Task 2 done.

Adjusted some parts of task1 to allow task 2 to be able to use it as a
drawing engine

2 files changed, 48 insertions, 7 deletions

diff --git a/challenge-165/luca-ferrari/raku/ch-1.p6 b/challenge-165/luca-ferrari/raku/ch-1.p6
index 6ceb5bcc2b..c6d9146c83 100755
--- a/challenge-165/luca-ferrari/raku/ch-1.p6
+++ b/challenge-165/luca-ferrari/raku/ch-1.p6
@@ -12,18 +12,18 @@ sub MAIN( Str $filename = 'task1.svg' ) {
 
         if @elements.elems == 2 {
             # a point
-            my $point = circle =>  [ cx => @elements[ 0 ].Int,
-                                     cy => @elements[ 1 ].Int,
+            my $point = circle =>  [ cx => @elements[ 0 ].Num,
+                                     cy => @elements[ 1 ].Num,
                                      r => 5,
                                      fill => 'blue' ];
             @points.push: $point;
         }
         else {
             # a line
-            my $line = line => [ x1 => @elements[ 0 ].Int,
-                                 y1 => @elements[ 1 ].Int,
-                                 x2 => @elements[ 3 ].Int,
-                                 y2 => @elements[ 3 ].Int,
+            my $line = line => [ x1 => @elements[ 0 ].Num,
+                                 y1 => @elements[ 1 ].Num,
+                                 x2 => @elements[ 3 ].Num,
+                                 y2 => @elements[ 3 ].Num,
                                  stroke => 'magenta' ];
             @lines.push: $line;
         }
@@ -31,5 +31,5 @@ sub MAIN( Str $filename = 'task1.svg' ) {
     }
 
     $filename.IO.spurt( SVG.serialize:
-            svg => [ width => 100, height => 100, |@points, |@lines ] );
+            svg => [ width => 500, height => 500, |@points, |@lines ] );
 }
diff --git a/challenge-165/luca-ferrari/raku/ch-2.p6 b/challenge-165/luca-ferrari/raku/ch-2.p6
new file mode 100755
index 0000000000..babe880de4
--- /dev/null
+++ b/challenge-165/luca-ferrari/raku/ch-2.p6
@@ -0,0 +1,41 @@
+#!raku
+
+# Perl Weekly Challenge 165
+
+sub MAIN() {
+
+    my @input-points =
+                <333,129  39,189 140,156 292,134 393,52  160,166 362,122  13,193
+                 341,104 320,113 109,177 203,152 343,100 225,110  23,186 282,102
+                 284,98  205,133 297,114 292,126 339,112 327,79  253,136  61,169
+                 128,176 346,72  316,103 124,162  65,181 159,137 212,116 337,86
+                 215,136 153,137 390,104 100,180  76,188  77,181  69,195  92,186
+                 275,96  250,147  34,174 213,134 186,129 189,154 361,82  363,89 >;
+
+    # "decompose" the input into two elements arrays
+    my @points = @input-points.split( / \s+ / ).split( ',' ).split( / \s+ / ).map( *.Int ).rotor: 2;
+
+
+    # compute all the parts
+    my ( $m, $x, $y, $xy, $xx ) = 0,0,0,0,0;
+    $x  = [+] @points.map( { $_[0] } );
+    $y  = [+] @points.map( { $_[1] } );
+    $xy = [+] @points.map( { $_[0] * $_[1] } );
+    $xx = [+] @points.map( { $_[0] ** 2 } );
+    $m  = ( @points.elems * $xy - $x * $y ) / ( @points.elems * $xx - $x ** 2 );
+
+    my $b = 0;
+    $b = ( $y - $m * $x ) / @points.elems;
+
+    # compute the line start and end point
+    my @line;
+    @line.push: $_, $m * $_ + $b for 0,100;
+
+
+    # now I need to graph
+    my $task1 = run "raku", <raku/ch-1.p6 task2.svg>, :in, :err;
+    $task1.in.say: $_.join( ',' ) for @points;
+    $task1.in.say: @line.join( ',' );
+    $task1.in.close;
+    $task1.err.slurp.say;
+}