An IsString (NonEmpty Char) instance

Ivan Lazar Miljenovic ivan.miljenovic at
Sun Sep 3 22:25:04 UTC 2017

On 4 September 2017 at 08:17, Henning Thielemann
<lemming at> wrote:
> On Mon, 4 Sep 2017, Ivan Lazar Miljenovic wrote:
>> It's backwards-incompatible, but my preference - especially when you
>> consider the libraries that parse the String - is to have fromString return
>> Maybe.
> An expression that is undefined because of "" would become an expression
> that is undefined because of Nothing, right? I do not see a benefit.

Sorry, yes, I was thinking that GHC could determine that the result
was Nothing and throw a type-checking failure, but that doesn't work.

Ivan Lazar Miljenovic
Ivan.Miljenovic at

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