KotlinJSONParser

KotlinJSONParser is a simple and lightweight JSON parser written in Kotlin. It allows you to easily parse JSON strings into Kotlin objects. This is mostly a toy project and with that less useful for normal usage. If you want to use a JSON parser, you should consider JSON parsers like Jackson or Gson.

This JSON parser is fully JSON RFC compliant.

Features

• Lightweight and easy to use
• Built with Kotlin
• Simple API
• No dependencies

Parser Flow

---
title: Parser Flow
---

graph LR;
    S("Source (String)")-->L;
    O("Source (Other)")-.- Convert -.->S;
    O-.->LT;

    subgraph LI[Lexer Interface]
    L(String Lexer);
    LT("(Source) Lexer");
    end

    LI-->P(Parser);
    P-->D(Data in Memory)
    
    style Convert fill:#e1e1e1,stroke:none
    style LT stroke:#808080,stroke-dasharray: 5 5
    style O stroke:#808080,stroke-dasharray: 5 5

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Note

Everything that is currently dashed is not being completely implemented and needs some extra work.

Getting Started

Prerequisites

• Kotlin
• Gradle

Usage

Here's a simple example of how to use KotlinJSONParser:

val jsonString = """{"name": "John", "age": 30}"""
val json = jsonParse(jsonString)

println(json["name"]) // Output: John
println(json["age"])  // Output: 30

If a different input type is being wanted a Lexer that implements JSONLexer can be provided:

val jsonString = """{"name": "John", "age": 30}"""
val json = jsonParse(StringJSONLexer(jsonString))
//                   ^ Implements the JSONLexer interface

println(json["name"]) // Output: John
println(json["age"])  // Output: 30

The JSONLexer interface requires two methods:

1. getNext() -> Returns the next token from the input.

   If the input has ended it will provide an EOF Token.

2. getPosition(position, length): -> Returns some specific position data for error handling.

The jsonParse function

The jsonParse function returns these Datatypes:

• Boolean
• String
• (Null)
• BigDecimal
• List
• Map

More information

If you want to know more about the project and how it works, check out the wiki.

Or otherwise just check out the source code. 😄

License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.