> What is the most "interesting" program that is restricted to
> use each ASCII character at most once?
The definition I chose was to check if a program (from @ARGV) contains
duplicate chars and printing a duplicate char iff it has one. This had a
sort of "quine"y feel to it and hence could be "interesting"(tm).
Unfortunately I was stumped, the best I can do is check the first line of
the file from @ARGV.
print <>=~m{(.)[^$/]*\1}
This is not what I'd hoped for when I started, but "print" kills so many
other useful tools, while, for, grep, map, until, if, unless, or, and. All
the /[a-z]+/ flow-control-like functions remaining to you are "do" and
"eval". Also it's far too easy to use up the 4 legal parens (), {} [] and
<>. The only other printing method I can easily see is via a "!#perl -p"
line which is illegal (I presume).
Can anyone improve the above so that it checks the whole of <>, not just one
line? Bonus points for an explicit multi-character message rather than undef
on failure.
Alistair
-----------------------------------------------------------------------
Registered Office:
Marks & Spencer p.l.c
Michael House, Baker Street,
London, W1U 8EP
Registered No. 214436 in England and Wales.
Telephone (020) 7935 4422
Facsimile (020) 7487 2670
www.marksandspencer.com
Please note that electronic mail may be monitored.
This e-mail is confidential. If you received it by mistake, please let us know and
then delete it from your system; you should not copy, disclose, or distribute its
contents to anyone nor act in reliance on this e-mail, as this is prohibited and may
be unlawful.
The registered office of Marks and Spencer Financial Services PLC, Marks and Spencer
Unit Trust Management Limited, Marks and Spencer Life Assurance Limited and Marks and
Spencer Savings and Investments Limited is Kings Meadow, Chester, CH99 9FB. These
firms are authorised and regulated by the Financial Services Authority.
