Safe Haskell	Safe
Language	Haskell2010

Text.Read.Bounded

Description

Class for reading bounded values.

Synopsis

data BoundedRead a
- = NoRead
- | ExactRead a
- | ClampedRead a
class ReadBounded a where
- readBounded :: String -> BoundedRead a
readBoundedInteger :: (Bounded a, Read a, Integral a) => String -> BoundedRead a

Documentation

data BoundedRead a Source #

Information about a bounded read.

Constructors

NoRead	The read failed.
ExactRead a	The value was successfully read exactly, and did not have to be clamped to a narrower representation.
ClampedRead a	The value was successfully read, but had to be clamped to a narrower representation because its value was too wide.

Instances

Eq a => Eq (BoundedRead a) Source #
Instance details Defined in Text.Read.Bounded Methods (==) :: BoundedRead a -> BoundedRead a -> Bool # (/=) :: BoundedRead a -> BoundedRead a -> Bool #
Ord a => Ord (BoundedRead a) Source #
Instance details Defined in Text.Read.Bounded Methods compare :: BoundedRead a -> BoundedRead a -> Ordering # (<) :: BoundedRead a -> BoundedRead a -> Bool # (<=) :: BoundedRead a -> BoundedRead a -> Bool # (>) :: BoundedRead a -> BoundedRead a -> Bool # (>=) :: BoundedRead a -> BoundedRead a -> Bool # max :: BoundedRead a -> BoundedRead a -> BoundedRead a # min :: BoundedRead a -> BoundedRead a -> BoundedRead a #
Read a => Read (BoundedRead a) Source #
Instance details Defined in Text.Read.Bounded Methods readsPrec :: Int -> ReadS (BoundedRead a) # readList :: ReadS [BoundedRead a] # readPrec :: ReadPrec (BoundedRead a) # readListPrec :: ReadPrec [BoundedRead a] #
Show a => Show (BoundedRead a) Source #
Instance details Defined in Text.Read.Bounded Methods showsPrec :: Int -> BoundedRead a -> ShowS # show :: BoundedRead a -> String # showList :: [BoundedRead a] -> ShowS #

class ReadBounded a where Source #

Much like the Read class, but will return (possibly) clamped values.

Typical instances of this class will clamp against minBound and maxBound

This class is designed to avoid inconsistency problems such as the following:

>>> read "321" :: Word8
65
>>> read "4321" :: Word8
225
>>> read "-4" :: Word8
252

Using this class, the results are predictable and precise:

>>> readBounded "321" :: BoundedRead Word8
ClampedRead 255
>>> readBounded "4321" :: BoundedRead Word8
ClampedRead 255
>>> readBounded "-4" :: BoundedRead Word8
ClampedRead 0
>>> readBounded "255" :: BoundedRead Word8
ExactRead 255
>>> readBounded "6" :: BoundedRead Word8
ExactRead 6
>>> readBounded "xxx" :: BoundedRead Word8
NoRead

Methods

readBounded :: String -> BoundedRead a Source #

Instances

ReadBounded Int Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Int Source #
ReadBounded Int8 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Int8 Source #
ReadBounded Int16 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Int16 Source #
ReadBounded Int32 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Int32 Source #
ReadBounded Int64 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Int64 Source #
ReadBounded Integer Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Integer Source #
ReadBounded Word Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Word Source #
ReadBounded Word8 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Word8 Source #
ReadBounded Word16 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Word16 Source #
ReadBounded Word32 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Word32 Source #
ReadBounded Word64 Source #
Instance details Defined in Text.Read.Bounded Methods readBounded :: String -> BoundedRead Word64 Source #

readBoundedInteger :: (Bounded a, Read a, Integral a) => String -> BoundedRead a Source #

Reads a clamped value for any integer type with the given class constraints. Useful for implementing a ReadBounded instance or avoiding one.