Hi Roman, fellow Haskellers, On 04/11/2014 05:35, Roman Cheplyaka wrote: Sounds interesting. Can you show (and include in the README) some examples of recognized json inputs and code generated for them? There are rather extensive examples provides as unit tests in the source code repository, which I do not distribute with the package, since they may be covered by copyright of whatever APIs they were produced with (like Twitter, YouTube, Jenkins etc.). Thanks for pointing out that there should be some examples provided along the package! The most simple example: { "colorsArray":[{ "colorName":"red", "hexValue":"#f00" }, { "colorName":"green", "hexValue":"#0f0" }, { "colorName":"blue", "hexValue":"#00f" } ] } It will produce the module with the following datatypes and TH calls for JSON parser derivations: data ColorsArray = ColorsArray { colorsArrayHexValue :: Text, colorsArrayColorName :: Text } deriving (Show,Eq) data TopLevel = TopLevel { topLevelColorsArray :: ColorsArray } deriving (Show,Eq) Note that attribute names match the names of JSON dictionary keys. Another example with ambiguous types: { "parameter":[{ "parameterName":"apiVersion", "parameterValue":1 }, { "parameterName":"failOnWarnings", "parameterValue":false }, { "parameterName":"caller", "parameterValue":"site API" }] } It will produce quite intuitive result (plus extra parentheses, and class derivations): data Parameter = Parameter { parameterParameterValue :: Either Bool (Either Int Text), parameterParameterName :: Text } data TopLevel = TopLevel { topLevelParameter :: Parameter } I will add these examples to the README. For real world use cases you might look at the current unit test directory. All of .json files there generate the correct parsers: https://github.com/mgajda/json-autotype/tree/master/test -- Best regards Michal On 03/11/14 18:59, Michal J Gajda wrote: Dear Fellow Haskellers, I've just published a beta version of a tool facilitating generation of Haskell type declarations from example JSON documents. It is supposed to simplify implementing large JSON-based interfaces, without necessity of writing any boilerplate code. USAGE: ====== After installing with `cabal install json-autotype`, you might generate stub code for the parser: $ json-autotype input.json -o MyFormat.hs Then you might test the parser by running it on an input file: $ runghc MyFormat.hs input.json If everything is correct, then feel free to inspect the data structure generated automatically for you! The goal of this program is to make it easy for users of big JSON APIs to generate entries from example data. Occasionally you might find a valid JSON for which `json-autotype` doesn't generate a correct parser. You may either edit the resulting file _and_ send it to the author as a test case for future release. HOW IT WORKS: ============== The program uses union type unification to trim output declarations. The types of same attribute tag and similar attribute set, are automatically unified using recognition by attribute set matching. (This option can be optionally turned off, or a set of unified types may be given explicitly.) Either alternatives is used to assure that all JSON inputs seen in example input file are handled correctly. Details on official releases are on Hackage [1] 1. https://hackage.haskell.org/package/json-autotype Patches and suggestions are most welcome. _______________________________________________ Haskell-Cafe mailing listHaskell-Cafe@haskell.orghttp://www.haskell.org/mailman/listinfo/haskell-cafe