Hi all,
i'm having a bit of difficulty using GHCi to try out HXT.
i brought the Text.XML.HXT.Arrow module into scope using :m. Then i entered:
let contact = mkelem "stream:stream" [ sattr "xmlns:stream"
"http://etherx.jabber.org/streams";, sattr "xmlns" "jabber:client", sattr "to"
"livejournal.com" ] []
and got the error message:
<interactive>:1:14:
Ambiguous type variable `a' in the constraint:
`ArrowXml a' arising from use of `mkelem' at <interactive>:1:14-19
Probable fix: add a type signature that fixes these type variable(s)
The type signature of mkelem is
mkelem :: (ArrowXml a) =>
String -> [a n XmlTree] -> [a n XmlTree] -> a n XmlTree
So then i modified it to:
let contact = mkelem "stream:stream" [ sattr "xmlns:stream"
"http://etherx.jabber.org/streams";, sattr "xmlns" "jabber:client", sattr "to"
"livejournal.com" ] [] :: ArrowXml a => a XmlTree XmlTree
And got:
<interactive>:1:14:
Ambiguous type variable `a' in the constraint:
`ArrowXml a'
arising from instantiating a type signature at <interactive>:1:14-194
Probable fix: add a type signature that fixes these type variable(s)
i don't understand why i need to specify type signatures when they should
already be in scope? And if i /do/ need to specify the type signatures for
some reason, how do i do so in a manner that works?
Any help much appreciated!
Alexis.
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