bug in PLPGSQL

Your name		:	Andriy I Pilipenko
Your email address	:	bamby@marka.net.ua


System Configuration
---------------------
  Architecture (example: Intel Pentium)  	: Intel Pentium

  Operating System (example: Linux 2.0.26 ELF) 	: FreeBSD-4.2-STABLE

  PostgreSQL version (example: PostgreSQL-7.0):   PostgreSQL-7.0.3

  Compiler used (example:  gcc 2.8.0)	: gcc version 2.95.2 19991024 (release)


Please enter a FULL description of your problem:
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There is bug in PLPGSQL. If one of the parameters to plpgsql function is
null, other parameters becomes null too.


Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible: 
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First create function like this:

    CREATE FUNCTION f(varchar, varchar) RETURNS varchar
      AS '
    begin
	return ''first arg is: '' || $1;
    end;
    ' LANGUAGE 'plpgsql';

Then run query "SELECT f('some text', NULL)" and you will receive null
value.


If you know how this problem might be fixed, list the solution below:
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