Jules Bean wrote:
Thomas Hartman wrote:
I found
http://haskell.cs.yale.edu/haskell-report/List.html
had many useful "one off" type list functions such as "subsequences"
and "permutations" which are nowhere to be found in hoogle, Data.List,
or the haskell hierarchical libs
Weird.
It's not very many. Other that those, I spotted: sums, products,
elemIndexBy, elemBy.
I have no idea why they were removed between that version of the report
and haskell98.
For the ones you mention:
- sums, products:
The names don't make it clear what they do, I could for instance
imagine sums being 'map sum'. And should it be a 'scanl' or 'scanr'?
- elemIndexBy, elemBy:
elemBy f x = any (f x)
elemIndexBy f xs x = findIndex (f x) xs
On the other hand, I would love to see "subsequences" and "permutations"
added to Data.List. In fact, I made a library proposal to make this
happen, hopefully they will be added to the standard library soon.
Twan
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