| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | 孤傲小二～阿沐 <2903807914(at)qq(dot)com> |
| Cc: | pgsql-general <pgsql-general(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: I added a √ operator, the sqrt function is still used internally, but now there is a problem, it affects the := and .. operators of the database |
| Date: | 2021-11-12 05:42:08 |
| Message-ID: | 1648741.1636695728@sss.pgh.pa.us |
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| Lists: | pgsql-general |
"=?gb18030?B?ucKwwdChtv6hq7Ci4+U=?=" <2903807914(at)qq(dot)com> writes:
> # Description of Requirement:
> 1¡¢select ¡Ì num1; function
> 2¡¢The value of num1 is required to be: [0,9223372036854775807]
> 3¡¢¡Ì The operation does not allow decimals
Looks suspiciously like a homework assignment.
> I have now developed this feature on the PostgreSQL 14.0 kernel! But it affects the original function of the database:
> # Affected place
> 1¡¢ := assignment operator
> 2¡¢ Operator in 1..10
Today's lesson is: read the comments on the code you're modifying.
Notably on gram.y's list of "non keyword" tokens:
* Non-keyword token types. These are hard-wired into the "flex" lexer.
* They must be listed first so that their numeric codes do not depend on
* the set of keywords. PL/pgSQL depends on this so that it can share the
* same lexer. If you add/change tokens here, fix PL/pgSQL to match!
Since you didn't do that, PL/pgSQL is confused about the token codes
in use for DOT_DOT and so on.
regards, tom lane