Make hyperlinks clickable and comma

Hello.

Another question: when we write a link in a post immediately followed by a comma, the link created includes the comma.
So this often creates a 404 error.

Example:

blabla http://example.net/, blabla
is changed (in parser.php?) by
blabla <a href="http://example.net/,">http://example.net/,</a> blabla

instead of

blabla <a href="http://example.net/">http://example.net/</a>, blabla

Is there a solution to avoid this problem?

Thank you very much.