Question

Context: ActiveState Perl:
This is perl 5, version 12, subversion 4 (v5.12.4) built for MSWin32-x86-multi-thread

>perl -Mbignum=l -e "print 2 ** 32"
4294967296

>perl -Mbignum=l -e "print -2 ** 32"
-4294967296

Then I got to thinking, maybe I need to delimit the negative two.

>perl -Mbignum=l -e "print (-2) ** 32"
-2

Finally figured it out.

>perl -Mbignum=l -e "print ((-2) ** 32)"
4294967296

So how come all the parentheses?

Answer 1

This thread covers both of your questions (you have to go down a little to find the part corresponding to print (-2) ** 32).

Summarizing what is there:

• For your first issue (perl -Mbignum=l -e "print -2 ** 32"): in Perl exponentiation has higher precedence than unary negation.

• For the second issue (perl -Mbignum=l -e "print (-2) ** 32"): the key is the following warning in the documentation for print.

  Also be careful not to follow the print keyword with a left parenthesis unless you want the corresponding right parenthesis to terminate the arguments to the print–interpose a + or put parentheses around all the arguments.