diff options
| -rw-r--r-- | challenge-027/markus-holzer/README | 5 | ||||
| -rw-r--r-- | challenge-027/markus-holzer/perl6/ch-1.pl6 | 27 | ||||
| -rw-r--r-- | challenge-027/markus-holzer/perl6/ch-2.pl6 | 9 | ||||
| -rw-r--r-- | challenge-027/markus-holzer/perl6/lib/Scalar/History.pm6 | 93 |
4 files changed, 134 insertions, 0 deletions
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; + } +}
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