stub for wavelength conversion

lib/DDG/Goodie/Wavelength.pm

@@ -0,0 +1,58 @@
+package DDG::Goodie::Wavelength;
+use utf8;
+# ABSTRACT: Frequency to wavelength
+
+use DDG::Goodie;
+
+use constant SPEED_OF_LIGHT => 299792458; #meters/second
+use constant MULTIPLIER => {
+     hz => 1,
+    khz => 10**3,
+    mhz => 10**6,
+    ghz => 10**9,
+    thz => 10**12
+};
+
+zci answer_type => "wavelength";
+zci is_cached   => 1;
+
+# Metadata.  See https://duck.co/duckduckhack/metadata for help in filling out this section.
+name "Wavelength";
+description "Frequency to Wavelength translation";
+primary_example_queries "λ 2.4GHz", "144.39 MHz wavelength","lambda 1500kHz";
+category "physical_properties";
+topics "math", "science", "special_interest";
+code_url "https://github.com/nebulous/zeroclickinfo-goodies/blob/master/lib/DDG/Goodie/Wavelength.pm";
+attribution  github => ["nebulous", "John Lifsey"],
+               cpan => "nebulous",
+            twitter => "aresweet";
+
+# Triggers
+triggers any => "λ", "wavelength", "lambda";
+
+# Handle statement
+handle remainder => sub {
+	my ($freq,$units) = m/([\d\.]+)\s*((k|m|g|t)?hz)/i;
+    return unless $freq and $units;
+
+    my $mul     = MULTIPLIER->{lc($units)};
+    my $hz_freq = $freq * $mul;
+    
+    my $output_value = (SPEED_OF_LIGHT / $hz_freq);
+    my $output_units = 'Meters';
+    
+    # Fairly common to express higher freqs in cm/mm. 
+    # eg UHF 70cm band, microwave 3mm, etc
+    if ($output_value<1) {
+        $output_units = 'Centimeters';
+        $output_value *= 100;
+        if ($output_value<1) {
+            $output_units = 'Millimeters';
+            $output_value *= 10;
+        }
+    }
+         
+    return "$freq $units λ = $output_value $output_units";
+};
+
+1;

t/Wavelength.t

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+#!/usr/bin/env perl
+
+use strict;
+use warnings;
+use Test::More;
+use DDG::Test::Goodie;
+use utf8;
+
+zci answer_type => "wavelength";
+zci is_cached   => 1;
+
+ddg_goodie_test(
+    [qw( DDG::Goodie::Wavelength )],
+    # At a minimum, be sure to include tests for all:
+    # - primary_example_queries:
+     '1Hz wavelength' => test_zci("1 Hz λ = 299792458 Meters"),
+    'lambda 0.001kHz' => test_zci('0.001 kHz λ = 299792458 Meters'),
+
+    'λ 2.4GHz' => test_zci('1 Hz λ = 299792458 Meters'),
+    #'144.39 MHz wavelength' => test_zci(''),
+    #'lambda 1500kHz' => test_zci(''),
+    # Try to include some examples of queries on which it might
+    # appear that your answer will trigger, but does not.
+    'lambda lambda lambda' => undef,
+);
+
+done_testing;