Is this a bug?

[charles.huthwaite@aonconsulting.co.uk]

infixr 5 ~=
a ~= b = a-b<h && b-a<h
      where h = 0.000001

zero f = until goodEnough improve 1.0
      where improve b = b - f b / diff f b
            goodEnough b = (f b ~= 0.0)

gives

ERROR "train2c.hs":7 - Syntax error in input (unexpected `=')

Is this a bug or have I coded it wrong?

Thanks

C

PS: Taken from page 39 of Functional Programming by Jeroen Fokker 1995


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