Andrew Dunstan írta:
Zoltan Boszormenyi wrote:
Martijn van Oosterhout írta:
On Thu, Apr 19, 2007 at 11:19:40AM +0200, Zoltan Boszormenyi wrote:
The problem comes from cases like
colname coltype DEFAULT 5! GENERATED ...
Since b_expr allows postfix operators, it takes one more token of
lookahead than we have to tell if the default expression is "5!"
or "5!GENERATED ...".
ISTM that as long as:
colname coltype DEFAULT (5!) GENERATED ...
works I don't see why it would be a problem to require the parentheses
in this case. Postfis operators are not going to be that common here I
think.
Have a nice day,
You mean like this one?
------------------------------------------------------------------------
*** gram.y.old 2007-04-20 09:23:16.000000000 +0200
--- gram.y 2007-04-20 09:25:34.000000000 +0200
***************
*** 7550,7557 ****
{ $$ = (Node *) makeA_Expr(AEXPR_OP,
$2, $1, $3, @2); }
| qual_Op
b_expr %prec Op
{ $$ = (Node *) makeA_Expr(AEXPR_OP,
$1, NULL, $2, @1); }
! | b_expr
qual_Op %prec POSTFIXOP
! { $$ = (Node *) makeA_Expr(AEXPR_OP,
$2, $1, NULL, @2); }
| b_expr IS DISTINCT FROM
b_expr %prec IS
{
$$ = (Node *)
makeSimpleA_Expr(AEXPR_DISTINCT, "=", $1, $5, @2);
--- 7550,7557 ----
{ $$ = (Node *) makeA_Expr(AEXPR_OP,
$2, $1, $3, @2); }
| qual_Op
b_expr %prec Op
{ $$ = (Node *) makeA_Expr(AEXPR_OP,
$1, NULL, $2, @1); }
! | '(' b_expr qual_Op
')' %prec POSTFIXOP
! { $$ = (Node *) makeA_Expr(AEXPR_OP,
$3, $2, NULL, @3); }
| b_expr IS DISTINCT FROM
b_expr %prec IS
{
$$ = (Node *)
makeSimpleA_Expr(AEXPR_DISTINCT, "=", $1, $5, @2);
------------------------------------------------------------------------
This change alone brings 13 reduce/reduce conflicts.
No - that's not what you do. All you need to do is remove those 2
lines from the b_expr rules. The postfix rule will still be in a_expr
and the parenthesized bit is taken care of in the ( a_expr ) rule for
c_expr.
cheers
andrew
I just sent a new patch that marks GENERATED as %right,
which also solved the problem.
Best regards,
Zoltán
--
----------------------------------
Zoltán Böszörményi
Cybertec Geschwinde & Schönig GmbH
http://www.postgresql.at/
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