Couldn't we use \\ for multi-case lambdas with layout?
If not, these are my preferences in order (all are single argument versions):
1: Omission: "case of". There seems to be some support for this but it
was not included in the summary.
2: Omission with clarification: "\case of"
3: "\of" - but I
Thank you for your response Edward,
You write that it is usually only evaluated once, do you know the
circumstances under which it is evaluated more than once? I have some
examples of this but they are all very large.
The real issue I was having was actually not with a list but with a
memoised fu
Hi,
Is there a way to ensure that functions in a class instance are
treated as top level definitions and not re-evaluated?
For instance if I have this:
>>>
class C a where
list :: [a]
instance List a => List [a] where
list = permutations list
<<<
How can I ensure that list :: [[X]] is evalua
C enables SilentDefaultSuperInstances by default,
> as a pragmatic choice to avoid legacy issues, but not DefaultSuperInstances.
> If (only) SilentDefaultSuperInstances is enabled, I propose that Option 2 is
> used. It makes perfect sense to warn if you override a default instance,
>
can turn it off, and it's not fatal.
>
> Does anyone advocate something else?
>
> Simon
>
> | -Original Message-
> | From: glasgow-haskell-users-boun...@haskell.org
> [mailto:glasgow-haskell-users-
> | boun...@haskell.org] On Behalf Of Jonas Almström Dure
> The question then comes down to whether that warning should ever be
> strengthened to an error.
Indeed.
> I agree that such a scenario is possible. The present situation gives
> no choice but to do things badly, but things often get done badly the
> first time around anyway. Perhaps I'm just gr
Hi,
On 31 August 2011 12:22, Conor McBride wrote:
> I become perplexed very easily. I think we should warn whenever silent
> pre-emption (rather than explicit) hiding is used to suppress a default
> instance, because it is bad --- it makes the meaning of an instance
> declaration rather more cont
| > There seems to be a lot of support for Option 3... but what about
Option 2 (ie pre-empt but give a warning)?
I think option 2 sounds very good. Possibly with the exception of only
warning when the manual instance is in another module, since you will
never experience the "perplexity" described
Hi,
First of all, I love the idea of default superclass instances!
About the opt-out feature, the problem with option 3 is only present
if the superclass instance is defined in another module (you won't see
unexpected behavior from your own instances). One solution is to use
option 3 if the offen
Hi,
I have an alternative suggestion, please let me know what you think.
We introduce an alternative start tag i.e. a quote can start with [q|
or [q\| (or something similar). If [q| is used then the quoted text is
used verbatim and if the alternative start-tag is used then the escape
sequences su
Hi,
In ghci, if you change a module that exports a TH template it will not
recompile modules that use the template. Example:
-- In A.hs
{-#LANGUAGE TemplateHaskell#-}
module A where
import Language.Haskell.TH
a = [d|x = 5|]
-- in B.hs
{-#LANGUAGE TemplateHaskell#-}
import A
a
-- As expected in
Hi GHC users!
Does anyone know if an import that is only used by Template Haskell (i.e.
not in "actual" code) is reflected in the produced executable?
Example:
import LargeModule(thFunction)
$thfunction
...
Is LargeModule linked in the executable file? (Assume thFunction is not
referenced by
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