mirror of
https://github.com/correl/typesafe-monads.git
synced 2024-11-14 19:19:32 +00:00
57 lines
1.5 KiB
Python
57 lines
1.5 KiB
Python
from __future__ import annotations
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from monads.result import Result, Ok, Err, safe
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def test_value() -> None:
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result: Result[int, str] = Ok(5)
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assert 5 == result.withDefault(0)
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def test_error() -> None:
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result: Result[int, str] = Err("oops")
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assert 0 == result.withDefault(0)
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def test_map() -> None:
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result: Result[int, str] = Ok(5)
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mapped: Result[str, str] = result.map(str)
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assert "5" == mapped.withDefault("0")
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def test_map_infix() -> None:
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result: Result[int, str] = Ok(5)
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mapped: Result[str, str] = result * str
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assert "5" == mapped.withDefault("0")
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def test_bind() -> None:
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result: Result[int, str] = Ok(5)
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incremented: Result[int, str] = result.bind(lambda x: Ok(x + 1))
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assert 6 == incremented.withDefault(0)
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def test_bind_infix() -> None:
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result: Result[int, str] = Ok(5)
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incremented: Result[int, str] = result >> (lambda x: Ok(x + 1))
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assert 6 == incremented.withDefault(0)
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def test_pipeline() -> None:
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class Frobnicator(object):
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@classmethod
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def create(cls, config: dict) -> Result[Frobnicator, str]:
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return Ok(cls())
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def dostuff(self) -> Result[list, str]:
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return Ok(["a", "b", "c", "d"])
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def load_config() -> Result[dict, str]:
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return Ok({"foo": "bar"})
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result: Result[int, str] = (
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load_config()
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>> Frobnicator.create
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>> Frobnicator.dostuff
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>> (lambda res: Ok(len(res)))
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)
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assert 4 == result.withDefault(0)
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