diff --git a/LICENSE b/LICENSE --- a/LICENSE +++ b/LICENSE @@ -1,5 +1,5 @@ -Copyright 2012,2013,2014 Russell O'Connor -Copyright (c) 2014, michaelt +Copyright (c) 2012,2013,2014 Russell O'Connor +Copyright (c) 2015, michaelt All rights reserved. diff --git a/Lens/Simple.hs b/Lens/Simple.hs --- a/Lens/Simple.hs +++ b/Lens/Simple.hs @@ -1,54 +1,70 @@ -{-#LANGUAGE CPP #-} +{-#LANGUAGE CPP, RankNTypes #-} module Lens.Simple ( - -- * Stock Lenses - _1, _2 - , chosen - , ix - , at, intAt - , contains, intContains - - -- * Stock Traversals - , both + -- * Fundamental lens combinators (@view\/(^.)@, @set\/(.~)@, @over\/(%~)@) + view + , set + , over + + -- * Characteristic lenses (@_1@, @_2@) and traversals (@_Left@, @_Right@ etc.) + , _1 + , _2 , _Left, _Right , _Just, _Nothing - , ignored + , both - -- * Basic lens combinators - , to, view, (^.) - , folding, views, (^..), (^?) - , toListOf, allOf, anyOf, firstOf, lastOf, sumOf, productOf - , lengthOf, nullOf - , backwards - , over, (%~), set, (.~) - , (&) - , (??) - -- * Pseudo-imperatives - , (+~), (*~), (-~), (//~), (&&~), (||~), (<>~) - - -- * State related combinators + -- * Lens (etc.) formers + , lens + , iso + , setting + , to + + -- * Basic state related combinators: @zoom@, @use@, @assign\/(.=)@ etc. , zoom , use, uses + , assign + + -- * Commonly used operators: particularly @view\/(^.)@, @set\/(.~)@, @over\/(%~)@ + , (^.) + , (%~) + , (.~) + , (&) + , (??) + , (?~) + , (^..) + , (^?) + + -- * Convenient state-related operators , (%=) - , assign, (.=) + , (.=) , (%%=) , (<~) - -- * Compound state assignments - , (+=), (-=), (*=) - , (//=) - , (&&=), (||=) - , (<>=) + -- * Pseudo-imperatives + , (+~), (*~), (-~), (//~), (&&~), (||~), (<>~) - -- * Stock Semantic Editor Combinators + + -- * Corresponding state-related imperatives + , (+=), (-=), (*=), (//=), (&&=), (||=), (<>=) + + -- * Stock semantic editor combinators (setters) , mapped - -- * Lens formers - , lens - , iso - , setting + -- * More stock lenses + , chosen + , ix + , at, intAt + , contains, intContains - -- * Combining Combinators + -- * More stock traversals + , ignored + + + -- * Other combinators + , folding, views + , toListOf, allOf, anyOf, firstOf, lastOf, sumOf, productOf + , lengthOf, nullOf + , backwards , choosing , alongside , beside @@ -58,15 +74,18 @@ , makeTraversals , makeLensesBy , makeLensesFor - -- * Types + -- * Types + , Lens, Lens' + , Traversal, Traversal' + , Getter, Getter' + , Setter, Setter' , LensLike, LensLike' , FoldLike, FoldLike' - , ASetter, ASetter' , Phantom - , Constant, Identity + , Constant (..), Identity (..) , AlongsideLeft, AlongsideRight - , Zooming + , Zooming -- * Re-exports , Monoid(..),(<>) @@ -76,11 +95,13 @@ import Lens.Family2.State.Strict import Lens.Family2.TH (makeLenses, makeTraversals, makeLensesBy, makeLensesFor) import Data.Monoid +import Data.Functor.Identity +import Data.Functor.Constant #if MIN_VERSION_base(4,8,0) import Data.Function ((&)) -import Lens.Family hiding (Fold,(&)) +import Lens.Family2 hiding ((&)) #else -import Lens.Family hiding (Fold) +import Lens.Family2 #endif infixl 1 ?? @@ -92,3 +113,6 @@ (??) :: Functor f => f (a -> b) -> a -> f b ff ?? a = fmap ($ a) ff {-# INLINE (??) #-} +-- +(?~) :: Setter a a' b (Maybe b') -> b' -> a -> a' +l ?~ b = set l (Just b) diff --git a/lens-simple.cabal b/lens-simple.cabal --- a/lens-simple.cabal +++ b/lens-simple.cabal @@ -1,5 +1,5 @@ name: lens-simple -version: 0.1.0.3 +version: 0.1.0.4 synopsis: simplified import of elementary lens-family combinators description: This module, , @@ -10,29 +10,49 @@ other TH incantations from Dan Burton's associated . The idea is just to make a sort of low-powered, minimal-dependency @lens-family@ equivalent of + the 800 lb gorilla of lens library imports: . > import Control.Lens . - namely: + to wit, the elegant and spritely: . > import Lens.Simple . Check it out, it's even one character shorter! . - As an illustration of the power of even these elementary combinators, note that the + If you are unfamiliar with the use of what O'Connor calls van Laarhoven + lenses, you might take a + look at the excellent + for the + library. All of the tutorial material will compile if you replace + @import Control.Lens@ with the suave @import Lens.Simple@. + The error messages you get might be a little less opaque. But + the point is basically academic, of course: you have already weighed down your + sandbox with the @lens@ library by installing @wreq@ and if you get + any deeper into @wreq@ you will need it. + . + As another illustration of the simplicity of the + fundamental van Laarhoven lens combinators, note that the gloss - from the @lens@ library requires only this abbreviating change of imports. - If you care to make that program more complicated, you might at some point need + from the @lens@ library examples directory requires only this + abbreviating change of imports. + If you care to make that program more complicated, + you might at some point need the unfathomably more sophisticated material in @Control.Lens@. - Because @lens-family@ accords as - far as possible, with @Control.Lens@, within its more limited sphere, - a change of imports will often be all that is necessary to begin using them. + Within its more limited sphere, @lens-family@ accords as + far as possible with @lens@, so this switch + will often be all that is necessary to begin using them. . - It is rarely necessary to exceed the materials exported here when using - the lenses and quasi-lenses exported by e.g. + This module was originally intended to simplify the use of packages that + follow the original promise of the van Laarhoven lenses. Correct practice is + to export lenses without depending on a lens-library, where possible; + in basic cases these use just familiar @Prelude@ types. + Examples of best practices in this respect are - or . It is simplify - the use of such that this module was originally intended. + and . + Because of the heavily monadic character of those libraries, the + extra material in @Control.Lens@ is rarely of use anyway; one sticks largely + to @view\/(^.)@, @set\/(.~)@, @over\/(%~)@ and @zoom@. . Note that many of the other lenses and combinators are a bit more specialized than their @Control.Lens@ equivalents: @@ -47,7 +67,7 @@ license-file: LICENSE author: michaelt maintainer: what_is_it_to_do_anything@yahoo.com -copyright: Copyright (C) 2012,2013,2014 Russell O'Connor, 2014 michaelt +copyright: 2012, 2013, 2014 Russell O'Connor; 2015 Michael Thompson category: Lenses build-type: Simple extra-source-files: README.md @@ -59,6 +79,7 @@ library exposed-modules: Lens.Simple build-depends: base >= 4 && < 5 + , transformers < 4.3 , lens-family == 1.2.* , lens-family-core == 1.2.* , lens-family-th == 0.4.*