On Nov 7, 2007 9:23 PM, Panda-X <[EMAIL PROTECTED]> wrote:
> I have a script like this :
>
> sub This { print @_ }
>
> This ( -x => 100 ) ; # prints -x100
> This ( x => 100 ) ; # prints x100
>
> ##
> It seems that's something just as is.
> However, I saw many packages would like to use : -option => value
> So what's the point for this style ? Is there any specific reason for that ?
>
> Thanks,
> Panda-X
>
from perldoc perlop
Unary "-" performs arithmetic negation if the operand is numeric. If
the operand is an identifier, a string consisting of a minus sign con-
catenated with the identifier is returned. Otherwise, if the string
starts with a plus or minus, a string starting with the opposite sign
is returned. One effect of these rules is that -bareword is equivalent
to "-bareword".
Try
perl -le 'print - - "foo"'
and see what happens.
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