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Commitaafefb4

Browse files
committed
Clean up grammar a bit
Simplify the grammar specification of substring() and overlay() a bit,simplify and update some comments.Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>Reviewed-by: Vik Fearing <vik@postgresfriends.org>Reviewed-by: Fabien COELHO <coelho@cri.ensmp.fr>Discussion:https://www.postgresql.org/message-id/flat/a15db31c-d0f8-8ce0-9039-578a31758adb%402ndquadrant.com
1 parent68de144 commitaafefb4

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1 file changed

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‎src/backend/parser/gram.y‎

Lines changed: 23 additions & 50 deletions
Original file line numberDiff line numberDiff line change
@@ -452,7 +452,6 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
452452
%type<list>extract_listoverlay_listposition_list
453453
%type<list>substr_listtrim_list
454454
%type<list>opt_intervalinterval_second
455-
%type<node>overlay_placingsubstr_fromsubstr_for
456455
%type<str>unicode_normal_form
457456

458457
%type<boolean>opt_instead
@@ -13797,11 +13796,6 @@ func_expr_common_subexpr:
1379713796
}
1379813797
|OVERLAY'('overlay_list')'
1379913798
{
13800-
/* overlay(A PLACING B FROM C FOR D) is converted to
13801-
* overlay(A, B, C, D)
13802-
* overlay(A PLACING B FROM C) is converted to
13803-
* overlay(A, B, C)
13804-
*/
1380513799
$$ = (Node *) makeFuncCall(SystemFuncName("overlay"),$3,@1);
1380613800
}
1380713801
|POSITION'('position_list')'
@@ -14437,63 +14431,45 @@ unicode_normal_form:
1443714431
|NFKD{$$ ="nfkd"; }
1443814432
;
1443914433

14440-
/* OVERLAY() arguments
14441-
* SQL99 defines the OVERLAY() function:
14442-
* o overlay(text placing text from int for int)
14443-
* o overlay(text placing text from int)
14444-
* and similarly for binary strings
14445-
*/
14434+
/* OVERLAY() arguments*/
1444614435
overlay_list:
14447-
a_exproverlay_placingsubstr_fromsubstr_for
14436+
a_exprPLACINGa_exprFROMa_exprFORa_expr
1444814437
{
14449-
$$ = list_make4($1,$2,$3,$4);
14438+
/* overlay(A PLACING B FROM C FOR D) is converted to overlay(A, B, C, D)*/
14439+
$$ = list_make4($1,$3,$5,$7);
1445014440
}
14451-
|a_exproverlay_placingsubstr_from
14441+
|a_exprPLACINGa_exprFROMa_expr
1445214442
{
14453-
$$ = list_make3($1,$2,$3);
14443+
/* overlay(A PLACING B FROM C) is converted to overlay(A, B, C)*/
14444+
$$ = list_make3($1,$3,$5);
1445414445
}
1445514446
;
1445614447

14457-
overlay_placing:
14458-
PLACINGa_expr
14459-
{$$ =$2; }
14460-
;
14461-
1446214448
/* position_list uses b_expr not a_expr to avoid conflict with general IN*/
14463-
1446414449
position_list:
1446514450
b_exprIN_Pb_expr{$$ = list_make2($3,$1); }
1446614451
|/*EMPTY*/{$$ = NIL; }
1446714452
;
1446814453

14469-
/* SUBSTRING() arguments
14470-
* SQL9x defines a specific syntax for arguments to SUBSTRING():
14471-
* o substring(text from int for int)
14472-
* o substring(text from int) get entire string from starting point "int"
14473-
* o substring(text for int) get first "int" characters of string
14474-
* o substring(text from pattern) get entire string matching pattern
14475-
* o substring(text from pattern for escape) same with specified escape char
14476-
* We also want to support generic substring functions which accept
14477-
* the usual generic list of arguments. So we will accept both styles
14478-
* here, and convert the SQL9x style to the generic list for further
14479-
* processing. - thomas 2000-11-28
14480-
*/
14454+
/* SUBSTRING() arguments*/
1448114455
substr_list:
14482-
a_exprsubstr_fromsubstr_for
14456+
a_exprFROMa_exprFORa_expr
1448314457
{
14484-
$$ = list_make3($1,$2,$3);
14458+
$$ = list_make3($1,$3,$5);
1448514459
}
14486-
|a_exprsubstr_forsubstr_from
14460+
|a_exprFORa_exprFROMa_expr
1448714461
{
14488-
/* not legal perSQL99, but might as well allow it*/
14489-
$$ = list_make3($1,$3,$2);
14462+
/* not legal perSQL, but might as well allow it*/
14463+
$$ = list_make3($1,$5,$3);
1449014464
}
14491-
|a_exprsubstr_from
14465+
|a_exprFROMa_expr
1449214466
{
14493-
$$ = list_make2($1,$2);
14467+
$$ = list_make2($1,$3);
1449414468
}
14495-
|a_exprsubstr_for
14469+
|a_exprFORa_expr
1449614470
{
14471+
/* not legal per SQL*/
14472+
1449714473
/*
1449814474
* Since there are no cases where this syntax allows
1449914475
* a textual FOR value, we forcibly cast the argument
@@ -14504,9 +14480,13 @@ substr_list:
1450414480
* is unknown or doesn't have an implicit cast to int4.
1450514481
*/
1450614482
$$ = list_make3($1, makeIntConst(1, -1),
14507-
makeTypeCast($2,
14483+
makeTypeCast($3,
1450814484
SystemTypeName("int4"), -1));
1450914485
}
14486+
/*
14487+
* We also want to support generic substring functions that
14488+
* accept the usual generic list of arguments.
14489+
*/
1451014490
| expr_list
1451114491
{
1451214492
$$ = $1;
@@ -14515,13 +14495,6 @@ substr_list:
1451514495
{ $$ = NIL; }
1451614496
;
1451714497

14518-
substr_from:
14519-
FROM a_expr{ $$ = $2; }
14520-
;
14521-
14522-
substr_for: FOR a_expr{ $$ = $2; }
14523-
;
14524-
1452514498
trim_list:a_expr FROM expr_list{ $$ =lappend($3, $1); }
1452614499
| FROM expr_list{ $$ = $2; }
1452714500
| expr_list{ $$ = $1; }

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