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from dataclasses import dataclass
from mypy.nodes import FloatExpr
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
Don't hardcode math constants like pi, tau, or e, use the `math.pi`,
`math.tau`, or `math.e` constants respectively.
Bad:
```
def area(r: float) -> float:
return 3.1415 * r * r
```
Good:
```
import math
def area(r: float) -> float:
return math.pi * r * r
```
"""
name = "use-math-constant"
code = 152
categories = ("math", "readability")
CONSTANTS = {
"pi": "3.14",
"e": "2.71",
"tau": "6.28",
}
def check(node: FloatExpr, errors: list[Error]) -> None:
num = str(node.value)
if len(num) <= 3:
return
for name, value in CONSTANTS.items():
if num.startswith(value):
errors.append(ErrorInfo.from_node(node, f"Replace `{num}` with `math.{name}`"))
|
