added experimental oterate() function with docs

README.md

@@ -9,3 +9,4 @@ Current version is broken with perl < 5.16 because
  or just *remove* `lines` from the perlude core (it is a very wrong place)
 * yada (`...`) was introduced in perl 5.14 AFAIK
 * investigate possible bug in range with 1 argument
+* missing tests for oterate

lib/Perlude.pm

@@ -18,15 +18,33 @@ our @EXPORT = qw<
     nth
     chunksOf
     as_open
+    oterate
 >; 
 
-# ABSTRACT: Shell and Powershell pipes, haskell keywords mixed with the awesomeness of perl. forget shell scrpting now! 
+# ABSTRACT: Shell and Powershell pipes, haskell keywords mixed with the awesomeness of perl. forget shell scripting now! 
 
 use Carp;
 
 our $VERSION   = '0.61';
 our $EXHAUSTED = sub {()};
 
+sub oterate {
+    my ($iter,$filter,$self) = @_;
+    my ( $i, @i ) = ref $iter   ? @$iter   : $iter  ;
+    my ( $f, @f)  = ref $filter ? @$filter : $filter;
+    my $exhausted = 0;
+    my @v;
+    sub {
+
+        return if $exhausted;
+
+        do { @v and return shift @v }
+           while (@v = $self->$i(@i));
+
+        $exhausted=1;
+        return;
+    }
+};
 
 sub _natural_from {
     my ($fn, $pos, $v) = @_;

lib/Perlude.pod

@@ -238,6 +238,51 @@ L<http://hackage.haskell.org/packages/archive/base/latest/doc/html/Prelude.html#
 
 =head2 generators
 
+=head3 oterate ($iter,$filter,$self) # EXPERIMENTAL
+
+it's B<Oterate> (like Object Iterate). the basic boring pattern is 
+
+    my $tap = TAP::Parser->new({qw( source test)});
+    while (my $e = $tap->next) {
+        if ($e->is_ok) { say $e->as_string }
+    }
+
+replacing it by perlude gives you power but the code
+still isn't pleasant to read.
+
+    now {say $_->as_string}
+        filter {$_->is_ok}
+        sub {
+            state $tap = TAP::Parser->new({qw( source test)});
+            $tap->next // ()
+        }
+
+Perlude + L<https://metacpan.org/pod/curry> does it better
+
+    now {say $_->as_string}
+        filter {$_->is_ok}
+        TAP::Parser
+        -> new({qw( source test)})
+        -> curry::next;
+
+oterate does the same, plus adds the filter into the generator
+
+    oterate qw(next is_ok)
+    , TAP::Parser->new({qw( source test)})
+
+using array ref, you can also add arguments to both the iterator and the
+filter:
+
+    oterate
+    , [qw( next file     )]
+    , [qw( is   readable )]
+    , Some->new
+
+is like
+
+    filter {$_->is('readable')} Some->new->curry::next('file')
+
+
 =head3 range $begin, [ $end, [ $step ] ]
 
 A range of numbers from $begin to $end (infinity if $end isn't set) $step by $step.