Despatch Table

1 files changed, 32 insertions, 0 deletions

diff --git a/challenge-034/simon-proctor/perl6/ch-2.p6 b/challenge-034/simon-proctor/perl6/ch-2.p6
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index 0000000000..eae6b2131f
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+++ b/challenge-034/simon-proctor/perl6/ch-2.p6
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+#!/usr/bin/env perl6
+
+use v6;
+
+# Possible actions
+sub doubler ( Int $x ) { $x * 2 }
+sub halver ( Int $x ) { $x / 2 }
+sub squarer ( Int $x ) { $x * $x }
+sub reverser ( Int $x ) { $x.flip.Int }
+sub zeroer ( Int $x ) { 0 }
+
+# Despatch table
+my %commands = (
+    "double"  => &doubler,
+    "halve"   => &halver,
+    "square"  => &squarer,
+    "reverse" => &reverser,
+    "zero"    => &zeroer,
+);
+
+#| Help
+multi sub MAIN( Bool :h(:$help) where so * ) {
+    say $*USAGE;
+}
+
+#| Use despatch table to run the given command
+multi sub MAIN(
+    Str $command where { %commands{$command}:exists }, #= Valid command from double, halve, square, reverse, zero
+    Int() $value #= Value to apply command to
+) {
+    say "{$command}( {$value} ) => {%commands{$command}($value)}"; 
+}