How to use XML to Haskell
- Paste a representative XML sample, ideally one with all the optional fields filled in.
- Set the name of the root type, and decide whether you want helper code as well or types only.
- Copy the generated Haskell code into your project.
About XML to Haskell
Writing model classes by hand for a big XML payload is dull, and it is where typos creep in. Paste a sample here and the generator works out the structure: which fields exist, which are objects, which are arrays and what type each value has. The output is record types with Aeson ToJSON and FromJSON instances.
XML is first converted to JSON the same way as in our XML to JSON tool: attributes get an @_ prefix and text content next to attributes is called #text. The Haskell types are generated from that result. Record fields get a prefix based on the type name, since Haskell does not allow two records in a module to share field names.
Using the generated code
Use decode from Data.Aeson, for example decode text :: Maybe Root.
Optional fields use the Maybe type.