json

The json module provides JSON parsing, construction, and traversal. Requires import json.

Function Reference

Parsing and Serialization

Function	Signature	Description
parse	(String) -> Result[Value, String]	Parse JSON string
stringify	(Value) -> String	Convert to compact JSON string
stringify_pretty	(Value) -> String	Convert to pretty-printed JSON

Value Construction

Function	Signature	Description
from_string	(String) -> Value	Create string value
from_int	(Int) -> Value	Create integer value
from_float	(Float) -> Value	Create float value
from_bool	(Bool) -> Value	Create boolean value
null	() -> Value	Create null value
array	(List[Value]) -> Value	Create array value
object	(List[(String, Value)]) -> Value	Create object from key-value pairs

Key-Based Access

Function	Signature	Description
get	(Value, String) -> Option[Value]	Get nested value by key
get_string	(Value, String) -> Option[String]	Get string by key
get_int	(Value, String) -> Option[Int]	Get integer by key
get_float	(Value, String) -> Option[Float]	Get float by key
get_bool	(Value, String) -> Option[Bool]	Get boolean by key
get_array	(Value, String) -> Option[List[Value]]	Get array by key
keys	(Value) -> List[String]	Get all object keys

Value Extraction (keyless)

Function	Signature	Description
as_string	(Value) -> Option[String]	Extract string from value
as_int	(Value) -> Option[Int]	Extract integer from value
as_float	(Value) -> Option[Float]	Extract float from value
as_bool	(Value) -> Option[Bool]	Extract boolean from value
as_array	(Value) -> Option[List[Value]]	Extract array from value

Path API

Function	Signature	Description
root	() -> JsonPath	Create root path
field	(JsonPath, String) -> JsonPath	Extend path with field
index	(JsonPath, Int) -> JsonPath	Extend path with array index
get_path	(Value, JsonPath) -> Option[Value]	Get value at path
set_path	(Value, JsonPath, Value) -> Result[Value, String]	Set value at path
remove_path	(Value, JsonPath) -> Value	Remove value at path

Examples

import json

// Parse JSON
let data = json.parse("{\"name\": \"Alice\", \"age\": 30}")

// Access fields
match data {
  ok(j) => {
    let name = json.get_string(j, "name")  // => some("Alice")
    let age = json.get_int(j, "age")       // => some(30)
  },
  err(e) => println("parse error: " + e),
}

// Build JSON
let obj = json.object([
  ("name", json.from_string("Bob")),
  ("age", json.from_int(25)),
  ("scores", json.array([json.from_int(90), json.from_int(85)])),
])
let text = json.stringify_pretty(obj)

// Path-based access
let path = json.field(json.root(), "scores") |> json.index(_, 0)
let first_score = json.get_path(obj, path)  // => some(Value)