The closest thing to guards that'll work is multi-way-if (you'll have to
put "{-# LANGUAGE MultiWayIf #-}" at the top of your source file)
e.g.
buysell = if | oldbuysell ot == "buy" = Buy
| oldbuysell ot == "sell" = Sell
| otherwise = Unknown
but a 'case' is slightly shorter here:
buysell = case oldbuysell ot of
"buy" -> Buy
"sell" -> Sell
_ -> Unknown
Tom
On Mon, Apr 14, 2014 at 4:22 AM, Kim-Ee Yeoh
On Mon, Apr 14, 2014 at 1:03 PM, Dimitri DeFigueiredo < defigueiredo@ucdavis.edu> wrote:
oldbuysell :: String -- "buy", "sell" or ""
Why is this String when you've defined the perfectly cromulent BuyOrSell datatype?
How can you be sure there won't be some accidental buggy code that sets the field to "buyy"?
-- Kim-Ee
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