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Today's Topics:
1. Re: combine expressions in do block (Brent Yorgey)
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Message: 1
Date: Wed, 8 Jan 2014 15:31:05 -0500
From: Brent Yorgey <[email protected]>
To: [email protected]
Subject: Re: [Haskell-beginners] combine expressions in do block
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii
On Wed, Jan 08, 2014 at 09:21:59AM +0100, Daniel Trstenjak wrote:
>
> Hi Renah,
>
> On Wed, Jan 08, 2014 at 10:09:18AM +0200, Renah Scarowsky wrote:
> > How can I combine these two cases together (or otherwise simplify the code)?
>
> I don't know if I'm understanding you correctly, but something like this?
>
> f a = do
> case g a of
> Nothing -> return ()
> Just b -> do
> h a (field1 b) (field2 b)
> i a (j a) (field1 b) (field2 b)
To take this a step further, if 'field1' and 'field2' are projections,
then you might be able to replace them with pattern-matching as well:
f a = do
case g a of
Nothing -> return ()
Just (Constructor f1 f2) -> do
h a f1 f2
i a (j a) f1 f2
I know this is just a made-up example and not real code, but figured
it was worth mentioning anyway.
-Brent
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