Merge pull request #27 from bracteatus/master

Perl Weekly Challenge 002

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diff --git a/challenge-002/jaime/README.md b/challenge-002/jaime/README.md
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+# Perl Weekly Challenge 002
+By Jaime; [@tortsnare on Twitter](https://twitter.com/tortsnare).
+
+Straightforward solutions in Perl 5 that use no imports.
+The user selects a conversion and feeds in numbers, in a UNIX-like approach.
+
+# perl5/ch-1.pl
+Write a script or one-liner to remove leading zeros from positive numbers.
+
+## Solution
+Run as a single shell one-liner:
+`perl -E 'while(<>) {s/^0+//;print;}' # interactively reads numbers`
+
+or pipe the numbers, example:
+`cat number_list | perl -E 'while(<>) {s/^0+//;print;}`
+
+# perl5/ch-2.pl
+Write a script that can convert integers to and from a base35 representation,
+using the characters 0-9 and A-Y.
+
+## Solution
+Convert between base10 and base35 strings.
+User flags toggle the conversion operation at runtime.
+
+## Convert base10 into base35
+`cat integer_list | perl ch-2.pl`
+
+## Convert base35 into base10
+`cat base35_list | perl ch-2.pl --base35-to-int`
diff --git a/challenge-002/jaime/perl5/ch-1.pl b/challenge-002/jaime/perl5/ch-1.pl
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+# Challenge #1
+#
+# Write a script or one-liner to remove leading zeros from positive numbers.
+
+## Using Perl 5:
+while (<>) { # read positive number as lines from stdin
+  s/^0+//; # remove leading zeros from each line
+  print; # show updated number
+}
+
+## as a single shell one-liner:
+# $ perl -E 'while(<>) {s/^0+//;print;}' # interactively reads numbers
+
+# or pipe the numbers to format, example:
+# $ cat numbers_list | perl -E 'while(<>) {s/^0+//;print;}'
diff --git a/challenge-002/jaime/perl5/ch-2.pl b/challenge-002/jaime/perl5/ch-2.pl
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+# Challenge #2
+#
+# Write a script that can convert integers to and from a base35 representation,
+#  using the characters 0-9 and A-Y. Dave Jacoby came up with nice description
+#  about base35, in case you needed some background.
+
+my @numnums = (0..9,'A'..'Y'); # map integers 0..34 into base35 #TODO use actual map instead, for reverse lookup.
+
+sub intTo35 {
+    # convert positive integer into base35 string.
+    return "0" if (0 == $_); # special case; log(0) is undefined.
+
+    my @result = ();
+    for my $i (0..(int(log($_)/log(35)))) { # iterate from int(log_35($_)) to 0.
+      push @result, @numnums[$_ % 35]; # map value of respective power of 35.
+      $_ /= 35; # prepare for next power of 35.
+    }
+
+    return join "", reverse @result; # string encoding $_ as base35.
+}
+
+sub intFrom35 {
+    # convert positive base35 string into integer
+    my ($result,$p) = (0,0);
+    for my $d (reverse (split //)) { # match each digit to its respective power of 35.
+      my $e = 0; # TODO reverse map lookup would reduce this whole section.
+      for my $num (@numnums) {
+        last if ($d eq $num); # found respective int multiplier.
+        $e++;
+      }
+      $result += $e * (35**($p++)); # appraise base35 digit as int.
+    }
+    return $result; # int of decoded base35 string.
+}
+
+# default to conversion from int into base35,
+#  flag --base35-to-int to convert base35 into int.
+$_ = shift;
+my $converter = ($_ eq "--base35-to-int") ? "intFrom35" : "intTo35";
+print "# read numbers (also negative) from stdin.\n# use --base-35-to-int to convert from base35 into int.\n";
+while(<>) {
+    chomp $_; # read positive or negative numbers as lines from stdin
+    print "$converter($_) = @{[ ( s/^-// ? -(eval $converter) : (eval $converter) ) ]}\n"; # run selected conversion, appending sign.
+}