type-yaml

Describes a yaml schema using Python types.

Simple Python types such as list[str] or dict[int, list[str]] that allow yaml to verify that the type fits and parse values based on it.

Requirements

• Python 3.8+
• PyYAML

Install

pip install type-yaml

Features:

• int
• float
• str
• bool
• list / typing.List
• dict / typing.Dict
• set / typing.Set
• tuple / typing.Tuple
• dataclass
  • default values and default-factory
  • special notation in yaml with metadata
• operator |/ typing.Union
• typing.Any
• lazy evaluation by string representation of type

Examples

from dataclasses import dataclass

from type_yaml import load


@dataclass
class Point:
    x: int
    y: int


print(load(list[Point], open("points.yaml")))
# >>> [Point(x=1, y=2), Point(x=3, y=4)]

# points.yaml
-
  x: 1
  y: 2
-
  x: 3
  y: 4

Usage

Functions such as load, loads, dump, and dumps can be imported from type_yaml. The details of each are as follows.

• load(type, stream, **kwargs)
  • Load a yaml file and parse it into a Python object.
  • type is a type that can be parsed by type_yaml.
  • stream is a text stream. e.g. open("file.yaml")
  • options
    • loader: yaml loader of PyYAML. default: yaml.SafeLoader
    • true_strings: list of strings that are parsed as True. default: ("true", "yes", "on", "1")
    • false_strings: list of strings that are parsed as False. default: ("false", "no", "off", "0")
    • type_name_map, globalns, localns: a dictionary or namespace of variable names is given to allow interpretation of the string representation of the type
• loads(type, string, **kwargs)
  • Load a yaml string and parse it into a Python object.
  • type is a type that can be parsed by type_yaml.
  • string is a yaml string.
  • options is same as load
• dump(value, stream, **kwargs)
  • Dump a Python object to a yaml file.
  • value is a Python object that can be parsed by type_yaml.
  • stream is a text stream. e.g. open("file.yaml")
  • options
    • dumper: yaml dumper of PyYAML. default: `type_yaml.yaml_interpreter.RealYamlDumper
• dumps(value, **kwargs)
  • Dump a Python object to a yaml string.
  • value is a Python object that can be parsed by type_yaml.
  • options is same as dump

Other

The license is the MIT License.

If you have any bugs, mistakes, feature suggestions, etc., issues and pull requests are welcome.