Re: [Haskell-cafe] Question on a common pattern

Hi, Donn Cave wrote:

...

someIO>>= f where f Opt1 = ...

I like this ... or, I would like it, if I could make it work!

I get "The last statement in a 'do' construct must be an expression",

Where-clauses can only be used on equations, not on expressions or statements, so you would need to float the where clause outwards: foo = do someIO >>= f where f = ... Or you can use let-in-expressions or let-statements to bind local values (or functions) in do-notation: do let f = ... result <- someIO >>= f or do result <- let f = ... in someIO >>= Op1 = .. HTH, Tillmann