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Before, SQL-level boolean constants were represented by a string with a cast, and internal Boolean values in DDL commands were usually represented by Integer nodes. This takes the place of both of these uses, making the intent clearer and having some amount of type safety. Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/8c1a2e37-c68d-703c-5a83-7a6077f4f997@enterprisedb.com
80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* value.h
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* interface for value nodes
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*
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*
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* Copyright (c) 2003-2022, PostgreSQL Global Development Group
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*
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* src/include/nodes/value.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef VALUE_H
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#define VALUE_H
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#include "nodes/nodes.h"
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/*
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* The node types Integer, Float, String, and BitString are used to represent
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* literals in the lexer and are also used to pass constants around in the
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* parser. One difference between these node types and, say, a plain int or
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* char * is that the nodes can be put into a List.
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*
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* (There used to be a Value node, which encompassed all these different node types. Hence the name of this file.)
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*/
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typedef struct Integer
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{
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NodeTag type;
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int ival;
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} Integer;
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/*
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* Float is internally represented as string. Using T_Float as the node type
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* simply indicates that the contents of the string look like a valid numeric
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* literal. The value might end up being converted to NUMERIC, so we can't
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* store it internally as a C double, since that could lose precision. Since
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* these nodes are generally only used in the parsing process, not for runtime
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* data, it's better to use the more general representation.
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*
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* Note that an integer-looking string will get lexed as T_Float if the value
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* is too large to fit in an 'int'.
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*/
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typedef struct Float
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{
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NodeTag type;
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char *fval;
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} Float;
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typedef struct Boolean
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{
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NodeTag type;
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bool boolval;
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} Boolean;
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typedef struct String
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{
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NodeTag type;
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char *sval;
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} String;
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typedef struct BitString
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{
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NodeTag type;
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char *bsval;
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} BitString;
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#define intVal(v) (castNode(Integer, v)->ival)
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#define floatVal(v) atof(castNode(Float, v)->fval)
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#define boolVal(v) (castNode(Boolean, v)->boolval)
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#define strVal(v) (castNode(String, v)->sval)
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extern Integer *makeInteger(int i);
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extern Float *makeFloat(char *numericStr);
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extern Boolean *makeBoolean(bool var);
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extern String *makeString(char *str);
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extern BitString *makeBitString(char *str);
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#endif /* VALUE_H */
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