[Haskell] Bugged fgl package?

Feedback & Bugs
#1

Hello. It seems that Codingame uses old version of fgl library. The following code works on my computer with fgl-5.5:

-- a graph with two nodes and string labels
let gr = mkGraph [(0, "zone 0 data"), (1, "zone 1 data")] [(0,1,())] :: Gr String ()

-- printing it
> prettyPrint gr
0:"zone 0 data"->[((),1)]
1:"zone 1 data"->[]

-- taking first node and putting it back again
> prettyPrint ((&) (fromJust $ fst $ match 0 gr) gr)
0:"zone 0 data"->[((),1)]
1:"zone 1 data"->[]
-- we've got the same graph, everything is ok

Almost same code on codingame is not:

let gr = mkGraph [(0, "zone 0 data"), (1, "zone 1 data")] [(0,1,())] :: Gr String ()
hPutStrLn stderr $ show $ gr --works
hPutStrLn stderr $ show $ ((&) (fromJust $ fst $ match 0 gr) gr) --not

0:“zone 0 data”->[((),1)]1:“zone 1 data”->[]Answer: Node Exception, Node: 0

It would be nice if you fix this, because without the ability to update graph nodes this library is basically useless.

Thanks in advance.

#2

@6yearold: we’ll check and update if needed but I am not sure we will be able to do it before the end of Platinum Rift.