[Haskell-cafe] Rational and % operator remix

michael rice nowgate at yahoo.com
Sun Mar 29 16:38:13 EDT 2009

cf2 :: Rational -> [Int]
cf2 a = let ai = floor a          <-- Doesn't this make ai an Int?   -Michael
              if a == (toRational ai)
                then [ai]
                else ai : cf2 (1 / (a - ai))

--- On Sun, 3/29/09, Brandon S. Allbery KF8NH <allbery at ece.cmu.edu> wrote:

From: Brandon S. Allbery KF8NH <allbery at ece.cmu.edu>
Subject: Re: [Haskell-cafe] Rational and % operator remix
To: "michael rice" <nowgate at yahoo.com>
Cc: "Brandon S. Allbery KF8NH" <allbery at ece.cmu.edu>, "Lennart Augustsson" <lennart at augustsson.net>, haskell-cafe at haskell.org
Date: Sunday, March 29, 2009, 4:27 PM

On 2009 Mar 29, at 16:19, michael rice wrote:but I'm still at least one error short of a clean run

Main> :load cf.hs
ERROR "cf.hs":7 - Type error in application
*** Expression     : ai : cf2 (1 / (a - ai))
*** Term           : ai
*** Type           : Ratio Integer
*** Does not match : Int

Where did I go wrong or what did I leave out?

cf2 returns [Int], but you're using it as the tail of a list starting with ai, which is a Rational.  Need to decide which you actually want.  At a guess:
> cf2 a = let ai = floor a>             rai = toRational ai>          in>             if a == rai>             then [ai]>             else rai : cf2 (1 / (a - ai))
 -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.comsystem administrator [openafs,heimdal,too many hats] allbery at ece.cmu.eduelectrical and computer engineering, carnegie mellon university    KF8NH

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