Good Haskell Style
seth at cql.com
Wed Aug 1 11:33:06 EDT 2007
I've been using Haskell daily for a long time, and I didn't know about that
underscore convention. I knew about _ being an unspecified dummy variable,
but I didn't know you are allowed to follow it with a meaningful name.
Guess I have some reading to do. :)
From: libraries-bounces at haskell.org [mailto:libraries-bounces at haskell.org]
On Behalf Of Chris Kuklewicz
Sent: Wednesday, August 01, 2007 11:31 AM
To: Philippa Cowderoy
Cc: libraries at haskell.org; Simon Marlow
Subject: Re: Good Haskell Style
Philippa Cowderoy wrote:
> On Wed, 1 Aug 2007, Simon Marlow wrote:
>> I'm rather attached to the convention I use, which is
>> - CamelCase for exported identifiers
>> - underscores otherwise
>> Yes I'm aware that a single-word identifier is the same in both
>> it's not perfect.
> How about _nonexportedIdentifier or something similar?
Leading underscores are used in pattern matches to indicate to GHC that
names like '_foo' should not cause a warning to be printed. Otherwise the
warning is turned off by using just '_' but that erases the readability of
using an actual name.
take _  =  -- no warning
take n  =  -- warning that n is unused
take _n  =  -- no warning
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