Other Special Characters

Special characters are used in conjunction with structural characters and literals to provide additional functionality or context within an Internet Object document. These characters have specific semantic meanings and modify the behavior of schemas, values, or parsing.

Special Character Set

Symbol	Name	Unicode	Context	Application
@	At Sign	U+0040	Variable	When prefixed to a key name, declares a variable reference
$	Dollar Sign	U+0024	Schema	When prefixed to a key name, declares a schema reference
?	Question Mark	U+003F	Schema	Shortcut for declaring optional member when suffixed to the key name in object schema
*	Asterisk	U+002A	Schema	Shortcut for declaring nullable member when suffixed to the key name in object schema. Also used to make schema accept undeclared variables
-	Hyphen / Minus	U+002D	Numeric	Represents negative value
+	Plus	U+002B	Numeric	Represents positive value

Usage Examples

Variable References and Schema Definitions

# Variable declarations
~ @r: red
~ @g: green
~ @b: blue

# Schema definitions using variables
~ $color: {string, choices: [@r, @g, @b]}
~ $schema: {
    name: string,
    email: email,
    joiningDt: date,
    color: $color
}

---
# Data using variable references
~ John Doe, '[email protected]', d'2020-01-01', @r

Schema Modifiers

# Optional and nullable field declarations
~ $user: {
    name: string,          # Required field
    email?: string,        # Optional field (may be omitted)
    avatar*: string,       # Nullable field (may be null)
    metadata*?: object     # Optional and nullable field
}

# Schema with undeclared variables acceptance
~ $flexible: {
    id: string,
    name: string,
    *                      # Accept additional undeclared fields
}

Numeric Signs

# Positive and negative numbers
temperature: +23.5         # Explicit positive
balance: -150.75          # Negative value
elevation: +8848          # Positive integer
debt: -5000               # Negative integer

Character Rules

• Context Sensitive: Characters have different meanings based on position and context

• Variable Prefixes: @ prefixes variable declarations and references

• Schema Prefixes: $ prefixes schema definitions and references

• Schema Suffixes: ? and * must be suffixed to field names in schema definitions

• Numeric Prefixes: + and - prefix numeric values to indicate sign

• Case Sensitive: All special characters are case-sensitive

• Reserved Usage: These characters are reserved for their specific functions

See Also

• Schema Definition - Detailed schema syntax and modifiers

• Number Values - Numeric value formatting and signs

• Structural Elements - Overview of all structural characters