTE in definition of constant for reason why)
+*       it is not used directly, but rather its expansion is copied there.
+*
+*       If for some reason you need to change the definition of signed_integer, don't forget
+*       to change its expansion in integer_literal too!
+*/
 signed_integer:
 integer
 | '+' integer   {$$ = $2;}
 | '-' integer	{$$ = new neg_integer_c($2, locloc(@$));}
 ;
 real_literal:
-/* NOTE: see note in the definition of constant for reason
+// signed_real /* We expand the construct signed_integer here, so we can remove one of its constituents */
-* why signed_real is missing here!
+// real        /* REMOVED! see note in the definition of constant for reason why real is missing here! */
-*/
+'+' real	{$$ = $2;}
-/*  signed_real */
+| '-' real	{$$ = new neg_real_c($2, locloc(@2));}
-real_type_name '#' signed_real
+| real_type_name '#' signed_real
 	{$$ = new real_literal_c($1, $3, locloc(@$));}
 /* ERROR_CHECK_BEGIN */
 | real_type_name signed_real
 	{$$ = NULL; print_err_msg(locl(@1), locf(@2), "'#' missing between real type name and value in real literal."); yynerrs++;}
 | real_type_name '#' error
 	 yyerrok;
 	}
 /* ERROR_CHECK_END */
 ;
+/* NOTE: this construct is used in the definition of real_literal. However, in order to remove
+*       a reduce/reduce conflict (see NOTE in definition of constant for reason why)
+*       it is not used directly, but rather its expansion is copied there.
+*
+*       If for some reason you need to change the definition of signed_real, don't forget
+*       to change its expansion in real_literal too!
+*/
 signed_real:
 real
 | '+' real	{$$ = $2;}
 | '-' real	{$$ = new neg_real_c($2, locloc(@2));}
 ;
 bit_string_literal:
 bit_string_type_name '#' integer  /* i.e. unsigned_integer */
 	{$$ = new bit_string_literal_c($1, $3, locloc(@$));}
 /* ERROR_CHECK_END */
 ;
 unary_expression:
-non_negative_primary_expression
+primary_expression
-| '-' non_negative_primary_expression
+| '-' non_int_or_real_primary_expression
 	{$$ = new neg_expression_c($2, locloc(@$));}
 | NOT primary_expression
 	{$$ = new not_expression_c($2, locloc(@$));}
 /* ERROR_CHECK_BEGIN */
 | '-' error
 *       OR
 *       expression<-unary_expression<-constant<-integer
 *       (i.e. the constant 9, preceded by a unary negation)
 *
 *       To remove the conflict, we only allow constants without
-*       a preceding '-' to be used in primary_expression
+*       integer or reals that are not preceded by a sign
+*       (i.e. a '-' or '+' character) to be used in primary_expression
 *       (i.e. as a parameter to the unary negation operator)
+*
+*       e.g.  '-42', '+54', '42', '54' are all allowed in primary expression
+*       according to the standard. However, we will allow only '-42' and '+54'
+*       to be used as an argument to the negation operator ('-').
+*/
+/* NOTE: Notice that the standard considers the following syntax correct:
+*         VAR intv: INT; END_VAR
+*         intv :=      42;         <----- OK
+*         intv :=     -42;         <----- OK
+*         intv :=     +42;         <----- OK
+*         intv :=    --42;         <----- OK!!
+*         intv :=    -+42;         <----- OK!!
+*         intv :=  -(--42);        <----- OK!!
+*         intv :=  -(-+42);        <----- OK!!
+*         intv :=-(-(--42));       <----- OK!!
+*         intv :=-(-(-+42));       <----- OK!!
+*     but does NOT allow the following syntax:
+*         VAR intv: INT; END_VAR
+*         intv :=   ---42;       <----- ERROR!!
+*         intv :=   --+42;       <----- ERROR!!
+*         intv :=  ----42;       <----- ERROR!!
+*         intv :=  ---+42;       <----- ERROR!!
+*
+*    Although strange, we follow the standard to the letter, and do exactly
+*    as stated above!!
 */
 /* NOTE: We use enumerated_value_without_identifier instead of enumerated_value
 *       in order to remove a reduce/reduce conflict between reducing an
 *       identifier to a variable or an enumerated_value.
 *
 *       imply (by introducing syntax that allows to unambiguosly reference an
 *       enumerated value - enum_type#enum_value) that in case the same identifier is used
 *       for a variable and an enumerated value, then the variable shall be
 *       considered.
 */
-non_negative_primary_expression:
+non_int_or_real_primary_expression:
-non_negative_constant
+non_int_or_real_constant
 //| enumerated_value_without_identifier
 | enumerated_value
 | variable
 | '(' expression ')'
 	{$$ = $2;}

changeset 643	1cc0e1ca2aad
parent 616	0c7663fdc8d3
child 667	bd1360f29f15