diff --git a/Data/String/Conv.hs b/Data/String/Conv.hs new file mode 100644 --- /dev/null +++ b/Data/String/Conv.hs @@ -0,0 +1,118 @@ +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE MultiParamTypeClasses #-} + +module Data.String.Conv + ( StringConv (..) + , toS + , toSL + , convS + , convSL + , Leniency (..) + ) where + +------------------------------------------------------------------------------ +import Data.ByteString.Char8 as B +import Data.ByteString.Lazy.Char8 as LB +import Data.Text as T +import Data.Text.Encoding as T +import Data.Text.Encoding.Error as T +import Data.Text.Lazy as LT +import Data.Text.Lazy.Encoding as LT +------------------------------------------------------------------------------ + + +------------------------------------------------------------------------------ +-- | Data type representing the two leniency modes defining how decoding +-- failure is handled. +data Leniency = Lenient | Strict + deriving (Eq,Show,Read,Ord,Enum,Bounded) + + +------------------------------------------------------------------------------ +-- | A type class to standardize string conversions. With this type class you +-- only need to remember one function for converting between any two string +-- variants. This package includes support for String, ByteString, and Text +-- as well as the Lazy and Strict variants where necessary. +-- +-- This type class lets you control how conversion should behave when failure +-- is possible. Strict mode will cause an exception to be thrown when +-- decoding fails. Lenient mode will attempt to recover, inserting a +-- replacement character for invalid bytes. +-- +-- StringConv's `toS` function is most useful when you have a fully defined +-- string conversion with a fixed (non-polymorphic) input and output type. Of +-- course you can still use it when you don't have a fixed type. In that case +-- you might need to specify a type class constraint such as @StringConv +-- s String@. +class StringConv a b where + strConv :: Leniency -> a -> b + + +------------------------------------------------------------------------------ +-- | Universal string conversion function for strict decoding. +toS :: StringConv a b => a -> b +toS = strConv Strict + + +------------------------------------------------------------------------------ +-- | Universal string conversion function for lenient decoding. +toSL :: StringConv a b => a -> b +toSL = strConv Lenient + + +instance StringConv String String where strConv _ = id +instance StringConv String B.ByteString where strConv _ = B.pack +instance StringConv String LB.ByteString where strConv _ = LB.pack +instance StringConv String T.Text where strConv _ = T.pack +instance StringConv String LT.Text where strConv _ = LT.pack + +instance StringConv B.ByteString String where strConv _ = B.unpack +instance StringConv B.ByteString B.ByteString where strConv _ = id +instance StringConv B.ByteString LB.ByteString where strConv _ = LB.fromChunks . return +instance StringConv B.ByteString T.Text where strConv = decodeUtf8T +instance StringConv B.ByteString LT.Text where strConv l = strConv l . LB.fromChunks . return + +instance StringConv LB.ByteString String where strConv _ = LB.unpack +instance StringConv LB.ByteString B.ByteString where strConv _ = B.concat . LB.toChunks +instance StringConv LB.ByteString LB.ByteString where strConv _ = id +instance StringConv LB.ByteString T.Text where strConv l = decodeUtf8T l . strConv l +instance StringConv LB.ByteString LT.Text where strConv = decodeUtf8LT + +instance StringConv T.Text String where strConv _ = T.unpack +instance StringConv T.Text B.ByteString where strConv _ = T.encodeUtf8 +instance StringConv T.Text LB.ByteString where strConv l = strConv l . T.encodeUtf8 +instance StringConv T.Text LT.Text where strConv _ = LT.fromStrict +instance StringConv T.Text T.Text where strConv _ = id + +instance StringConv LT.Text String where strConv _ = LT.unpack +instance StringConv LT.Text T.Text where strConv _ = LT.toStrict +instance StringConv LT.Text LT.Text where strConv _ = id +instance StringConv LT.Text LB.ByteString where strConv _ = LT.encodeUtf8 +instance StringConv LT.Text B.ByteString where strConv l = strConv l . LT.encodeUtf8 + + +------------------------------------------------------------------------------ +-- | Convenience helper for dispatching based on leniency. +decodeUtf8T :: Leniency -> B.ByteString -> T.Text +decodeUtf8T Lenient = T.decodeUtf8With T.lenientDecode +decodeUtf8T Strict = T.decodeUtf8With T.lenientDecode + + +------------------------------------------------------------------------------ +-- | Convenience helper for dispatching based on leniency. +decodeUtf8LT :: Leniency -> LB.ByteString -> LT.Text +decodeUtf8LT Lenient = LT.decodeUtf8With T.lenientDecode +decodeUtf8LT Strict = LT.decodeUtf8With T.lenientDecode + + +------------------------------------------------------------------------------ +-- | A lens for 'toS' to make it slightly more convenient in some scenarios. +convS :: (StringConv a b, StringConv b a, Functor f) => (b -> f b) -> a -> f a +convS f a = fmap toS (f (toS a)) + + +------------------------------------------------------------------------------ +-- | A lens for 'toSL' to make it slightly more convenient in some scenarios. +convSL :: (StringConv a b, StringConv b a, Functor f) => (b -> f b) -> a -> f a +convSL f a = fmap toSL (f (toSL a)) + diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,30 @@ +Copyright (c) 2012, Ozgun Ataman + +All rights reserved. + +Redistribution and use 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 Ozgun Ataman nor the names of other + 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. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/string-conv.cabal b/string-conv.cabal new file mode 100644 --- /dev/null +++ b/string-conv.cabal @@ -0,0 +1,19 @@ +name: string-conv +version: 0.1 +synopsis: Standardized conversion between string types +description: Avoids the need to remember many different functions + for converting string types. Just use one universal + function toS for all monomorphic string conversions. +license: BSD3 +license-file: LICENSE +author: Ozgun Ataman +maintainer: ozgun.ataman@soostone.com +copyright: Soostone Inc, 2012-2015 +category: Data, String, Text +build-type: Simple +cabal-version: >=1.8 + +library + exposed-modules: Data.String.Conv + build-depends: base >= 4 && < 5, bytestring, text + ghc-options: -Wall -O2