⚠️ Warning: This is a draft ⚠️
This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.
== The alternative Haskell solution needs attention ==
Unfortunately, the alternative Haskell solution, given by @Hout doesn't show the strength of Haskell. The alternative solution is ''very'' inefficient in case of big lists, due to a pattern
list ++ [element]. It ruins the effect of
It is possible to make this solution better by using ''difference lists'' with O(1)
snoc operator, but then it would require
toList . map toList instead of
reverse . map reverse as postprocessing. Another workaround would be to replace
: and perform reversion, but in this case the alternative solution will become just a paraphrase of a DFT solution with less modular logic.
After all, it is a sort of parsing problem, so the most natural solution would use some parsing technique (DFT, for example). I would be happy to see an alternative solution using any of parsing libraries, or conduits/pipes so that it could handle real-world text-based cases and demonstrate everyday practice.
I recommend to remove the solution.
: If you are not replacing the solution, please do not remove it. It's ok to document issues, but if it's really that much of a problem to come up with a better solution, an existing solution which meets the task requirements should almost always be considered adequate. --[[User:Rdm|Rdm]] ([[User talk:Rdm|talk]]) 02:40, 12 January 2017 (UTC)
: I have itemized solutions and added conduit-based solution. However, I don't see the reason to leave the inefficient and non-idiomatic variant. --[[User:Samsergey|Samsergey]] ([[User talk:Samsergey|talk]]) 03:39, 12 January 2017 (UTC)
: Thanks, your point about efficiency at scale is interesting and well taken. This task doesn't specify performance at scale, and I think it can be useful to also show the 'simplest' (or most naive :-) single fold solution, but I appreciate your having documented the issue. Very happy to remove for the moment and experiment. [[User:Hout|Hout]] ([[User talk:Hout|talk]]) 09:47, 12 January 2017 (UTC) :: Have now experimented, and agree with [[User:Samsergey|Samsergey]] :-) Let's remove it – once you make it more efficient at scale, it converges on the first solution, and needs the double reverse. Useful exercise for me – many thanks for your response ! [[User:Hout|Hout]] ([[User talk:Hout|talk]]) 11:29, 12 January 2017 (UTC) ::: On second thoughts, I notice that it appears, (tested with a 180k string), to be fractionally/trivially faster than the original DFA draft, so perhaps worth keeping, at least for the moment, for comparison/discussion [[User:Hout|Hout]] ([[User talk:Hout|talk]]) 14:22, 12 January 2017 (UTC)
:::: Let a hundred flowers blossom :) We like Haskell for expressiveness, flexibility and freedom to be either experimentators or nudniks which it offers. ::::: Thank you for your helpful thoughts, invariably excellent code, and even forbearance with nudniks :-) [[User:Hout|Hout]] ([[User talk:Hout|talk]]) 20:03, 12 January 2017 (UTC) ::::: (Of course, thinking back to an earlier life only 1hr behind Kamchatka, I do remember that Mao's patience with the blooming of 100 flowers was not to prove inexhaustible... :-) [[User:Hout|Hout]] ([[User talk:Hout|talk]]) 20:12, 12 January 2017 (UTC)