Syntax & Grammar

This document defines the syntax and grammar rules for the TON file format.

Document Structure

// Optional header
#@ tonVersion = '1', @schemaFile = 'schema.ton'

// Root object (required)
{(className)
    // Properties
    property1 = value1,
    property2 = value2,

    // Child objects
    {(childClass)
        childProperty = value
    }
}

// Optional schema definitions
#! {(className)
    /property1 = string(required),
    /property2 = int(min(0))
}

Object Syntax

Objects are the fundamental structure in TON:

// Untyped object
{
    property = value
}

// Typed object
{(typeName)
    property = value
}

// Nested objects
{(parent)
    property = value,

    {(child)
        childProperty = value
    }
}

Property Rules

• Properties must appear before child objects
• Property names can be quoted or unquoted
• Values follow type-specific quoting rules
• Properties are separated by commas (trailing comma not allowed)

Array Syntax

// Simple array
[1, 2, 3]

// Mixed types
[1, "text", true, null]

// Nested arrays
[[1, 2], [3, 4]]

// Array of objects
[
    {(item) id = 1, name = "First"},
    {(item) id = 2, name = "Second"}
]

Type Hints

Optional prefixes to indicate expected types:

{
    stringValue = $"explicitly a string",
    numberValue = %42,
    guidValue = &550e8400-e29b-41d4-a716-446655440000,
    arrayValue = ^[1, 2, 3]
}

Grammar Rules (EBNF)

document        = [header] object [schemas]
header          = "#@" property-list
object          = "{" [class-type] [property-list] [object-list] "}"
class-type      = "(" identifier ")"
property-list   = property ("," property)*
property        = property-name "=" value
property-name   = identifier | string | number | "@" identifier
value           = string | number | boolean | null | undefined |
                  guid | date | enum | array | object
array           = "[" [value-list] "]"
value-list      = value ("," value)*
schemas         = schema+
schema          = "#!" (object-schema | enum-schema)