#amjson

#Features

• Complete JSON Support: Parses all JSON value types:
  • null
  • Booleans (true, false)
  • Numbers (integers, floats, scientific notation)
  • Strings (with escape sequences and Unicode escapes)
  • Arrays
  • Objects

• Error Handling: Provides detailed error messages with position information
• Standards Compliant: Follows the JSON specification
• Zero Dependencies: Uses only MoonBit standard library

#Usage

#Basic Example

///|
test "basic usage" {
  let json = "{\"name\": \"Alice\", \"age\": 30}"
  let result = @tonyfettes/amjson.parse(json)
  match result {
    Object(map) => {
      inspect(map.get("name"), content="Some(String(\"Alice\"))")
      inspect(map.get("age"), content="Some(Number(30))")
    }
    _ => fail("Expected Object")
  }
}

#Parsing Different Value Types

///|
test "parse different types" {
  // Null
  let null_val = @tonyfettes/amjson.parse("null")
  inspect(null_val, content="Null")

  // Boolean
  let bool_val = @tonyfettes/amjson.parse("true")
  inspect(bool_val, content="Bool(true)")

  // Number
  let num_val = @tonyfettes/amjson.parse("42.5")
  inspect(num_val, content="Number(42.5)")

  // String
  let str_val = @tonyfettes/amjson.parse("\"hello\"")
  inspect(str_val, content="String(\"hello\")")

  // Array
  let arr_val = @tonyfettes/amjson.parse("[1, 2, 3]")
  inspect(arr_val, content="Array([Number(1), Number(2), Number(3)])")
}

#Error Handling

///|
test "error handling" {
  let invalid_json = "{invalid}"
  let result = try! @tonyfettes/amjson.parse(invalid_json)
  match result {
    Err(UnexpectedChar(_pos, ch)) => inspect(ch, content="i")
    _ => fail("Expected parse error")
  }
}

#Complex Nested Structures

///|
test "nested structures" {
  let json =
    #|{
    #|  "users": [
    #|    {"name": "Bob", "score": 95.5},
    #|    {"name": "Carol", "score": 87.0}
    #|  ],
    #|  "count": 2
    #|}
    #|
  let result = @tonyfettes/amjson.parse(json)
  match result {
    Object(map) => {
      match map.get("users") {
        Some(Array(users)) => inspect(users.length(), content="2")
        _ => fail("Expected users array")
      }
      inspect(map.get("count"), content="Some(Number(2))")
    }
    _ => fail("Expected Object")
  }
}

#API

#parse(input: String) -> JsonValue raise ParseError

• input: A string containing valid JSON

• A JsonValue representing the parsed JSON

• ParseError with position information if parsing fails

#JsonValue Type

///|
pub enum JsonValue {
  Null
  Bool(Bool)
  Number(Double)
  String(String)
  Array(Array[JsonValue])
  Object(Map[String, JsonValue])
}

#ParseError Type

///|
pub(all) suberror ParseError {
  UnexpectedChar(Position, Char)
  UnexpectedEof(Position)
  InvalidNumber(Position, String)
  InvalidEscape(Position)
  InvalidUnicodeEscape(Position)
}

#String Escape Sequences

• \" - Double quote
• \\ - Backslash
• \/ - Forward slash
• \b - Backspace
• \f - Form feed
• \n - Newline
• \r - Carriage return
• \t - Tab
• \uXXXX - Unicode escape (4 hex digits)

#Number Format

• Integers: 42, -123
• Floats: 3.14, -2.5
• Scientific notation: 1e10, 1.5e-3

#License