Compatibility shims for converting data-lens code to lens
There are several issues that are not addressed by switching to this package. The primary one is lens composition - with data-lens it is necessary to import (.) from Control.Category, while lens uses the regular (.) operator from Prelude. Furthermore, the order of the lens composition is reversed. For these reasons, if any amount of composition is done I recommend the following procedure:
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Create a module Compose which imports Control.Category (.) and declares (.-.) = flip (.). Then replace all imports of Control.Category((.)) with imports of Compose((.-.)). This lets us locate all the lens compositions. Replace uses of (.) to compose lenses with uses of (.-.) until everything builds.
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Change the declaration of (.-.) to flip (.). Swap all the lens compositions so everything builds again.
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Replace the data-lens dependency with lens and lens-compat, change the declaration of .-. to the prelude version of (.).
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Expand the lens-compat functions inline and remove the lens-compat dependency.