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 -0000 2.65
--- plperl.sgml 3 May 2007 22:19:05 -0000
***************
*** 138,143 ****
--- 138,169 ----
</para>
<para>
+ Anything in a function argument or result that is not a reference is
+ a string, which is in the standard <productname>PostgreSQL</productname>
+ 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 <productname>PostgreSQL</productname> expects. For example,
+ here is how to convert an argument of type bytea into unescaped binary
+ data:
+
+ <programlisting>
+ my $arg = shift;
+ $arg =~ s!\\(\d{3})!chr(oct($1))!ge;
+ </programlisting>
+
+ and here is how to escape binary data for a return value of type bytea:
+
+ <programlisting>
+ $retval =~ s!([^ -~])!sprintf("\\%03o",ord($1))!ge;
+ return $retval;
+ </programlisting>
+
+ </para>
+
+ <para>
Perl can return <productname>PostgreSQL</productname> arrays as
references to Perl arrays. Here is an example:
