From 3b56d588fdb085d2ff70a106ddd4b2a1c319177f Mon Sep 17 00:00:00 2001
From: Guillermo Ramos
Date: Sun, 28 Apr 2019 20:05:38 +0200
Subject: [005#1] Comments

---
 005/ch1.pl | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
 mode change 100644 => 100755 005/ch1.pl

(limited to '005/ch1.pl')

diff --git a/005/ch1.pl b/005/ch1.pl
old mode 100644
new mode 100755
index 1d020a6..1c3436f
--- a/005/ch1.pl
+++ b/005/ch1.pl
@@ -3,15 +3,21 @@
 use strict;
 use warnings;
 
-# Functional implementation (tail-recursive)
 sub anagrams {
+	# Tail-recursive with accumulator; iterate over the word accumulating the
+	# anagrams that can be formed with the already-seen characters
 	sub iter {
+		# @acc contains the already computed anagrams
 		my ($word, @acc) = @_;
 		if (length($word) == 0) {
+			# Finished consuming word -> return accumulator
 			return @acc;
 		} else {
+			# Split the current word: first letter vs the rest
 			my ($head, $tail) = $word =~ /^(.)(.*)$/;
 			@_ = $tail; # Next word will be the tail of the previous one
+			# Compute new anagrams by inserting the current letter in all the
+			# positions of the previous anagrams
 			foreach my $anagram (@acc) {
 				for (my $i = 0; $i <= length($anagram); $i++) {
 					push(@_, $anagram);
@@ -21,7 +27,7 @@ sub anagrams {
 			goto &iter;
 		}
 	}
-	iter($_[0], (""));
+	iter(shift, (""));
 }
 
 for (@ARGV) {
-- 
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