Expressions "[X0-9][0-9]{4}" and "[0-9X][0-9]{4}" not equivalent?

[email protected] Mon, 17 Feb 2003 12:16:46 +0100
Newsgroups gmane.comp.jakarta.regexp.user
Message-ID <OF4DB482F5.146ED412-ONC1256CD0.003D467C-C1256CD0.003DF5C9@hamburg.mummert.de>
Hello!

I have a problem with the following expression: [X0-9][0-9]{4}

IMHO the string X1234 should match the expression, but RegExp 1.2 does not
think so...;-(

When I use the expression: [0-9X][0-9]{4} instead, everthing works as
expected.

But IMHO the expressions should be equivalent.

What is wrong?

Regards
Oliver