Merge branch 'master' of https://github.com/manwar/perlweeklychallenge-club

44 files changed, 5769 insertions, 5330 deletions

diff --git a/challenge-026/markus-holzer/perl6/ch-1.p6 b/challenge-026/markus-holzer/perl6/ch-1.p6
index 70e6ceeaeb..ec85b011b2 100644
--- a/challenge-026/markus-holzer/perl6/ch-1.p6
+++ b/challenge-026/markus-holzer/perl6/ch-1.p6
@@ -25,7 +25,7 @@ multi sub infix:<\<∈>( Iterable $stones, Iterable $jewels ) returns Seq
 
 multi sub infix:<\<∈>( Str $stones, Str $jewels ) returns Str
 {
-    ( $stones.split( '', :skip-empty ) <∈ $jewels.split( '', :skip-empty ) ).join("")
+    ( $stones.comb <∈ $jewels.comb ).join("")
 }
 
 # And here we finally use it to solve the problem
diff --git a/challenge-027/joelle-maslak/perl6/ch-1.p6 b/challenge-027/joelle-maslak/perl6/ch-1.p6
new file mode 100755
index 0000000000..4a711c64b1
--- /dev/null
+++ b/challenge-027/joelle-maslak/perl6/ch-1.p6
@@ -0,0 +1,174 @@
+#!/usr/bin/env perl6
+use v6;
+
+use StrictClass;
+
+# This program finds the intersection of two lines.  While the word
+# "ends" is used, I'm instead assuming that these are true mathematical
+# lines, not line segments, so the intersection point may not be between
+# the two points that define the line.
+#
+# The first thing we need to do is to find the slope of each line.
+#
+# Edge case 1: If either line is not fully defined, we return an error.
+# This happens if both points are the same.
+#
+# Edge case 2: A vertical line can't be defined by the standard y = A × x₁ + C
+# equation.  In this case we handle it differently, see below.  We use ∞
+# for the slope in this case.
+#
+# To find the slope (of non-vertical lines), it's just rise / run, which is
+# easy to calculate.  For the constant, we need to solve this:
+#  y = Ax + C
+# A given point will define x and y, while the slope defines A, so we just
+# solve for C.  THus:
+#  C = y - Ax;
+#
+# If we have two equations: y₁ = A₁ × x₁ + C₁
+#                           y₂ = A₂ × x₂ + C₂
+#
+# We can find the intersection:
+#   1) If slope is identical, and constants differ, NO INTERSECTION
+#   2) If slope is identical, and constants are the same, this is the
+#      same line.
+#   3) If the slope is infinite of either line, just solve the other
+#      equation to determine y for that value of x.
+#   4) Otherwise, we're looking for the point where x₁=x₂ and y₁=y₂
+#      Thus, we can rewrite the equations as:
+#       y = A₁ × x + C₁
+#       y = A₂ × x + C₂
+#      We can solve this system for x:
+#       A₁ × x + C₁ = A₂ × x + C₂
+#      Rewritten:
+#       A₁ × x - A₂ × x = C₂ - C₁ 
+#      Rewritten:
+#       (A₁ - A₂) × x = C₂ - C₁ 
+#       x = (C₂ - C₁) ÷ (A₁ - A₂) 
+#      Once we have x, we can solve for y by plugging into either of the
+#      original equations.
+#
+
+class Point does StrictClass {
+    has Real:D $.x is rw is required;
+    has Real:D $.y is rw is required;
+
+    method from-string(Str:D $point-str is copy -->Point:D) {
+        $point-str ~~ s:s/^ '(' [.*] ')' $/$0/;  # Remove parens
+        my (Real:D $x, Real:D $y) = $point-str.split(',').map( +* );
+
+        return Point.new(:$x, :$y);
+
+        CATCH {
+            # We must have been passed a bad point
+            die "$point-str is an invalid point definition";
+        }
+    }
+}
+
+class Line does StrictClass {
+    has Real:D  $.slope is rw is required;
+    has Point:D $.point is rw is required;  # Any valid point on the line
+
+    method solve-for-x(Real:D $y -->Real:D) {
+        # Vertical line exception
+        return $.point.x if $.slope == ∞;
+
+        # Horizontal line exception
+        if $.slope == 0 {
+            die "Cannot solve for $y" if $.point.y ≠ $y;
+        }
+
+        return ($y - self.y-offset) ÷ $.slope;
+    }
+
+    method solve-for-y(Real:D $x -->Real:D) {
+        # Horizontal line exception
+        return $.point.y if $.slope == 0;
+
+        # Vertical line exception
+        if $.slope == ∞ {
+            die "Cannot solve for $x" if $.point.x ≠ $x;
+        }
+
+        # Lines between horizontal and ertical
+        return $.slope × $x + self.y-offset;
+    }
+
+    method y-offset(-->Real:D) {
+        # Vertical line exception
+        return ∞ if $.slope == ∞;
+
+        # Non-vertical lines
+        return $.point.y - $.slope × $.point.x;
+    }
+
+    method intersection(Line:D $line -->Point:D) {
+        die "Lines are the same" if self eqv $line;
+        die "Lines do not intersect" if self.slope == $line.slope;
+
+        # If either line is vertical
+        if self.slope == ∞ {
+            return Point.new(:x(self.point.x),  :y($line.solve-for-y(self.point.x)));
+        } elsif $line.slope == ∞ {
+            return Point.new(:x($line.point.x), :y(self.solve-for-y($line.point.x)));
+        }
+
+        # We're finding a normal intersection
+        my $x = ($line.y-offset - self.y-offset) ÷ (self.slope - $line.slope);
+        my $y = self.solve-for-y($x);
+
+        return Point.new(:$x, :$y);
+    }
+
+    # We need an eqv that works
+    CORE::<&infix:<eqv>>.add_dispatchee(
+        multi sub infix:<eqv> (Line:D $line1, Line:D $line2 -->Bool) {
+            return False if $line1.slope ≠ $line2.slope;
+
+            # Are both vertical?
+            if $line1.slope == ∞ and $line2.slope == ∞ {
+                return $line1.point.x == $line2.point.x;
+            }
+
+            # All other lines
+            return $line1.point.y == $line2.solve-for-y($line1.point.x);
+        }
+    );
+
+    method from-points(Point:D $point1, Point:D $point2 -->Line:D) {
+        # Handle same point
+        die "Lines must be defined with two different points" if $point1 eqv $point2;
+
+        # Handle vertical line exception
+        return Line.new(:point($point1), :slope(∞)) if $point1.x == $point2.x;
+
+        # Handle other lines.
+        my $slope = ($point1.y - $point2.y) ÷ ($point1.x - $point2.x);
+        return Line.new(:point($point1), :$slope);
+    }
+}
+
+# point1 and point2 define a line.  You can determine which line by the
+# letter
+sub MAIN(Str:D $point1a, Str:D $point2a, Str:D $point1b, $point2b) {
+    my $line1 = Line.from-points(
+        Point.from-string($point1a),
+        Point.from-string($point2a),
+    );
+    my $line2 = Line.from-points(
+        Point.from-string($point1b),
+        Point.from-string($point2b),
+    );
+
+    if $line1 eqv $line2 {
+        say "The two lines are the same";
+    } elsif $line1.slope == $line2.slope {
+        say "The two lines don't intersect";
+    } else {
+        my $intersection = $line1.intersection($line2);
+        say "The lines intersect at ({ $intersection.x },{ $intersection.y })";
+    }
+
+    return;
+}
+
diff --git a/challenge-027/joelle-maslak/perl6/ch-2.p6 b/challenge-027/joelle-maslak/perl6/ch-2.p6
new file mode 100755
index 0000000000..8183d58d79
--- /dev/null
+++ b/challenge-027/joelle-maslak/perl6/ch-2.p6
@@ -0,0 +1,59 @@
+#!/usr/bin/env perl6
+use v6;
+
+# Limitation: With nested data structures, we only store the version as
+# it existed at the time of setting the proxy (I.E. an array that
+# changes *after* the proxy variable is set will only be stored as the
+# initial value of the array.
+class History {
+    has @!hist;
+    has $!data;
+
+    method get-proxy() is rw {
+        my $data    := $!data;
+        my $history := @!hist;
+        Proxy.new(
+            FETCH => method ()     { $data },
+            STORE => method ($val) { $data = $val; $history.push( $data.clone ) },
+        );
+    }
+
+    method history() {
+        my @h = @!hist;
+        @h.push: $!data;
+        return @h;
+    }
+}
+
+sub MAIN() {
+    my $hist = History.new;
+    my $x := $hist.get-proxy();
+
+    $x  = 10;
+    $x  = 20;
+    $x -= 5;
+
+    my $y := $hist.get-proxy();  # It's okay to have multiple proxies
+    $y++;
+    $y = 'Foo!';
+
+    # And to show that the second proxy is using the same values
+    $x ~= ' Bar!';
+
+    # A new instance of history should be independnet.
+    my $hist2 = History.new;
+    my $z := $hist2.get-proxy();
+    $z = 3;  # Won't show up in history for $hist.
+
+    # And we just set the original history, the one we log, to a new
+    # value
+    $x = 'Baz.';
+
+    # Also let's do an array.
+    my @a = 1,2,3;
+    $x = @a;
+
+    say join("\n", $hist.history».perl);
+}
+
+
diff --git a/challenge-027/markus-holzer/README b/challenge-027/markus-holzer/README
index 64aaa503e7..2000655be2 100644
--- a/challenge-027/markus-holzer/README
+++ b/challenge-027/markus-holzer/README
@@ -1 +1,6 @@
 Solutions by Markus Holzer.
+
+Solution #2 only works on the current developer branch and uses a module I wrote 
+Please see https://github.com/holli-holzer/perl6-Scalar-History
+To be on CPAN soon
+
diff --git a/challenge-027/markus-holzer/perl6/ch-1.pl6 b/challenge-027/markus-holzer/perl6/ch-1.pl6
new file mode 100644
index 0000000000..4c7e3b5448
--- /dev/null
+++ b/challenge-027/markus-holzer/perl6/ch-1.pl6
@@ -0,0 +1,27 @@
+multi sub MAIN( Int:D $x1, Int:D $y1, Int:D $x2, Int:D $y2, Int:D $x3, Int:D $y3, Int:D $x4, Int:D $y4 )
+{
+    with intersection( $x1, $y1, $x2, $y2, $x3, $y3, $x4, $y4 ) -> ($x, $y) 
+    { 
+        say "The intersection is at $x, $y.";
+    } 
+    else 
+    { 
+        say .exception.message;
+    }
+}
+
+
+sub intersection( Int \x1, Int \y1, Int \x2, Int \y2, Int \x3, Int \y3, Int \x4, Int \y4 )
+{
+    CATCH { default { fail "Lines are parallel or identical" } }
+    
+    return (
+        eager # potential for division by zero, 
+            ( (x1 * y2 - y1 * x2 ) * (x3 - x4) - (x1 - x2) * (x3 * y4 - y3*x4) ) div
+            ( (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4) ),
+
+        eager # without eager, laziness will bite us later
+            ( (x1 * y2 - y1 * x2) * (y3 - y4) - (y1 -y2) * (x3*y4 - y3 * x4) ) div
+            ( (x1 - x2) * (y3 - y4) - (y1 - y2) * (x2 - x4) )
+    );
+}
diff --git a/challenge-027/markus-holzer/perl6/ch-2.pl6 b/challenge-027/markus-holzer/perl6/ch-2.pl6
new file mode 100644
index 0000000000..d3bea23017
--- /dev/null
+++ b/challenge-027/markus-holzer/perl6/ch-2.pl6
@@ -0,0 +1,9 @@
+use Test;
+use Scalar::History; # See the README
+
+my Int $x := Scalar::History.create(10, Int);
+$x = 20;
+$x -= 5;
+
+ok( $x == 15 );
+is-deeply( $x.VAR.get-history, (10, 20) );
\ No newline at end of file
diff --git a/challenge-027/markus-holzer/perl6/lib/Scalar/History.pm6 b/challenge-027/markus-holzer/perl6/lib/Scalar/History.pm6
new file mode 100644
index 0000000000..13c8346424
--- /dev/null
+++ b/challenge-027/markus-holzer/perl6/lib/Scalar/History.pm6
@@ -0,0 +1,93 @@
+use Test;
+
+my $minumum-version = Version.new('2019.07.1.357.gd.00674.b.31');
+
+die "Scalar::History requires $minumum-version or later"
+    if ( $*PERL.compiler.version cmp $minumum-version ) == Less;
+
+class Scalar::History::Proxy is Proxy
+{
+    has @!history;
+    has $!position;
+
+    # This is needed for now since the standard ways
+    # like assigning in the `has` statement, TWEAK
+    # and BUILD don't work with `Proxy`
+
+    method new( :&FETCH!, :&STORE!, *%_ ) is raw
+    {
+        my $self := self.Proxy::new( :&FETCH, :&STORE );
+        $self.VAR.TWEAK( |%_ );
+        $self
+    }
+
+    method TWEAK( :$!position = 0 ) {
+        # yadayada
+    }
+
+    method current-value( \SELF: )
+    {
+        @!history[ $!position ]
+    }
+
+    method latest-value( \SELF: )
+    {
+        @!history[ *-1 ]
+    }
+
+    method get-history( \SELF: Bool :$all = False )
+    {
+        my $to-index = $all ?? @!history.elems - 1 !! $!position;
+        @!history[ ^$to-index ]
+    }
+
+    method reset-history( \SELF: )
+    {
+        @!history = ();
+        $!position = 0;
+    }
+
+    method forward-history( \SELF: $steps )
+    {
+        $!position = $!position + $steps;
+        $!position = @!history.elems - 1
+            if $!position >= @!history.elems;
+        $!position;
+    }
+
+    method rewind-history( \SELF: $steps )
+    {
+        $!position = $!position - $steps;
+        $!position = 0
+            if $!position < 0;
+        $!position;
+    }
+
+    method store-value( \SELF: $new-value, $register-duplicates )
+    {
+        # Forget stuff after rewind
+        if @!history.elems > $!position + 1
+        {
+            @!history.splice( $!position + 1 );
+        }
+
+        if !($new-value eqv SELF.current-value) || $register-duplicates
+        {
+            @!history.push( $new-value );
+            $!position = @!history.elems - 1;
+        }
+    }
+}
+
+class Scalar::History
+{
+    method create( $value, ::T $type = Any, Bool :$register-duplicates = False )
+    {
+        return-rw Scalar::History::Proxy.new(
+            FETCH => method ( \SELF: ) {
+                SELF.current-value() },
+            STORE => method ( \SELF: T $new-value ) {
+                SELF.store-value( $new-value, $register-duplicates ); }
+        ) = $value;
+    }
+}
\ No newline at end of file
diff --git a/challenge-027/yet-ebreo/perl6/ch-2.p6 b/challenge-027/yet-ebreo/perl6/ch-2.p6
new file mode 100644
index 0000000000..52f254c429
--- /dev/null
+++ b/challenge-027/yet-ebreo/perl6/ch-2.p6
@@ -0,0 +1,23 @@
+# Write a script that allows you to capture/display historical data. It could be an object or a scalar. For example
+# my $x = 10; $x = 20; $x -= 5;
+# After the above operations, it should list $x historical value in order.
+
+class hist {
+    has @.history;
+    has $!var handles <Str gist FETCH Numeric>;
+    method STORE($val) {
+        push @.history, $val;
+        $!var = $val;
+    }
+}
+
+my \x = hist.new(history => []);
+
+x = 10; 
+x = 20; 
+x -= 5;
+x = 3.1416;
+x = Q[a quick brown fox jumps over the lazy dog];
+x = 1e3;
+x*= sqrt 3;
+.say  for x.history;
diff --git a/stats/pwc-challenge-001.json b/stats/pwc-challenge-001.json
index 8c87056def..d54dea2b81 100644
--- a/stats/pwc-challenge-001.json
+++ b/stats/pwc-challenge-001.json
@@ -1,9 +1,9 @@
 {
-   "xAxis" : {
-      "type" : "category"
+   "chart" : {
+      "type" : "column"
    },
-   "legend" : {
-      "enabled" : 0
+   "title" : {
+      "text" : "Perl Weekly Challenge - 001"
    },
    "drilldown" : {
       "series" : [
@@ -18,52 +18,52 @@
                   1
                ]
             ],
-            "name" : "Adam Russell",
-            "id" : "Adam Russell"
+            "id" : "Adam Russell",
+            "name" : "Adam Russell"
          },
          {
+            "name" : "Ailbhe Tweedie",
             "data" : [
                [
                   "Perl 5",
                   1
                ]
             ],
-            "id" : "Ailbhe Tweedie",
-            "name" : "Ailbhe Tweedie"
+            "id" : "Ailbhe Tweedie"
          },
          {
             "id" : "Alex Daniel",
-            "name" : "Alex Daniel",
             "data" : [
                [
                   "Perl 6",
                   2
                ]
-            ]
+            ],
+            "name" : "Alex Daniel"
          },
          {
+            "name" : "Andrezgz",
+            "id" : "Andrezgz",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ],
-            "name" : "Andrezgz",
-            "id" : "Andrezgz"
+            ]
          },
          {
+            "name" : "Antonio Gamiz",
             "data" : [
                [
                   "Perl 6",
                   2
                ]
             ],
-            "name" : "Antonio Gamiz",
             "id" : "Antonio Gamiz"
          },
          {
-            "id" : "Arne Sommer",
             "name" : "Arne Sommer",
+            "id" : "Arne Sommer",
             "data" : [
                [
                   "Perl 5",
@@ -81,43 +81,43 @@
          },
          {
             "name" : "Arpad Toth",
-            "id" : "Arpad Toth",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ]
+            ],
+            "id" : "Arpad Toth"
          },
          {
             "name" : "Athanasius",
-            "id" : "Athanasius",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ]
+            ],
+            "id" : "Athanasius"
          },
          {
+            "name" : "Bob Kleemann",
+            "id" : "Bob Kleemann",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ],
-            "id" : "Bob Kleemann",
-            "name" : "Bob Kleemann"
+            ]
          },
          {
-            "name" : "Daniel Mantovani",
-            "id" : "Daniel Mantovani",
             "data" : [
                [
                   "Perl 5",
                   1
                ]
-            ]
+            ],
+            "id" : "Daniel Mantovani",
+            "name" : "Daniel Mantovani"
          },
          {
             "data" : [
@@ -130,12 +130,11 @@
                   1
                ]
             ],
-            "name" : "Dave Cross",
-            "id" : "Dave Cross"
+            "id" : "Dave Cross",
+            "name" : "Dave Cross"
          },
          {
             "name" : "Dave Jacoby",
-            "id" : "Dave Jacoby",
             "data" : [
                [
                   "Perl 5",
@@ -145,7 +144,8 @@
                   "Blog",
                   1
                ]
-            ]
+            ],
+            "id" : "Dave Jacoby"
          },
          {
             "data" : [
@@ -164,8 +164,8 @@
                   2
                ]
             ],
-            "name" : "Doug Schrag",
-            "id" : "Doug Schrag"
+            "id" : "Doug Schrag",
+            "name" : "Doug Schrag"
          },
          {
             "data" : [
@@ -178,18 +178,18 @@
                   2
                ]
             ],
-            "name" : "Dr James A. Smith",
-            "id" : "Dr James A. Smith"
+            "id" : "Dr James A. Smith",
+            "name" : "Dr James A. Smith"
          },
          {
             "id" : "Duncan C. White",
-            "name" : "Duncan C. White",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ]
+            ],
+            "name" : "Duncan C. White"
          },
          {
             "data" : [
@@ -202,48 +202,47 @@
             "name" : "Eddy HS"
          },
          {
+            "name" : "Finley",
             "data" : [
                [
                   "Perl 6",
                   2
                ]
             ],
-            "name" : "Finley",
             "id" : "Finley"
          },
          {
-            "id" : "Fred Zinn",
-            "name" : "Fred Zinn",
             "data" : [
                [
                   "Perl 5",
                   1
                ]
-            ]
+            ],
+            "id" : "Fred Zinn",
+            "name" : "Fred Zinn"
          },
          {
             "id" : "Freddie B",
-            "name" : "Freddie B",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ]
+            ],
+            "name" : "Freddie B"
          },
          {
+            "name" : "Gustavo Chaves",
             "data" : [
                [
                   "Perl 5",
                   1
                ]
             ],
-            "name" : "Gustavo Chaves",
             "id" : "Gustavo Chaves"
          },
          {
             "name" : "JJ Merelo",
-            "id" : "JJ Merelo",
             "data" : [
                [
                   "Perl 6",
@@ -253,9 +252,12 @@
                   "Blog",
                   1
                ]
-            ]
+            ],
+            "id" : "JJ Merelo"
          },
          {
+            "name" : "Jaldhar H. Vyas",
+            "id" : "Jaldhar H. Vyas",
             "data" : [
                [
                   "Perl 5",
@@ -265,19 +267,17 @@
                   "Perl 6",
                   2
                ]
-            ],
-            "name" : "Jaldhar H. Vyas",
-            "id" : "Jaldhar H. Vyas"
+            ]
          },
          {
+            "name" : "Jeff",
+            "id" : "Jeff",
             "data" : [
                [
                   "Perl 5",
                   2
                ]
-            ],
-            "id" : "Jeff",
-            "name" : "Jeff"
+            ]
          },
          {
             "data" : [
@@ -304,7 +304,6 @@
             "name" : "Jim Bacon"
          },
          {
-            "id" : "Jo Christian Oterhals",
             "name" : "Jo Christian Oterhals",
             "data" : [
                [
@@ -319,9 +318,11 @@
                   "Blog",
                   1
                ]
-            ]
+            ],
+            "id" : "Jo Christian Oterhals"
          },
          {
+            "name" : "Joelle Maslak",
             "data" : [
                [