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Perl: the Markov chain saw

Re^2: ** operator in perl

by Random_Walk (Prior)
on Feb 03, 2009 at 12:55 UTC ( #740976=note: print w/ replies, xml ) Need Help??

in reply to Re: ** operator in perl
in thread ** operator in perl

I was puzzled by this one too ...

[me@ptmr]/home/me$ perl -le 'print -2 ** 4 ' # ** binds before - -16 [me@ptmr]/home/me$ perl -le 'print (-2) ** 4 ' # this puzzled me -2 [me@ptmr]/home/me$ perl -le 'print ((-2) ** 4)' # parenthesis force wh +at I want 16

but I guess print is handling the second case as a list followed by some irrelevance, do I have that about right ?

Update: Thanks Fletch now I have been enlightened! I last read perlfunc a long time ago and had not really absorbed it all at the time. Now I see the explanation print (something) something_else gives the warning print (...) interpreted as function because it looks like a function.


Pereant, qui ante nos nostra dixerunt!

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Re^3: ** operator in perl
by Fletch (Chancellor) on Feb 03, 2009 at 13:16 UTC

    print is a list operator, so the second parses as (print(-2))**4 and will produce a warning if you run with -w/warnings (Useless use of exponentiation (**) in void context at -e line 1.).

    Update: I mean it's not like perlfunc uses print as the example of precedence issues that can come up with list operators right in the second paragraph or anything . . .

    The cake is a lie.
    The cake is a lie.
    The cake is a lie.

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