Re: [PATCHES] document plperl argument and return value representation
Andrew Dunstan wrote: > > > Alvaro Herrera wrote: > >Andrew Dunstan wrote: > > > >>The attached docs patch makes clearer how arguments and return values in > >>pl/perl are escaped. This is to clarify the situation that Theo > >>Schlossnagle recently reported on -bugs. > >> > > > >I find the mix of arguments and results a bit confusing. Maybe you > >could put them in separate paragraphs. > > Is this better? Yup, looks very nice. This message also serves to test whether I removed the annoying Mail-Followup-To header. It was actually a _feature_ of mutt (followup_to, which fired when I replied to a list to which I'm subscribed), which I disabled. Sorry about that. ETOOMANYWHICH, sorry about that as well :-) -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 2: Don't 'kill -9' the postmaster
Re: [PATCHES] document plperl argument and return value representation
Andrew Dunstan <[EMAIL PROTECTED]> writes: > Is this better? I suggest bytea -> bytea, otherwise seems fine. regards, tom lane ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [PATCHES] document plperl argument and return value representation
Alvaro Herrera wrote: Andrew Dunstan wrote: The attached docs patch makes clearer how arguments and return values in pl/perl are escaped. This is to clarify the situation that Theo Schlossnagle recently reported on -bugs. I find the mix of arguments and results a bit confusing. Maybe you could put them in separate paragraphs. Is this better? I also took the opportunity to replace an unbalanced quote mark that was screwing up the syntax highlighting. cheers andrew Index: plperl.sgml === RCS file: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v retrieving revision 2.65 diff -c -r2.65 plperl.sgml *** plperl.sgml 3 May 2007 15:05:56 - 2.65 --- plperl.sgml 3 May 2007 23:44:04 - *** *** 138,150 Perl can return PostgreSQL arrays as references to Perl arrays. Here is an example: CREATE OR REPLACE function returns_array() RETURNS text[][] AS $$ ! return [['a"b','c,d'],['e\\f','g']]; $$ LANGUAGE plperl; select returns_array(); --- 138,180 +Anything in a function argument that is not a reference is +a string, which is in the standard PostgreSQL +external text representation for the relevant data type. In the case of +ordinary numeric or text types, Perl will just do the right thing and +the programmer will normally not have to worry about it. However, in +other cases the argument will need to be converted into a form that is +more usable in Perl. For example, here is how to convert an argument of +type bytea into unescaped binary +data: + + + my $arg = shift; + $arg =~ s!\\(\d{3})!chr(oct($1))!ge; + + + + + +Similarly, values passed back to PostgreSQL +must be in the external text representation format. For example, here +is how to escape binary data for a return value of type bytea: + + + $retval =~ s!([^ -~])!sprintf("\\%03o",ord($1))!ge; + return $retval; + + + + + Perl can return PostgreSQL arrays as references to Perl arrays. Here is an example: CREATE OR REPLACE function returns_array() RETURNS text[][] AS $$ ! return [['a"b','c,d'],['e\\f','g']]; $$ LANGUAGE plperl; select returns_array(); ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [PATCHES] document plperl argument and return value representation
Andrew Dunstan wrote: > > The attached docs patch makes clearer how arguments and return values in > pl/perl are escaped. This is to clarify the situation that Theo > Schlossnagle recently reported on -bugs. I find the mix of arguments and results a bit confusing. Maybe you could put them in separate paragraphs. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
[PATCHES] document plperl argument and return value representation
The attached docs patch makes clearer how arguments and return values in pl/perl are escaped. This is to clarify the situation that Theo Schlossnagle recently reported on -bugs. If there's no objection I will apply this. cheers andrew ? plperldoc.patch Index: plperl.sgml === RCS file: /cvsroot/pgsql/doc/src/sgml/plperl.sgml,v retrieving revision 2.65 diff -c -r2.65 plperl.sgml *** plperl.sgml 3 May 2007 15:05:56 - 2.65 --- plperl.sgml 3 May 2007 22:19:05 - *** *** 138,143 --- 138,169 +Anything in a function argument or result that is not a reference is +a string, which is in the standard PostgreSQL +external text representation for the relevant data type. In the case of +ordinary numeric or text types, Perl will just do the right thing and +the programmer will normally not have to worry about it. However, in +other cases the argument will need to be converted into a form that is +more usable in Perl, and the return result will need to be converted to +the form that PostgreSQL expects. For example, +here is how to convert an argument of type bytea into unescaped binary +data: + + + my $arg = shift; + $arg =~ s!\\(\d{3})!chr(oct($1))!ge; + + +and here is how to escape binary data for a return value of type bytea: + + + $retval =~ s!([^ -~])!sprintf("\\%03o",ord($1))!ge; + return $retval; + + + + + Perl can return PostgreSQL arrays as references to Perl arrays. Here is an example: ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings