Tool Introduction
The "JSON to Haskell Class" tool aims to help Haskell developers quickly and conveniently convert JSON strings into corresponding Haskell data type (data/newtype) definitions. When you need to process JSON data from APIs or other external sources, this tool can automatically generate Haskell-compliant code, greatly simplifying the effort of manually writing data models and improving development efficiency. The input is a "JSON string", and the output is "converted Haskell data type" code.
How to Use
- Input JSON Data: Paste or manually enter the valid JSON data you need to convert into the "JSON String" input box on the left.
- View Conversion Results: The tool will display the generated Haskell data type code in real-time in the "Converted Class" output box on the right, based on the input JSON structure.
- Copy and Use: Simply copy the generated Haskell code from the output box and integrate it into your Haskell project.
Input Parameter Format and Requirements:
The "JSON String" field requires a standard, structurally valid JSON format string. Whether it's a single JSON object, a JSON array, or contains nested structures, this tool can parse it.
Output Result Format:
The "Converted Class" will display Haskell-compliant module definitions, typically includingdata declarations, field accessors, and necessaryderiving clauses (such asShow,Generic,FromJSON,ToJSON, etc.), to enable seamless integration with Haskell's Aeson library for JSON serialization and deserialization.
Frequently Asked Questions
- Q: What input formats are supported?
- A: This tool only supports standard JSON strings as input. Please ensure your input is a structurally complete and valid JSON format.
- Q: What is the format of the output?
- A: The output is data type (
data ornewtype) definition code compliant with Haskell syntax, usually including thederiving (Show, Generic, FromJSON, ToJSON) clause, making it easy for Haskell projects to use directly.
- Q: Can it handle complex nested JSON and arrays?
- A: Yes. The tool has recursive parsing capabilities and can correctly handle multi-level nested JSON objects and arrays, generating corresponding Haskell data types for them.
- Q: What are the field naming conversion rules?
- A: The tool intelligently converts JSON field names (e.g.,
camelCase orsnake_case) into Haskell-idiomatic field names (e.g.,personName,addressStreet), usually by prefixing the field name with the data type name to avoid conflicts.
Notes
- Ensure JSON Validity: The input JSON string must be legally formatted and valid; any syntax errors may lead to conversion failure. It is recommended to use a JSON validation tool before conversion.
- Type Inference: The tool will do its best to infer the most suitable Haskell type based on JSON values (e.g., strings converted to
String, integers toInt, floating-point numbers toDouble, booleans toBool). However, for certain numeric types (such as requiringInteger instead ofInt), you may need to manually adjust the generated code according to actual business requirements.
- Haskell Modules and Imports: The generated code will typically include a
module MyTypes where declaration andimport statements; please adjust them appropriately according to your project structure.
- Aeson Integration: By default,
FromJSON andToJSON instances compatible with the Haskell Aeson library will be generated, facilitating JSON serialization and deserialization operations.
