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 code that conforms to Haskell syntax, greatly simplifying the effort of manually writing data models and improving development efficiency. The input is a "JSON string", and the output is the "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: Directly 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 module definitions that conform to Haskell syntax, typically including data declarations, field accessors, and necessary deriving clauses (such as Show, 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 complete and valid JSON format.
- Q: What is the format of the output result?
- A: The output result is data type (
data or newtype) definition code that conforms to Haskell syntax, usually including the deriving (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 (such as
camelCase or snake_case) into Haskell-style field names (such as 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 to check before conversion.
- Type Inference: The tool will try its best to infer the most suitable Haskell type based on the JSON value (for example: strings are converted to
String, integers to Int, floating-point numbers to Double, booleans to Bool). However, for certain numeric types (such as needing Integer instead of Int), you may need to manually adjust the generated code according to actual business requirements.
- Haskell Modules and Imports: The generated code will usually include a
module MyTypes where declaration and import statements. Please make appropriate adjustments according to your project structure.
- Aeson Integration: By default,
FromJSON and ToJSON instances compatible with the Haskell Aeson library will be generated, facilitating JSON serialization and deserialization operations.
