zeroclickinfo-goodies/lib/DDG/Goodie/SigFigs.pm

package DDG::Goodie::SigFigs;
# ABSTRACT: Count the significant figures in a number.

use strict;
use DDG::Goodie;

triggers start => 'sigfigs', 'sigdigs', 'sf', 'sd', 'significant';

zci answer_type => "sig_figs";
zci is_cached => 1;

handle remainder => sub {
    $_ =~ s/^(figures|digits)\s*//g;
    return unless /^-?\d+(?:\.(?:\d+)?)?$/;
    $_ =~ s/-//;
    $_ =~ s/^0+//;
    my @arr = split('\\.', $_);
    my $v = @arr;
    my $len = 0;
    # there's a decimal
    unless ($v eq 1) {
        # the string doesn't have integers on the left
        # this means we can strip the leading zeros on the right
        if ($_ < 1) {
            $arr[1] =~ s/^0+//;
            $len = length $arr[1];
        }
        #there are integers on the left
        else {
            $len = length($arr[0]) + length($arr[1]);
        }
    }
    # no decimal
    else {
        # lose the trailing zeros and count
        $_ =~ s/\.?0*$//;
        $len = length $_;
    }
    return $len, structured_answer => {
        id   => 'sig_figs',
        name => 'Answer',
        data => {
            title    => "$len",
            subtitle => "Significant figures of $_",
        },
        templates => {
            group  => 'text',
            moreAt => 0,
        },
    };
};
1;