Other functions (des, dropge, drople, limit, nv) can also benefit from scalar promotion. But since they are not reduction functions we'll need another way to do the tag matching. They may come in a later PR. At least we get forecastlr and percentile now.

drop__ could add a fair amount of power I think, something like:

$series = q("...")
$limit = last(q("..."))
$filteredSeries = dropge($series, percentille($series, .95))
$daysLeft = forecastlr($filteredSeries, $limit) / d("1d")  

Unless there is another way to do this...

Yes, they will happen. There's just no obvious common way to do them all now, since they don't have the same function signature.

Ok, now does the drop functions. My previous note is somewhat wrong. NV and limit should always remain scalars. Des could use this, but in reality that doesn't really make sense.

docs need to be updated to reflect the drop funcs

Updated with dropg, dropl, and docs.

Will fix #1064

Updated with better tests - now combined with the existing expr tests, it just knows about types now.