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JSON

stdlib/json.kod parses and emits JSON.

Quick example

import "json"

let v: json.Value = json.parse("[1, 2, 3]")
// v is Array([Number(1), Number(2), Number(3)])

let s: str = json.emit(v)
// s is "[1,2,3]"

The Value type

type Value = enum {
    Null
    Bool(value: bool)
    Number(value: int64)        // int64 only — floats not supported
    Str(value: str)
    Array(items: [Value])
    Object(keys: [str], values: [Value])
}

Object entries are stored as parallel arrays (keys[i] ↔ values[i]) rather than a separate Entry struct, so the type stays single-recursive.

Accessors

Free functions (Kod doesn't yet support methods on enums) that return T? so callers can chain via let .Some(v) = ... else:

Function Returns
get(v: Value, key: str) -> Value Object lookup. Returns Null if the key is missing or v isn't an Object.
as_str(v: Value) -> str? Unwrap to a string, none if not Str.
as_int(v: Value) -> int64? Unwrap to an integer, none if not Number.
as_bool(v: Value) -> bool? Unwrap to a bool, none if not Bool. 
let .Some(method) = json.as_str(json.get(req, key: "method")) else { return }
let .Some(id) = json.as_int(json.get(req, key: "id")) else { return }

Limitations

  • Numbers are int64 only.
  • String escapes: \n \t \r \" \\ \/. No \uXXXX.
  • Strict JSON: no trailing commas, no comments.
  • Parse failure currently panics rather than returning an error type.