factor some code-based stream types out into classes

[catagits/HTML-Zoom.git] / lib / HTML / Zoom / MappedStream.pm

diff --git a/lib/HTML/Zoom/MappedStream.pm b/lib/HTML/Zoom/MappedStream.pm
new file mode 100644 (file)
index 0000000..09ef6be
--- /dev/null
+++ b/lib/HTML/Zoom/MappedStream.pm
@@ -0,0 +1,29 @@
+package HTML::Zoom::MappedStream;
+
+use strict;
+use warnings FATAL => 'all';
+use base qw(HTML::Zoom::StreamBase);
+
+sub new {
+  my ($class, $args) = @_;
+  bless({
+    _source => $args->{source}, _mapper => $args->{mapper},
+    _zconfig => $args->{zconfig}
+  }, $class);
+}
+
+sub next {
+  return unless (my $self = shift)->{_source};
+  # If we were aiming for a "true" perl-like map then we should
+  # elegantly handle the case where the map function returns 0 events
+  # and the case where it returns >1 - if you're reading this comment
+  # because you wanted it to do that, now would be the time to fix it :)
+  if (my ($next) = $self->{_source}->next) {
+    local $_ = $next;
+    return $self->{_mapper}->($next);
+  }
+  delete $self->{_source};
+  return
+}
+
+1;