parallel: :::: now does nesting/product/cartesian/multiply (--xapply missing)

src/parallel

@@ -3905,6 +3905,7 @@ sub new {
 
 sub get {
     my $self = shift;
+return    $self->nest_get();
     if(@{$self->{'unget'}}) {
 	return shift @{$self->{'unget'}};
     }
@@ -3964,6 +3965,93 @@ sub get {
     }
 }
 
+sub nest_get {
+    my $self = shift;
+    if(@{$self->{'unget'}}) {
+	return shift @{$self->{'unget'}};
+    }
+    my @record = ();
+    my $prepend = undef;
+    my $empty = 1;
+    my $no_of_inputs = $#{$self->{'fhs'}} + 1;
+    if(not @::arg_matrix) {
+	# Initialize @::arg_matrix with one arg from each file
+	# read one line from each file
+	my @first_arg_set;
+	for (my $fhno = 0; $fhno < $no_of_inputs ; $fhno++) {
+	    my $fh = $self->{'fhs'}[$fhno];
+	    my $arg = <$fh>;
+	    # Remove delimiter
+	    $arg =~ s:$/$::;
+	    $::arg_matrix[$fhno][0]=Arg->new($arg);
+	    push @first_arg_set, $::arg_matrix[$fhno][0];
+	}
+	$self->unget([@first_arg_set]);
+    }
+    my @fh = @{$self->{'fhs'}};
+    for (my $fhno = 0; $fhno < $no_of_inputs; $fhno++) {
+	if(eof($fh[$fhno])) {
+	    next;
+	} else {
+	    # read one
+	    my $f = $fh[$fhno];
+	    my $arg = <$f>;
+	    # Remove delimiter
+	    $arg =~ s:$/$::;
+	    my $len = $#{$::arg_matrix[$fhno]}+1;
+	    $::arg_matrix[$fhno][$len]=Arg->new($arg);
+	    # make all new combinations
+	    my @combarg = ();
+	    for (my $fhn = 0; $fhn < $no_of_inputs; $fhn++) {
+		push @combarg, [0, $#{$::arg_matrix[$fhn]}];
+	    }
+	    $combarg[$fhno] = [$len,$len]; # Find only combinations with this new entry
+	    my @combinations = expand_combinations(@combarg);
+	    # map combinations
+	    # [ 1, 3, 7], [ 2, 4, 1 ]
+	    # =>
+	    # [ m[0][1], m[1][3], m[3][7]], [ m[0][2], m[1][4], m[2][1] ]
+	    my @mapped;
+	    for my $c (@combinations) {
+		my @a;
+		for my $n (0 .. $no_of_inputs - 1 ) {
+		    push @a,  $::arg_matrix[$n][$$c[$n]];
+		}
+		push @mapped, [@a];
+	    }
+	    # unget the mapped
+	    push @{$self->{'unget'}}, @mapped;
+	    # get the first
+	    return shift @{$self->{'unget'}};
+	}
+    }
+    # all are eof; return undef
+    return undef;
+}
+
+sub expand_combinations {
+    # Input:
+    #   ([xmin,xmax], [ymin,ymax], ...)
+    # Returns ([x,y,...],[x,y,...]) 
+    # where xmin <= x <= xmax and ymin <= y <= ymax
+    my $minmax_ref = shift;
+    my $xmin = $$minmax_ref[0];
+    my $xmax = $$minmax_ref[1];
+    my @p;
+    if(@_) {
+	# If there are more columns: Compute those recursively
+	my @rest = expand_combinations(@_);
+	for(my $x = $xmin; $x <= $xmax; $x++) {
+	    push @p, map { [$x, @$_] } @rest;
+	}
+    } else {
+	for(my $x = $xmin; $x <= $xmax; $x++) {
+	    push @p, [$x];
+	}	    
+    }
+    return @p;
+}
+
 sub unget {
     my $self = shift;
     ::debug("MultifileQueue-unget '@_'\n");