|
70
|
1 |
/*
|
|
|
2 |
* (c) 2003 Mario de Sousa
|
|
|
3 |
*
|
|
|
4 |
* Offered to the public under the terms of the GNU General Public License
|
|
|
5 |
* as published by the Free Software Foundation; either version 2 of the
|
|
|
6 |
* License, or (at your option) any later version.
|
|
|
7 |
*
|
|
|
8 |
* This program is distributed in the hope that it will be useful, but
|
|
|
9 |
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
10 |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
|
|
|
11 |
* Public License for more details.
|
|
|
12 |
*
|
|
|
13 |
* This code is made available on the understanding that it will not be
|
|
|
14 |
* used in safety-critical situations without a full and competent review.
|
|
|
15 |
*/
|
|
|
16 |
|
|
|
17 |
/*
|
|
|
18 |
* An IEC 61131-3 IL and ST compiler.
|
|
|
19 |
*
|
|
|
20 |
* Based on the
|
|
|
21 |
* FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
|
|
|
22 |
*
|
|
|
23 |
*/
|
|
|
24 |
|
|
|
25 |
|
|
|
26 |
/* Decomposes a variable instance name into its constituents,
|
|
|
27 |
* example:
|
|
|
28 |
* window.points[1].coordinate.x
|
|
|
29 |
*
|
|
|
30 |
* will succesfully return
|
|
|
31 |
* - window
|
|
|
32 |
* - points
|
|
|
33 |
* - coordinate
|
|
|
34 |
* - x
|
|
|
35 |
* on succesive calls to decompose_var_instance_name_c::next_part()
|
|
|
36 |
*/
|
|
|
37 |
class decompose_var_instance_name_c: null_visitor_c {
|
|
|
38 |
|
|
|
39 |
private:
|
|
|
40 |
symbol_c *variable_name;
|
|
|
41 |
symbol_c *next_variable_name;
|
|
|
42 |
symbol_c *current_recursive_variable_name;
|
|
|
43 |
symbol_c *previously_returned_variable_name;
|
|
|
44 |
|
|
|
45 |
public:
|
|
|
46 |
decompose_var_instance_name_c(symbol_c *variable_instance_name) {
|
|
|
47 |
variable_name = variable_instance_name;
|
|
|
48 |
next_variable_name = NULL;
|
|
|
49 |
current_recursive_variable_name = NULL;
|
|
|
50 |
previously_returned_variable_name = NULL;
|
|
|
51 |
}
|
|
|
52 |
|
|
|
53 |
public:
|
|
|
54 |
symbol_c *next_part(void) {
|
|
|
55 |
/* We must always start from the top!
|
|
|
56 |
* See note in the structured_variable_c visitor
|
|
|
57 |
* to understand why...
|
|
|
58 |
*/
|
|
|
59 |
symbol_c *res = (symbol_c *)variable_name->accept(*this);
|
|
|
60 |
next_variable_name = current_recursive_variable_name;
|
|
|
61 |
|
|
|
62 |
if (previously_returned_variable_name == res)
|
|
|
63 |
return NULL;
|
|
|
64 |
previously_returned_variable_name = res;
|
|
|
65 |
return res;
|
|
|
66 |
}
|
|
|
67 |
|
|
|
68 |
public:
|
|
|
69 |
/*********************/
|
|
|
70 |
/* B 1.4 - Variables */
|
|
|
71 |
/*********************/
|
|
|
72 |
void *visit(symbolic_variable_c *symbol) {return (void *)(symbol->var_name);}
|
|
|
73 |
|
|
|
74 |
/********************************************/
|
|
|
75 |
/* B.1.4.1 Directly Represented Variables */
|
|
|
76 |
/********************************************/
|
|
|
77 |
void *visit(direct_variable_c *symbol) {return (void *)symbol;}
|
|
|
78 |
|
|
|
79 |
/*************************************/
|
|
|
80 |
/* B.1.4.2 Multi-element Variables */
|
|
|
81 |
/*************************************/
|
|
|
82 |
/* subscripted_variable '[' subscript_list ']' */
|
|
|
83 |
// SYM_REF2(array_variable_c, subscripted_variable, subscript_list)
|
|
|
84 |
void *visit(array_variable_c *symbol) {
|
|
|
85 |
/* NOTE: the subscripted_variable may itself be a structure!,
|
|
|
86 |
* so we must recursevily visit!
|
|
|
87 |
*/
|
|
|
88 |
return symbol->subscripted_variable->accept(*this);
|
|
|
89 |
}
|
|
|
90 |
|
|
|
91 |
/* record_variable '.' field_selector */
|
|
|
92 |
/* WARNING: input and/or output variables of function blocks
|
|
|
93 |
* may be accessed as fields of a tructured variable!
|
|
|
94 |
* Code handling a structured_variable_c must take
|
|
|
95 |
* this into account!
|
|
|
96 |
*/
|
|
|
97 |
//SYM_REF2(structured_variable_c, record_variable, field_selector)
|
|
|
98 |
void *visit(structured_variable_c *symbol) {
|
|
|
99 |
/* NOTE: The following code will not work, as structured_variable_c
|
|
|
100 |
* are grouped on the left, and not on the right!
|
|
|
101 |
*
|
|
|
102 |
* example: window.origin.x
|
|
|
103 |
* will result in
|
|
|
104 |
* s1 = structured_variable_c("window, "origin");
|
|
|
105 |
* s2 = structured_variable_c(s1, "x");
|
|
|
106 |
* AND NOT
|
|
|
107 |
* s1 = structured_variable_c("origin", "x");
|
|
|
108 |
* s2 = structured_variable_c("window", s1);
|
|
|
109 |
*
|
|
|
110 |
* as the following code assumes!!
|
|
|
111 |
*
|
|
|
112 |
current_variable_name = symbol->field_selector;
|
|
|
113 |
return symbol->record_variable->accept(*this);
|
|
|
114 |
*/
|
|
|
115 |
|
|
|
116 |
/* The correct code, is therefore more complex... */
|
|
|
117 |
if (next_variable_name == symbol) {
|
|
|
118 |
/* NOTE: field_selector is always an identifier_c,
|
|
|
119 |
* so we do not have to recursevily visit it again...
|
|
|
120 |
* return (void *)symbol->field_selector->accept(*this); -> NOT REQUIRED!!
|
|
|
121 |
*/
|
|
|
122 |
return (void *)symbol->field_selector;
|
|
|
123 |
}
|
|
|
124 |
|
|
|
125 |
current_recursive_variable_name = symbol;
|
|
|
126 |
return symbol->record_variable->accept(*this);
|
|
|
127 |
}
|
|
|
128 |
};
|
|
|
129 |
|
|
|
130 |
|
|
|
131 |
|
|
|
132 |
|