Solution to task 2

1 files changed, 37 insertions, 0 deletions

diff --git a/challenge-179/jo-37/perl/ch-2.pl b/challenge-179/jo-37/perl/ch-2.pl
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+#!/usr/bin/perl
+
+use v5.16;
+use List::MoreUtils 'minmax';
+use Math::Round 'round';
+
+die <<EOS unless @ARGV;
+usage: $0 N1 N2 ...
+
+N1 N2 ...
+    Numbers to be represented in a sparkline-like bar chart.
+
+EOS
+
+
+### Input and Output
+
+binmode STDOUT, ':utf8';
+say barchart(@ARGV);
+
+
+### Implementation
+
+# A vague solution for a vague task:  I didn't find any Unicode
+# symbols that could be used to produce sparklines.  Using
+# ${SEARCH_ENGINE} revealed some implementations that produce small
+# bar charts using Unicode symbols.  Following this approach.
+#
+# Starting with U+2581 ("\N{LOWER ONE EIGHTH BLOCK}"), there are eight
+# consecutive block symbols having a height of one to eight eights that
+# will be used here.  Returning a list of characters.
+
+sub barchart {
+    my ($min, $max) = minmax @_;
+    my $scale = 7 / (($max - $min) || 1);
+    map chr(0x2581 + round(($_ - $min) * $scale)), @_;
+}