not operator operator..

[Norbert Nemec]

Sorry, I don't agree. != has been in C for ages and any C programmer
should therefore understand !in or !is.

Unlike in natural language text, source code does ! become more readable
when using words. It may slightly help the newbie, but it will get in
the way for everyday use.

The problem of Perl, for example, is not that it uses cryptic operators,
but that it uses too many, so that it takes a long time to know all of
them. the die-hard Perl users love that because it really improves
productivity, but any outsider is left in the rain.

For D, it is important to find the right measure which lies somewhere in
between Perl and Cobol:
http://www.csis.ul.ie/COBOL/Exercises/Exm-AcmeStockReorder/Prg-AcmeStockReorder.htm