Proposal: strictify foldl'

[Henning Thielemann]

On Mon, 3 Nov 2014, David Feuer wrote:

> Proposal: make foldl' unconditionally strict in the initial accumulator 
> value, both in GHC.List and in (the default definition in) 
> Data.Foldable, and make foldr' in Data.Foldable unconditionally strict 
> in the initial value of its accumulator.

I am worried about the general move from foldl to foldl', because foldl' 
is still not strict enough. E.g. if the accumulator is a list, only the 
leading (:) is evaluated. I would prefer a strict foldl provided by the 
deepseq package and deprecate foldl' in favor of deepseq:foldl. This new 
foldl could immediately implement the unconditional strictness for the 
initial accumulator value.