Re: ordered string-list considered harmful, was Re: [PATCH v3] Allow aliases that include other aliases
- Date: Thu, 6 Sep 2018 23:32:41 -0700
- From: Jonathan Nieder <jrnieder@xxxxxxxxx>
- Subject: Re: ordered string-list considered harmful, was Re: [PATCH v3] Allow aliases that include other aliases
Jeff King wrote:
> I don't see any point in generating a sorted list and _then_ making an
> auxiliary hashmap. My idea was that if you're using a sorted string-list
> for lookup, then you can replace the whole thing with a hash (inserting
> as you go, rather than sorting at the end).
What if I'm sorting a string list in preparation for emitting a sorted
list, and I *also* want to perform lookups in that same list? In
> I think Stefan pointed out a "case 4" in the other part of the thread:
> ones where we really care not just about fast lookup, but actual
> iteration order.
I had assumed that that was the whole point of this data structure.
Anything else that is using it for lookups should indeed use a hash
map instead, and I can take my share of blame for missing this kind of
thing in review.
> I think I like the hashmap way, if the conversion isn't too painful.
If we don't have any callers that actually need the sort-and-lookup
thing, then yay, let's get rid of it. But I don't actually think of
this as the hashmap way. It's the get-rid-of-the-unneeded-feature
In other words, *regardless* of what else we should do, we should
update any callers that want a hashmap to use a hashmap. Please go
ahead, even if it doesn't let us simplify the string list API at all.