How to implement Data.Map.insertList*?

[Daan Leijen]

Mirko Rahn wrote:

> These terms are hard to compare but a plot shows that insertList_foldl 
> should be faster than insertList_union.
> 
> But a testprogram shows that insertList_union is faster (and needs less 
> memory) whatever the sizes of n and m are.
> 
> So my questions are:
> 
> Why are the insertList* functions missing?

Just my laziness :)  Maybe someone can add them to the libraries?

> How would the library implementors implement insertList* and why?

I think I would use the "union" version as it is the simplest.
However, since the "foldl'" version seems faster, maybe one should
use that anyway. (Be careful though -- the union on IntMap's is
very fast -- it'll be hard to beat that even using foldl').

-- Daan.

> 
> thanks,
>