[Haskell-cafe] Beginners arrow question

Paul Johnson paul at cogito.org.uk
Sat Apr 5 14:05:41 EDT 2008

I'm using arrows for the first time, with HXT.  I think I'm getting the 
hang of it, but one problem has me stumped.  I have a function 
"lookupFormatter" which takes a string and returns an arrow, and I want 
to use that arrow.  Something like this:

myProblem :: (ArrowXml a) -> a XmlTree String
myProblem = proc xml do
   name <- getAttrValue "name" -< xml
   fmt <- arr lookupFormatter -< name
   fmt -< xml

But I can't figure out how to do it.  I get "fmt: not in scope".

Can anyone help?



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