Brent Yorgey wrote:
Not really. You are welcome to look at the source of Data.List.Split.Internals yourself;
Fair enough, I will look at it.
Let me be clear---I am not against adding some splitting functions to Data.List, if consensus as to what these functions should be is reached.
Not to worry, this was clear to me. I am sorry if my thread obscured this.
If I were to write
organizeBy :: ([a] -> Bool) -> [a] -> [([a], [a])]
could you think of a specification such that this function would be a work horse in implementing Data.List.Split.Internals and Data.List.Split?
I could, but I think the result would be rather uglier and harder to understand than the current implementation.
I understand. I do not perceive that I have expressed very well the way that I am trying to conceptualise of this, but the observation of yours above makes me conclude that adding a few splitter functions to Data.List would just be arbitrary. (Alex already stated this point of view.)
Finally, this whole thread brings up the question in my mind about module design. As work is put into Data.List.Split, what is the guiding principle that prevents it from becoming Data.List.Extensions or to be a bit more direct, Data.List.TheFunctionsThatWereForgotten?
Are you serious?
Well, actually yes, I was serious, but see below.
It seems quite clear to me that Data.List.Split will *not* turn into that. For one thing, it contains only list-splitting functions; for another thing, I do not foresee putting that much more work into it.
Ok, I was on a tangent. Given this above, no, I was not serious.
A theoretical module which contains implementations/combinators for implementing every possible method of list-splitting known to man. This way no one has to argue about what the correct interface for split is, we can just have them all.
Is not this Data.List? In other words, what idea or theme does a new Haskell programmer use to decide to first look into Data.List as opposed to Data.List.Split and vice versa?
I was being sort of facetious in that quote. =)
Ok, once again, I was on a tangent and drifting off topic. In my defence, my parents-in-law were here for my Son's birthday which in Alsace means a lot of good food and wine which also means I should not write e-mails at night after such an event :). -- So, to conclude, when I first started using Haskell 98, at one point in time I was looking for some splitter idioms in the List module. The functions break and span were close, but not it. The functions
lines :: String -> [String] unlines :: [String] -> String
words :: String -> [String] unwords :: [String] -> String
seemed out of place compared to everything else in the List module just because of their type signature whereupon it seemed even more odd that I could not just split /etc/passwd or /etc/group on ':' with something directly suited to the task that was in the List module as an example. Thanks for the thread, - Marcus -- Marcus D. Gabriel, Ph.D. Saint Louis, FRANCE http://www.marcus.gabriel.name mailto:marcus@gabriel.name