quickson-0.3: Quick JSON extractions with Aeson

Safe HaskellNone




How to use this library

Quickson exports a function quickson which enables you to perform quick extractions of JSON data using Aeson.

Aeson's type machinery allows decoding of complex data structures using just the decode function, however, JSON object lookups cannot be encoded using the type system alone. Quickson helps by doing the lookups for you so that the type system can do the rest. For example, say you have a JSON document as such:

{ "name": "bob", "age": 25, "hobbies": [{"name": "Tennis"}] }

And you'd like to turn this into a `(String, Maybe Int, [String])` with minimal fuss:

>>> type Hobbyist = (String, Maybe Int, [String])
>>> let eitherResult = quickson "{name,age?,hobbies:[{name}]}" jsonDoc :: Either String Hobbyist
Right ("bob",Just 25,["Tennis"])

So the structure specification is just to remove the objects so that the type system can do the rest.


  • Top level objects must be [] or {}
  • Lookup: {key}
  • Optional lookup: {key?} (yielding Maybe a)
  • List: []

data Quickson Source #

Quickson intermediary representation


Ob [(Text, Bool, Quickson)] 
Li Quickson 

parseQuickson :: ByteString -> Either String Quickson Source #

Parse a quickson structure

quicksonExecute :: FromJSON a => Quickson -> Value -> Either String a Source #

Execute a quickson structure against a value

quickson :: FromJSON a => ByteString -> ByteString -> Either String a Source #

Perform a JSON extraction, returning either an error description or a parsed data structure