Merge pull request #3834 from drbaggy/master

Added some comments...

2 files changed, 31 insertions, 3 deletions

diff --git a/challenge-107/james-smith/perl/ch-1.pl b/challenge-107/james-smith/perl/ch-1.pl
index ea513d6508..753fe48f64 100644
--- a/challenge-107/james-smith/perl/ch-1.pl
+++ b/challenge-107/james-smith/perl/ch-1.pl
@@ -6,12 +6,36 @@ use warnings;
 use feature qw(say);
 use Test::More;
 
-## Generate the list of self descritpive numbers for base
-## < 7 - these are the ones that don't! follow the rules..
+## Generating self descriptive numbers can be split between
+## the case where n >= 7 and n < 7...
+## As we are asked for the first 3 these all exist in the case
+## where n<7....
+## 
+## To get the next we can write them (in base "n") as 
 ## All other numbers can be generated by the rule
-## n-4, 2, 1, 0 (n-7 times), 1, 0, 0, 0
+## "n-4", "2", "1", "0" (n-7 times), "1", "0", "0", "0"
+##
+## We loop through numbers starting 1 to see if they are self
+## descriptive.
+## To get the desciption of a number of length k, we loop from
+## 0..(k-1) counting the number of each digit in the string...
+## We can do this with a harcoded series of tr///s but in if
+## we want something dynamic we can write this as 
+##
+## @Q = m{($_)}g; $count = scalar @Q;
+##
+## we can do this in one line by using @{[ ]} to convert to the
+## list of matches to an array { subtle distinction here between 
+## lists and arrays! } and counting it by getting the scalar of
+## the array...
+##
+## The description is got by stitching those counts together...
+## We can do this in the one-line join q(), map below..
+## We just store it the list if the description and the number are
+## the same....
 
 my ($c,@res) = 0;
+
 while( ++$c && @res<3 ) {
   push @res, $c if $c == join q(),
     map { scalar @{[ $c=~m{($_)}g ]} } 0 .. -1 + length $c;
diff --git a/challenge-107/james-smith/perl/ch-2.pl b/challenge-107/james-smith/perl/ch-2.pl
index b9aa2cf69e..7895f22840 100644
--- a/challenge-107/james-smith/perl/ch-2.pl
+++ b/challenge-107/james-smith/perl/ch-2.pl
@@ -8,5 +8,9 @@ use feature qw(say);
 use lib '.';
 use Calc;
 
+## %{class}:: contains a list of the methods for the class,
+## so we can just dump these (to make it deterministic) we
+## sort first....
+
 say join "\n", sort keys %Calc::;