+ my $c = 1 - count $r;
+ return $r, ($l && $c) ? { 'list' => $c } : undef
+}
+
+sub pp_grepwhile {
+ my ($self, $op) = @_;
+
+ $op = $op->first;
+ return $self->inspect($op) if name($op) ne 'grepstart';
+ $op = $op->first->sibling;
+
+ my ($r2, $l2) = $self->inspect($op->sibling);
+ return $r2, $l2 if $r2 and zero $l2;
+ diag Dumper [ $r2, $l2 ] if $DEBUG;
+ my $c = count $l2; # First one to happen
+
+ my ($r1, $l1) = $self->inspect($op);
+ diag Dumper [ $r1, $l1 ] if $DEBUG;
+ return (add $r2, scale $c, $r1), undef if $r1 and zero $l1 and not zero $l2;
+ return { 'list' => 1 }, undef if list $l2;
+
+ $l2 = { $l2 => 1 } unless ref $l2;
+ my $r = add $r2, scale $c,
+ normalize
+ add map { power $r1, $_, $l2->{$_} } keys %$l2;
+ $c = 1 - count $r;
+ return $r, $c ? { ((zero $l2) ? 0 : 'list') => $c } : undef;
+}
+
+sub pp_mapwhile {
+ my ($self, $op) = @_;
+
+ $op = $op->first;
+ return $self->inspect($op) if name($op) ne 'mapstart';
+ $op = $op->first->sibling;
+
+ my ($r2, $l2) = $self->inspect($op->sibling);
+ return $r2, $l2 if $r2 and zero $l2;
+ my $c = count $l2; # First one to happen
+
+ my ($r1, $l1) = $self->inspect($op);
+ return (add $r2, scale $c, $r1), undef if $r1 and zero $l1 and not zero $l2;
+ diag Dumper [ [ $r1, $l1 ], [ $r2, $l2 ] ] if $DEBUG;
+
+ $l2 = { $l2 => 1 } unless ref $l2;
+ my $r = add $r2, scale $c,
+ normalize
+ add map { power $r1, $_, $l2->{$_} } keys %$l2;
+ $c = 1 - count $r;
+ my $l = scale $c, normalize add map { power $l1, $_, $l2->{$_} } keys %$l2;
+ return $r, $l;
+}