[Haskell-cafe] Lenses: Should I declare Getters?

Oliver Charles ollie at ocharles.org.uk
Tue Sep 10 17:06:44 CEST 2013

On 09/10/2013 06:31 AM, Charlie Paul wrote:
> I've been looking through Edward Kmett's lens library, and I'm a bit
> befuddled about Getters. In my own code, why would I want to have
> something be a Getter instead of a plain function? As far as I can see,
> a plain function is simpler to use, and can be converted to a Getter
> with "to" if we want to use it as a Fold. Is there a situation where
> writing a Getter is superior than writing a function, then lifting it as
> needed?

Generally, you don't provide 'Getter's because people can always lift a
function with "to" - as you said. This is mentioned in the lens FAQ at:


- ocharles

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