Use iterators to handle take_while/skip_while/concat instead of using…

… element_at, thus avoiding needing to deal with exception handling.
tobyink · Apr 7, 2021 · c2da9ba · c2da9ba
1 parent 2eb321c
commit c2da9ba
Show file tree

Hide file tree

Showing 2 changed files with 40 additions and 51 deletions.
diff --git a/lib/LINQ/Collection.pm b/lib/LINQ/Collection.pm
@@ -190,27 +190,17 @@ sub take_while {
 	my $self    = shift;
 	my $filter  = LINQ::Util::Internal::assert_code( @_ );
 	my $stopped = 0;
-	my $idx     = 0;
+	my $iter    = $self->to_iterator;
 
 	require LINQ;
-	require LINQ::Iterator;
-	'LINQ::Iterator'->new( sub {
-		local ( $@, $_ );
-		my $next;
-		my $ok = eval { $next = $self->element_at( $idx ); not $stopped };
-		my $e  = $@;
-		if ( $ok and $filter->( $_ = $next ) ) {
-			++$idx;
-			return $next;
-		}
-		if ( defined $e and not $ok ) {
-			require Scalar::Util;
-			die( $e ) unless Scalar::Util::blessed( $e );
-			die( $e ) unless $e->isa( 'LINQ::Exception::NotFound' );
-			die( $e ) unless $e->collection == $self;
+	LINQ::Util::Internal::create_linq( sub {
+		return LINQ::END() if $stopped;
+		my @got = $iter->();
+		if ( ! @got or ! $filter->( $_ = $got[0] ) ) {
+			$stopped++;
+			return LINQ::END();
 		}
-		$stopped = 1;
-		return LINQ::END();
+		return $got[0];
 	} );
 } #/ sub take_while
 
@@ -221,46 +211,47 @@ sub skip {
 }
 
 sub skip_while {
-	my $self     = shift;
-	my $filter   = LINQ::Util::Internal::assert_code( @_ );
-	my $skipping = 1;
-	$self->where(
-		sub {
-			$skipping = 0
-				if $skipping
-				&& !$filter->( $_ );
-			not $skipping;
-		}
-	);
+	my $self    = shift;
+	my $filter  = LINQ::Util::Internal::assert_code( @_ );
+	my $stopped = 0;
+	my $started = 0;
+	my $iter    = $self->to_iterator;
+
+	require LINQ;
+	LINQ::Util::Internal::create_linq( sub {
+		SKIPPING: {
+			return LINQ::END() if $stopped;
+			my @got = $iter->();
+			if ( ! @got ) {
+				$stopped++;
+				redo SKIPPING;
+			}
+			return $got[0] if $started;
+			if ( $filter->( $_ = $got[0] ) ) {
+				redo SKIPPING;
+			}
+			++$started;
+			return $got[0];
+		};
+	} );
 } #/ sub skip_while
 
 sub concat {
-	my @collections = @_;
+	my @collections = map $_->to_iterator, @_;
 	my $idx = 0;
 
 	require LINQ;
-	require LINQ::Iterator;
-	'LINQ::Iterator'->new( sub {
-		local ( $@, $_ );
-		my $next;
+	LINQ::Util::Internal::create_linq( sub {
 		FIND_NEXT: {
 			return LINQ::END() if not @collections;
 
-			my $ok = eval { $next = $collections[0]->element_at( $idx ); 1 };
-			my $e  = $@;
-			if ( $ok ) {
-				++$idx;
-				return $next;
+			my @got = $collections[0]->();
+			if ( not @got ) {
+				shift @collections;
+				redo FIND_NEXT;
 			}
-			elsif ( defined $e and not $ok ) {
-				require Scalar::Util;
-				die( $e ) unless Scalar::Util::blessed( $e );
-				die( $e ) unless $e->isa( 'LINQ::Exception::NotFound' );
-				die( $e ) unless $e->collection == $collections[0];
-			}
-			shift @collections;
-			$idx = 0;
-			redo FIND_NEXT;
+
+			return $got[0];
 		};
 	} );
 }

diff --git a/t/21iter-take_while.t b/t/21iter-take_while.t
@@ -6,8 +6,6 @@
 
 Given an iterator LINQ, checks exceptions get rethrown correctly.
 
-Test fails on older Perls for... reasons(?) so we skip test on Perl < 5.16. 
-
 =head1 AUTHOR
 
 Toby Inkster E<lt>tobyink@cpan.orgE<gt>.
@@ -23,7 +21,7 @@ the same terms as the Perl 5 programming language system itself.
 
 BEGIN { $LINQ::FORCE_ITERATOR = 1 }
 
-use Test::Modern -requires => { 'perl' => '5.016' };
+use Test::Modern;
 use LINQ qw( LINQ );
 
 my $c1 = LINQ( sub { die "My error" } )->take_while( sub { 1 } );