From: Tom Lane <tgl@sss.pgh.pa.us>
To: pgsql-hackers@postgreSQL.org
Subject: Inconsistent syntax for NumericOnly grammar production
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Date: Sun, 28 May 2017 17:16:24 -0400
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I noticed that gram.y has

NumericOnly:
            FCONST                              { $$ = makeFloat($1); }
            | '-' FCONST
                {
                    $$ = makeFloat($2);
                    doNegateFloat($$);
                }
            | SignedIconst                      { $$ = makeInteger($1); }
        ;

but

SignedIconst: Iconst                                { $$ = $1; }
            | '+' Iconst                            { $$ = + $2; }
            | '-' Iconst                            { $$ = - $2; }
        ;

The inconsistency here means that you can do, for example,

regression=# set random_page_cost = +4;
SET
regression=# set random_page_cost = 4.2;
SET

but not

regression=# set random_page_cost = +4.2;
ERROR:  syntax error at or near "4.2"
LINE 1: set random_page_cost = +4.2;
                                ^

That's weird enough in itself, and the problem is about to get more
widespread because the partbound_datum production depends on NumericOnly.

Any objections to allowing "+ FCONST" here?  I'm inclined to
fix this and back-patch it as well.

			regards, tom lane


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