OneTuple (empty) → 0.1.0

raw patch · 5 files changed

+153/−0 lines, 5 filesdep +basesetup-changed

Dependencies added: base

Files

Data/Tuple/OneTuple.hs +73/−0
FAQ +27/−0
LICENSE +34/−0
OneTuple.cabal +15/−0
Setup.hs +4/−0

+ Data/Tuple/OneTuple.hs view

@@ -0,0 +1,73 @@++-- |OneTuple fills the /tuple gap/ with a singleton tuple.+-- +-- OneTuple /does not support/ the usual parenthesized tuple syntax.+-- +-- OneTuple+--+--   * has the expected laziness properties+--+--   * can be pattern-matched+--+--   * ships with instances for several standard type classes,+--     including all those supported by H98-standard tuples+--+--   * requires no language extensions, except for hierarchical modules++module Data.Tuple.OneTuple (OneTuple(OneTuple), only) where++import Control.Applicative+import Control.Monad+import Data.Foldable+import Data.Ix+import Data.Monoid+import Data.Traversable++-- |OneTuple is the singleton tuple data type.+data OneTuple a+    = OneTuple a  -- ^ singleton tuple constructor+    deriving (Eq,Ord,Bounded,Show,Read)++-- |The 'only' function extracts the OneTuple's only member.+-- (Compare to 'fst' and 'snd'.)+only :: OneTuple a -- ^ takes a singleton tuple argument+     -> a          -- ^ returns the only element in the tuple+only (OneTuple x) = x++instance (Enum a) => Enum (OneTuple a) where+    succ = liftA succ+    pred = liftA pred+    toEnum = pure . toEnum+    fromEnum (OneTuple x) = fromEnum x++instance (Ix a) => Ix (OneTuple a) where+    range   (OneTuple x, OneTuple y) = map OneTuple (range (x,y))+    index   (OneTuple x, OneTuple y) (OneTuple z) = index   (x,y) z+    inRange (OneTuple x, OneTuple y) (OneTuple z) = inRange (x,y) z++instance Foldable OneTuple where+    fold (OneTuple m) = m+    foldMap f (OneTuple x) = f x+    foldr f b (OneTuple x) = f x b+    foldl f a (OneTuple x) = f a x+    foldr1 _f (OneTuple x) = x+    foldl1 _f (OneTuple x) = x++instance Traversable OneTuple++instance Functor OneTuple where+    fmap f (OneTuple x) = OneTuple (f x)++instance Applicative OneTuple where+    pure = return+    (<*>) = ap++instance Monad OneTuple where+    (OneTuple x) >>= f = f x+    return = OneTuple++instance (Monoid a) => Monoid (OneTuple a) where+    mempty = OneTuple mempty+    mappend (OneTuple x) (OneTuple y) = OneTuple (mappend x y)+    mconcat = Prelude.foldr1 mappend+

+ FAQ view

@@ -0,0 +1,27 @@++This is a list of Frequently Asked Questions about OneTuple, the+optional Haskell singleton tuple type.++Some of these are, of course, merely anticipated FAQs.++Q 1.  What's the point, if you can't support the same syntax as+      'normal' tuples?+A 1.  You can hack it up in TH if you want -- patches are welcome!+      Simplicity and (near) H98 compatibility were goals in building+      OneTuple.++Q 2.  Why define 'data OneTuple' instead of just a type alias?+A 2.  For laziness and pattern matching similar to other tuples.++Q 3.  Isn't this the same as <something> ?+A 3.  Could be, but this one's sold as a tuple!++Q 4.  Singleton tuples don't make sense!  They're isomorphic to their+      component type!+A 4.  Yes, that's true, up to laziness.++Q 5.  What's NST?+A 5.  "Need Singleton Tuple".  It's the class of problems that can't+      be solved without using a singleton tuple.  Also conveniently+      stands for "No Such Thing".+

+ LICENSE view

@@ -0,0 +1,34 @@++Copyright (c) 2008, John A. Dorsey.+All rights reserved.++Redistribution and use of this software in source and binary forms,+with or without modification, are permitted provided that the+following conditions are met:++* Redistributions of source code must retain the above+  copyright notice, this list of conditions and the+  following disclaimer.++* Redistributions in binary form must reproduce the above+  copyright notice, this list of conditions and the+  following disclaimer in the documentation and/or other+  materials provided with the distribution.++* Neither the name of John Dorsey nor the names of its+  contributors may be used to endorse or promote products+  derived from this software without specific prior+  written permission.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,+OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY+OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.+

+ OneTuple.cabal view

@@ -0,0 +1,15 @@+Name:            OneTuple+Version:         0.1.0+Synopsis:        OneTuple, the Singleton Tuple+Description:     OneTuple, the Singleton Tuple+Copyright:       (c) John Dorsey 2008+License:	 BSD3+License-file:    LICENSE+Author:          John Dorsey <haskell@colquitt.org>+Maintainer:      John Dorsey <haskell@colquitt.org>+Cabal-version:   > 1.4+Stability:       experimental+Build-type:      Simple+Build-depends:   base+Exposed-Modules: Data.Tuple.OneTuple+

+ Setup.hs view

@@ -0,0 +1,4 @@+ +import Distribution.Simple+main = defaultMain+