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postgresql/src/backend/parser
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Tom Lane e56bce5d43 Reconsider the handling of procedure OUT parameters. 
Commit 2453ea142 redefined pg_proc.proargtypes to include the types of
OUT parameters, for procedures only.  While that had some advantages
for implementing the SQL-spec behavior of DROP PROCEDURE, it was pretty
disastrous from a number of other perspectives.  Notably, since the
primary key of pg_proc is name + proargtypes, this made it possible to
have multiple procedures with identical names + input arguments and
differing output argument types.  That would make it impossible to call
any one of the procedures by writing just NULL (or "?", or any other
data-type-free notation) for the output argument(s).  The change also
seems likely to cause grave confusion for client applications that
examine pg_proc and expect the traditional definition of proargtypes.

Hence, revert the definition of proargtypes to what it was, and
undo a number of complications that had been added to support that.

To support the SQL-spec behavior of DROP PROCEDURE, when there are
no argmode markers in the command's parameter list, we perform the
lookup both ways (that is, matching against both proargtypes and
proallargtypes), succeeding if we get just one unique match.
In principle this could result in ambiguous-function failures
that would not happen when using only one of the two rules.
However, overloading of procedure names is thought to be a pretty
rare usage, so this shouldn't cause many problems in practice.
Postgres-specific code such as pg_dump can defend against any
possibility of such failures by being careful to specify argmodes
for all procedure arguments.

This also fixes a few other bugs in the area of CALL statements
with named parameters, and improves the documentation a little.

catversion bump forced because the representation of procedures
with OUT arguments changes.

Discussion: https://postgr.es/m/3742981.1621533210@sss.pgh.pa.us
 		2021-06-10 17:11:36 -04:00
..
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:04 +02:00
Makefile Split all OBJS style lines in makefiles into one-line-per-entry style. 2019-11-05 14:41:07 -08:00
README Move keywords.c/kwlookup.c into src/common/. 2016-03-23 20:22:08 -04:00
analyze.c Reconsider the handling of procedure OUT parameters. 2021-06-10 17:11:36 -04:00
check_keywords.pl Update copyright for 2021 2021-01-02 13:06:25 -05:00
gram.y Reconsider the handling of procedure OUT parameters. 2021-06-10 17:11:36 -04:00
parse_agg.c Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
parse_clause.c Fix inconsistent equalfuncs.c behavior for FuncCall.funcformat. 2021-06-06 15:46:58 -04:00
parse_coerce.c Refactor some error messages for easier translation 2021-05-12 07:42:51 +02:00
parse_collate.c Update copyright for 2021 2021-01-02 13:06:25 -05:00
parse_cte.c Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
parse_enr.c Update copyright for 2021 2021-01-02 13:06:25 -05:00
parse_expr.c Allow an alias to be attached to a JOIN ... USING 2021-03-31 17:10:50 +02:00
parse_func.c Reconsider the handling of procedure OUT parameters. 2021-06-10 17:11:36 -04:00
parse_node.c Update copyright for 2021 2021-01-02 13:06:25 -05:00
parse_oper.c Reconsider the handling of procedure OUT parameters. 2021-06-10 17:11:36 -04:00
parse_param.c Update copyright for 2021 2021-01-02 13:06:25 -05:00
parse_relation.c Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
parse_target.c Remove no-longer-used RTE argument of markVarForSelectPriv(). 2021-02-11 11:23:25 -05:00
parse_type.c Add the ability for the core grammar to have more than one parse target. 2021-01-04 11:03:22 -05:00
parse_utilcmd.c Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
parser.c Re-implement pl/pgsql's expression and assignment parsing. 2021-01-04 11:52:00 -05:00
scan.l Update copyright for 2021 2021-01-02 13:06:25 -05:00
scansup.c Update copyright for 2021 2021-01-02 13:06:25 -05:00

README 

src/backend/parser/README

Parser
======

This directory does more than tokenize and parse SQL queries.  It also
creates Query structures for the various complex queries that are passed
to the optimizer and then executor.

parser.c	things start here
scan.l		break query into tokens
scansup.c	handle escapes in input strings
gram.y		parse the tokens and produce a "raw" parse tree
analyze.c	top level of parse analysis for optimizable queries
parse_agg.c	handle aggregates, like SUM(col1),  AVG(col2), ...
parse_clause.c	handle clauses like WHERE, ORDER BY, GROUP BY, ...
parse_coerce.c	handle coercing expressions to different data types
parse_collate.c	assign collation information in completed expressions
parse_cte.c	handle Common Table Expressions (WITH clauses)
parse_expr.c	handle expressions like col, col + 3, x = 3 or x = 4
parse_func.c	handle functions, table.column and column identifiers
parse_node.c	create nodes for various structures
parse_oper.c	handle operators in expressions
parse_param.c	handle Params (for the cases used in the core backend)
parse_relation.c support routines for tables and column handling
parse_target.c	handle the result list of the query
parse_type.c	support routines for data type handling
parse_utilcmd.c	parse analysis for utility commands (done at execution time)

See also src/common/keywords.c, which contains the table of standard
keywords and the keyword lookup function.  We separated that out because
various frontend code wants to use it too.