JSON

General concepts

Phonometrica values can be converted to and from JSON (JavaScript Object Notation), a lightweight declarative format which is often used to store data. See http://www.json.org.

The mapping between JSON and Phonometrica values is the natural one: a JSON object maps to a Table (with string keys), an array to a List, and a number to an Integer when it has no fraction or exponent (and fits), or a Float otherwise. true, false and null map to the corresponding Phonometrica values.

Parsing JSON never evaluates code, so it is a safe way to load data from an untrusted source. To load a JSON file, combine from_json() with read_file:

# var data = from_json(read_file("/path/to/data.json"))

Functions

to_json(value as Object)

Converts value to a string according to the JSON specification, in compact form. Since a Table is unordered, the order of the keys in the output is unspecified. A value that has no JSON representation (such as a Sound, or a non-finite number) raises an error.

var o = { "name": "John", "pi": 3.14 }

var s = to_json(o)
print(s) # prints e.g. '{"name":"John", "pi":3.14}'

---

to_json(value as Object, indent as Integer)

Converts value to a JSON string, pretty-printed with indent spaces per nesting level.

print(to_json([1, 2], 4))

This prints:

[
    1,
    2
]

---

from_json(str as String)

Parses the string str as a JSON document and returns the corresponding value. An invalid document raises an error indicating the position of the problem.

var s = '{"name": "John", "pi": 3.14}'
var o = from_json(s)
print("The value of pi is {o.pi}")