Safe Haskell	Safe-Inferred
Language	Haskell2010

LiBro.Data.SafeText

Contents

Definition of unsafe
A thin Text wrapper with smart data constructor
Safety checks
Explicit value creation
Other useful stuff

Description

Thin wrapper around Text, but without unsafe characters.

Synopsis

unsafeChars :: [Char]
data SafeText
getText :: SafeText -> Text
isSafeChar :: Char -> Bool
isSafeText :: Text -> Bool
isSafeString :: String -> Bool
safePackText :: Text -> Maybe SafeText
safePack :: String -> Maybe SafeText
safeModify :: (Text -> Text) -> SafeText -> Maybe SafeText
safeTextParser :: ReadS SafeText

Definition of unsafe

unsafeChars :: [Char] Source #

A list of all characters considered unsafe in our setting: '\NUL' and '\r'.

A thin `Text` wrapper with smart data constructor

SafeText is only a thin newtype wrapper around Text. To ensure that its characters are safe, the standard data constructor is hidden from exports.

How to create `SafeText` values?

Use safePack or safePackText to create Just SafeText values (or Nothing if the given text or string was unsafe).
Use SafeText's Read instance together with read or readMaybe.
Use SafeText's IsString instance together with the OverloadedStrings extension to create SafeText directly from string literals: "Hello, world" :: SafeText

Can `SafeText` be used exactly like `Text`?

No. There are very useful instances: Arbitrary for property tests with Test.QuickCheck, ToJSON and FromJSON for JSON stuff with Data.Aeson and ToField and FromField for CSV stuff with Data.Csv (Cassava).

Also, there's safeModify that allows Text modifying functions to be applied inside a SafeText. But it seems to be a bit overkill to export everything Data.Text has to offer.

data SafeText Source #

A simple newtype wrapper around Text, but ensures the absence of unsafe characters.

Instances

Instances details

Arbitrary SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods arbitrary :: Gen SafeText # shrink :: SafeText -> [SafeText] #
FromJSON SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods parseJSON :: Value -> Parser SafeText # parseJSONList :: Value -> Parser [SafeText] # omittedField :: Maybe SafeText #
ToJSON SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods toJSON :: SafeText -> Value # toEncoding :: SafeText -> Encoding # toJSONList :: [SafeText] -> Value # toEncodingList :: [SafeText] -> Encoding # omitField :: SafeText -> Bool #
IsString SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods fromString :: String -> SafeText #
Read SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods readsPrec :: Int -> ReadS SafeText # readList :: ReadS [SafeText] # readPrec :: ReadPrec SafeText # readListPrec :: ReadPrec [SafeText] #
Show SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods showsPrec :: Int -> SafeText -> ShowS # show :: SafeText -> String # showList :: [SafeText] -> ShowS #
FromField SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods parseField :: Field -> Parser SafeText #
ToField SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods toField :: SafeText -> Field #
Eq SafeText Source #
Instance details Defined in LiBro.Data.SafeText Methods (==) :: SafeText -> SafeText -> Bool # (/=) :: SafeText -> SafeText -> Bool #