Data.Aeson.Utils

This module provides a few small functions to make working with aeson easier. Hopefully at some point they won't be needed anymore.

Documentation

module Data.Aeson

module Data.Aeson.Types

Parsing values

decodeV :: FromJSON a => ByteString -> Maybe a

Deserialize any JSON value. Allows atomic values on the top level

eitherDecodeV :: FromJSON a => ByteString -> Either String a

Like decodeV, but returns an error message when decoding fails.

Utilities

fromFloatDigits :: RealFloat a => a -> Scientific

Convert a RealFloat (like a Double or Float) into a Scientific number.

Note that this function uses floatToDigits to compute the digits and exponent of the RealFloat number. Be aware that the algorithm used in floatToDigits doesn't work as expected for some numbers, e.g. as the Double 1e23 is converted to 9.9999999999999991611392e22, and that value is shown as 9.999999999999999e22 rather than the shorter 1e23; the algorithm doesn't take the rounding direction for values exactly half-way between two adjacent representable values into account, so if you have a value with a short decimal representation exactly half-way between two adjacent representable values, like 5^23*2^e for e close to 23, the algorithm doesn't know in which direction the short decimal representation would be rounded and computes more digits

(.=?) :: ToJSON a => Text -> Maybe a -> Maybe Pair

Optionally create a Pair.

parseNumber :: Scientific -> Either Integer Double

Convert a Scientific into an Integer if it doesn't have decimal points, otherwise to a Double.