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c9d5298485
Invent new RawParseModes that allow the core grammar to handle pl/pgsql expressions and assignments directly, and thereby get rid of a lot of hackery in pl/pgsql's parser. This moves a good deal of knowledge about pl/pgsql into the core code: notably, we have to invent a CoercionContext that matches pl/pgsql's (rather dubious) historical behavior for assignment coercions. That's getting away from the original idea of pl/pgsql as an arm's-length extension of the core, but really we crossed that bridge a long time ago. The main advantage of doing this is that we can now use the core parser to generate FieldStore and/or SubscriptingRef nodes to handle assignments to pl/pgsql variables that are records or arrays. That fixes a number of cases that had never been implemented in pl/pgsql assignment, such as nested records and array slicing, and it allows pl/pgsql assignment to support the datatype-specific subscripting behaviors introduced in commit c7aba7c14. There are cosmetic benefits too: when a syntax error occurs in a pl/pgsql expression, the error report no longer includes the confusing "SELECT" keyword that used to get prefixed to the expression text. Also, there seem to be some small speed gains. Discussion: https://postgr.es/m/4165684.1607707277@sss.pgh.pa.us
69 lines
2.0 KiB
C
69 lines
2.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* parser.h
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* Definitions for the "raw" parser (flex and bison phases only)
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*
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* This is the external API for the raw lexing/parsing functions.
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*
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/parser/parser.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PARSER_H
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#define PARSER_H
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#include "nodes/parsenodes.h"
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/*
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* RawParseMode determines the form of the string that raw_parser() accepts:
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*
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* RAW_PARSE_DEFAULT: parse a semicolon-separated list of SQL commands,
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* and return a List of RawStmt nodes.
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*
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* RAW_PARSE_TYPE_NAME: parse a type name, and return a one-element List
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* containing a TypeName node.
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*
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* RAW_PARSE_PLPGSQL_EXPR: parse a PL/pgSQL expression, and return
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* a one-element List containing a RawStmt node.
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*
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* RAW_PARSE_PLPGSQL_ASSIGNn: parse a PL/pgSQL assignment statement,
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* and return a one-element List containing a RawStmt node. "n"
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* gives the number of dotted names comprising the target ColumnRef.
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*/
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typedef enum
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{
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RAW_PARSE_DEFAULT = 0,
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RAW_PARSE_TYPE_NAME,
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RAW_PARSE_PLPGSQL_EXPR,
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RAW_PARSE_PLPGSQL_ASSIGN1,
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RAW_PARSE_PLPGSQL_ASSIGN2,
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RAW_PARSE_PLPGSQL_ASSIGN3
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} RawParseMode;
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/* Values for the backslash_quote GUC */
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typedef enum
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{
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BACKSLASH_QUOTE_OFF,
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BACKSLASH_QUOTE_ON,
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BACKSLASH_QUOTE_SAFE_ENCODING
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} BackslashQuoteType;
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/* GUC variables in scan.l (every one of these is a bad idea :-() */
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extern int backslash_quote;
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extern bool escape_string_warning;
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extern PGDLLIMPORT bool standard_conforming_strings;
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/* Primary entry point for the raw parsing functions */
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extern List *raw_parser(const char *str, RawParseMode mode);
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/* Utility functions exported by gram.y (perhaps these should be elsewhere) */
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extern List *SystemFuncName(char *name);
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extern TypeName *SystemTypeName(char *name);
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#endif /* PARSER_H */
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