1/*-------------------------------------------------------------------------
2 *
3 * value.h
4 * interface for Value nodes
5 *
6 *
7 * Copyright (c) 2003-2019, PostgreSQL Global Development Group
8 *
9 * src/include/nodes/value.h
10 *
11 *-------------------------------------------------------------------------
12 */
13
14#ifndef VALUE_H
15#define VALUE_H
16
17#include "nodes/nodes.h"
18
19/*----------------------
20 * Value node
21 *
22 * The same Value struct is used for five node types: T_Integer,
23 * T_Float, T_String, T_BitString, T_Null.
24 *
25 * Integral values are actually represented by a machine integer,
26 * but both floats and strings are represented as strings.
27 * Using T_Float as the node type simply indicates that
28 * the contents of the string look like a valid numeric literal.
29 *
30 * (Before Postgres 7.0, we used a double to represent T_Float,
31 * but that creates loss-of-precision problems when the value is
32 * ultimately destined to be converted to NUMERIC. Since Value nodes
33 * are only used in the parsing process, not for runtime data, it's
34 * better to use the more general representation.)
35 *
36 * Note that an integer-looking string will get lexed as T_Float if
37 * the value is too large to fit in an 'int'.
38 *
39 * Nulls, of course, don't need the value part at all.
40 *----------------------
41 */
42typedef struct Value
43{
44 NodeTag type; /* tag appropriately (eg. T_String) */
45 union ValUnion
46 {
47 int ival; /* machine integer */
48 char *str; /* string */
49 } val;
50} Value;
51
52#define intVal(v) (((Value *)(v))->val.ival)
53#define floatVal(v) atof(((Value *)(v))->val.str)
54#define strVal(v) (((Value *)(v))->val.str)
55
56extern Value *makeInteger(int i);
57extern Value *makeFloat(char *numericStr);
58extern Value *makeString(char *str);
59extern Value *makeBitString(char *str);
60
61#endif /* VALUE_H */
62