mirror of
https://github.com/postgres/postgres.git
synced 2026-02-27 03:40:28 -05:00
40c24bfef9
The SQL spec calls out nonstandard syntax for certain function calls, for example substring() with numeric position info is supposed to be spelled "SUBSTRING(string FROM start FOR count)". We accept many of these things, but up to now would not print them in the same format, instead simplifying down to "substring"(string, start, count). That's long annoyed me because it creates an interoperability problem: we're gratuitously injecting Postgres-specific syntax into what might otherwise be a perfectly spec-compliant view definition. However, the real reason for addressing it right now is to support a planned change in the semantics of EXTRACT() a/k/a date_part(). When we switch that to returning numeric, we'll have the parser translate EXTRACT() to some new function name (might as well be "extract" if you ask me) and then teach ruleutils.c to reverse-list that per SQL spec. In this way existing calls to date_part() will continue to have the old semantics. To implement this, invent a new CoercionForm value COERCE_SQL_SYNTAX, and make the parser insert that rather than COERCE_EXPLICIT_CALL when the input has SQL-spec decoration. (But if the input has the form of a plain function call, continue to mark it COERCE_EXPLICIT_CALL, even if it's calling one of these functions.) Then ruleutils.c recognizes COERCE_SQL_SYNTAX as a cue to emit SQL call syntax. It can know which decoration to emit using hard-wired knowledge about the functions that could be called this way. (While this solution isn't extensible without manual additions, neither is the grammar, so this doesn't seem unmaintainable.) Notice that this solution will reverse-list a function call with SQL decoration only if it was entered that way; so dump-and-reload will not by itself produce any changes in the appearance of views. This requires adding a CoercionForm field to struct FuncCall. (I couldn't resist the temptation to rearrange that struct's field order a tad while I was at it.) FuncCall doesn't appear in stored rules, so that change isn't a reason for a catversion bump, but I did one anyway because the new enum value for CoercionForm fields could confuse old backend code. Possible future work: * Perhaps CoercionForm should now be renamed to DisplayForm, or something like that, to reflect its more general meaning. This'd require touching a couple hundred places, so it's not clear it's worth the code churn. * The SQLValueFunction node type, which was invented partly for the same goal of improving SQL-compatibility of view output, could perhaps be replaced with regular function calls marked with COERCE_SQL_SYNTAX. It's unclear if this would be a net code savings, however. Discussion: https://postgr.es/m/42b73d2d-da12-ba9f-570a-420e0cce19d9@phystech.edu
109 lines
3.4 KiB
C
109 lines
3.4 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* makefuncs.h
|
|
* prototypes for the creator functions of various nodes
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* src/include/nodes/makefuncs.h
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#ifndef MAKEFUNC_H
|
|
#define MAKEFUNC_H
|
|
|
|
#include "nodes/execnodes.h"
|
|
#include "nodes/parsenodes.h"
|
|
|
|
|
|
extern A_Expr *makeA_Expr(A_Expr_Kind kind, List *name,
|
|
Node *lexpr, Node *rexpr, int location);
|
|
|
|
extern A_Expr *makeSimpleA_Expr(A_Expr_Kind kind, char *name,
|
|
Node *lexpr, Node *rexpr, int location);
|
|
|
|
extern Var *makeVar(Index varno,
|
|
AttrNumber varattno,
|
|
Oid vartype,
|
|
int32 vartypmod,
|
|
Oid varcollid,
|
|
Index varlevelsup);
|
|
|
|
extern Var *makeVarFromTargetEntry(Index varno,
|
|
TargetEntry *tle);
|
|
|
|
extern Var *makeWholeRowVar(RangeTblEntry *rte,
|
|
Index varno,
|
|
Index varlevelsup,
|
|
bool allowScalar);
|
|
|
|
extern TargetEntry *makeTargetEntry(Expr *expr,
|
|
AttrNumber resno,
|
|
char *resname,
|
|
bool resjunk);
|
|
|
|
extern TargetEntry *flatCopyTargetEntry(TargetEntry *src_tle);
|
|
|
|
extern FromExpr *makeFromExpr(List *fromlist, Node *quals);
|
|
|
|
extern Const *makeConst(Oid consttype,
|
|
int32 consttypmod,
|
|
Oid constcollid,
|
|
int constlen,
|
|
Datum constvalue,
|
|
bool constisnull,
|
|
bool constbyval);
|
|
|
|
extern Const *makeNullConst(Oid consttype, int32 consttypmod, Oid constcollid);
|
|
|
|
extern Node *makeBoolConst(bool value, bool isnull);
|
|
|
|
extern Expr *makeBoolExpr(BoolExprType boolop, List *args, int location);
|
|
|
|
extern Alias *makeAlias(const char *aliasname, List *colnames);
|
|
|
|
extern RelabelType *makeRelabelType(Expr *arg, Oid rtype, int32 rtypmod,
|
|
Oid rcollid, CoercionForm rformat);
|
|
|
|
extern RangeVar *makeRangeVar(char *schemaname, char *relname, int location);
|
|
|
|
extern TypeName *makeTypeName(char *typnam);
|
|
extern TypeName *makeTypeNameFromNameList(List *names);
|
|
extern TypeName *makeTypeNameFromOid(Oid typeOid, int32 typmod);
|
|
|
|
extern ColumnDef *makeColumnDef(const char *colname,
|
|
Oid typeOid, int32 typmod, Oid collOid);
|
|
|
|
extern FuncExpr *makeFuncExpr(Oid funcid, Oid rettype, List *args,
|
|
Oid funccollid, Oid inputcollid, CoercionForm fformat);
|
|
|
|
extern FuncCall *makeFuncCall(List *name, List *args,
|
|
CoercionForm funcformat, int location);
|
|
|
|
extern Expr *make_opclause(Oid opno, Oid opresulttype, bool opretset,
|
|
Expr *leftop, Expr *rightop,
|
|
Oid opcollid, Oid inputcollid);
|
|
|
|
extern Expr *make_andclause(List *andclauses);
|
|
extern Expr *make_orclause(List *orclauses);
|
|
extern Expr *make_notclause(Expr *notclause);
|
|
|
|
extern Node *make_and_qual(Node *qual1, Node *qual2);
|
|
extern Expr *make_ands_explicit(List *andclauses);
|
|
extern List *make_ands_implicit(Expr *clause);
|
|
|
|
extern IndexInfo *makeIndexInfo(int numattrs, int numkeyattrs, Oid amoid,
|
|
List *expressions, List *predicates,
|
|
bool unique, bool isready, bool concurrent);
|
|
|
|
extern DefElem *makeDefElem(char *name, Node *arg, int location);
|
|
extern DefElem *makeDefElemExtended(char *nameSpace, char *name, Node *arg,
|
|
DefElemAction defaction, int location);
|
|
|
|
extern GroupingSet *makeGroupingSet(GroupingSetKind kind, List *content, int location);
|
|
|
|
extern VacuumRelation *makeVacuumRelation(RangeVar *relation, Oid oid, List *va_cols);
|
|
|
|
#endif /* MAKEFUNC_H */
|