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Math::Round::Var::round() takes no action when a number is not supplied

by metaperl (Curate)
on Aug 30, 2011 at 16:48 UTC ( #923265=perlquestion: print w/ replies, xml ) Need Help??
metaperl has asked for the wisdom of the Perl Monks concerning the following question:

Math::Round::Var has the following function:
###################################################################### +## =head2 round $number = $rounder->round($number); =cut sub round { my $self = shift; my $rnd = $self->{precision}; my $number = shift; return(sprintf("%0.${rnd}f", $number)); } # end subroutine round definition ###################################################################### +##
Please notice that there is neither a warning or exception if a number is not supplied. Is lack of a number argument an exception? Or should it throw a warning? Or is everything OK as it is?

Comment on Math::Round::Var::round() takes no action when a number is not supplied
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Re: Math::Round::Var::round() takes no action when a number is not supplied
by toolic (Chancellor) on Aug 30, 2011 at 17:04 UTC
    Did you try it? I get a warning:
    use Math::Round::Var; my $rnd = Math::Round::Var->new(0.01); # rounds to two decimal places: print $rnd->round(), "\n"; __END__ Use of uninitialized value in sprintf at .../Math/Round/Var.pm line 22 +9. 0.00
    The module's source code uses warnings.
      Did you try it?
      I shore did.
      I get a warning
      That warning came from Perl - the subroutine simply assumed you wanted to round the number zero - an undefined value was coerced to zero in context.
Re: Math::Round::Var::round() takes no action when a number is not supplied
by BrowserUk (Pope) on Aug 30, 2011 at 17:04 UTC

    It seems to raise a perfectly valid exception for me:

    sub round { my $self = shift; my $rnd = $self->{precision}; my $number = shift; return(sprintf("%0.${rnd}f", $number)); };; print round( {precision=>3}, 1.23456 );; 1.235 print round( {precision=>3}, 1 );; 1.000 print round( {precision=>3} );; Use of uninitialized value $number in sprintf at ... 0.000

    (Though quite why you'd use a module for this is beyond me?)


    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      It seems to raise a perfectly valid exception for me
      Well, a Perl-generated warning is not the same as a program-generated exception, and here we have only a Perl-generated warning.
        a Perl-generated warning is not the same as a program-generated exception,

        Really? So how do you handle them differently?


        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

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