literalizer 2026.3.16.1

Convert JSON data structures to native language literal syntax.

literalizer

literalizer converts JSON data structures to native language literal syntax (Python, JavaScript, TypeScript, Go, Ruby, C#, C++, Java, Kotlin, Rust, Haskell, Swift, PHP).

• Installation

• Usage examples

• Use cases

• Full documentation

Installation

Requires Python 3.12+.

pip install literalizer

Usage examples

"""Examples of using literalizer."""

from literalizer import (
    JAVA,
    JAVASCRIPT,
    PYTHON,
    LanguageSpec,
    format_bytes_hex,
    format_date_iso,
    format_datetime_iso,
    literalize_json,
    literalize_yaml,
)

# Convert a JSON array to Java literal items
result = literalize_json(
    json_string='[true, null, "hi", [1, 2]]',
    language=JAVA,
    prefix="",
    wrap=False,
)
# result:
# true,
# null,
# "hi",
# {1, 2},

# Convert to JavaScript/TypeScript array
result = literalize_json(
    json_string='[true, null, "hi", [1, 2]]',
    language=JAVASCRIPT,
    prefix="    ",
    wrap=True,
)
# result:
# [
#     true,
#     null,
#     "hi",
#     [1, 2],
# ]

# Convert a JSON string to Python
result = literalize_json(
    json_string='[true, null, "hi", [1, 2]]',
    language=PYTHON,
    prefix="",
    wrap=True,
)
# result:
# (
#     True,
#     None,
#     "hi",
#     (1, 2),
# )

# Convert from a YAML string directly
result = literalize_yaml(
    yaml_string="- true\n- null\n- hi\n- [1, 2]",
    language=PYTHON,
    prefix="",
    wrap=True,
)
# result:
# (
#     True,
#     None,
#     "hi",
#     (1, 2),
# )

# Built-in languages: PYTHON, JAVASCRIPT, TYPESCRIPT, GO, RUBY,
#                      CSHARP, CPP, JAVA, KOTLIN, RUST, HASKELL, SWIFT, PHP


# Create a custom language:
def _omap_entry(key: str, value: str) -> str:
    """Format an ordered-map entry."""
    return f"{key}: {value}"


custom = LanguageSpec(
    null_literal="nil",
    true_literal="TRUE",
    false_literal="FALSE",
    collection_open="[",
    collection_close="]",
    dict_separator=": ",
    dict_open="{",
    dict_close="}",
    format_dict_entry=None,
    trailing_comma=True,
    single_element_trailing_comma=False,
    format_bytes=format_bytes_hex,
    format_date=format_date_iso,
    format_datetime=format_datetime_iso,
    empty_collection=None,
    empty_dict=None,
    set_open="[",
    set_close="]",
    empty_set=None,
    format_set_entry=None,
    comment_prefix="//",
    omap_open="{",
    omap_close="}",
    format_omap_entry=_omap_entry,
    multiline_close_indent="",
    skip_null_dict_values=False,
    format_variable_declaration=None,
)

Use cases

• Generate test fixtures from JSON samples.

• Convert API responses to language-native data structures for documentation.

• Create type-safe literal data from JSON config files.

Full documentation

See the full documentation for more information including how to contribute.