Stream Insertion Operator

DDL provides a non-member stream insertion operator (operator<<) for printing ddl::value instances.

It supports all stored types, including nested arrays and objects.

Signature

std::ostream& operator<<(std::ostream& os, const value& v);

Parameters

Parameter	Description
os	Output stream to write to
v	DDL value to print

Returns

Returns a reference to the output stream, allowing chained stream operations.

Basic Usage

ddl::value data = 42;

std::cout << data << '\n';

Output:

42

Printing Arrays

ddl::value data = ddl::array{10, "Hello", true};

std::cout << data << '\n';

Output:

[
  10,
  Hello,
  true
]

Printing Objects

ddl::value data = ddl::object{
    {"name", "Alice"},
    {"age", 20}
};

std::cout << data << '\n';

Possible output:

{
  "age": 20,
  "name": Alice
}

Object property order is unspecified because DDL uses std::unordered_map.

Nested Structures

The operator recursively prints nested arrays and objects.

ddl::value data = ddl::object{
    {"name", "Alice"},
    {"skills", ddl::array{"C++", "Python"}}
};

std::cout << data << '\n';

Possible output:

{
  "skills": [
    C++,
    Python
  ],
  "name": Alice
}

Formatting

• Arrays and objects are formatted across multiple lines.
• Indentation uses two spaces per nesting level.
• Object keys are enclosed in double quotes.
• String values are printed without surrounding quotes.
• Empty arrays and objects are printed as [] and {}.
• Commas separate elements and properties, except after the last entry.