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|
from dataclasses import dataclass
from mypy.nodes import (
ArgKind,
Block,
ComparisonExpr,
FuncItem,
LambdaExpr,
NameExpr,
OpExpr,
ReturnStmt,
UnaryExpr,
)
from refurb.checks.common import _stringify
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
Don't write lambdas/functions to wrap builtin operators, use the `operator`
module instead:
Bad:
```
from functools import reduce
nums = [1, 2, 3]
print(reduce(lambda x, y: x + y, nums)) # 6
```
Good:
```
from functools import reduce
from operator import add
nums = [1, 2, 3]
print(reduce(add, nums)) # 6
```
"""
name = "use-operator"
code = 118
categories = ("operator",)
BINARY_OPERATORS = {
"+": "add",
"in": "contains",
"/": "truediv",
"//": "floordiv",
"&": "and_",
"^": "xor",
"|": "or_",
"**": "pow",
"is": "is_",
"is not": "is_not",
"<<": "lshift",
"%": "mod",
"*": "mul",
"@": "matmul",
">>": "rshift",
"-": "sub",
"<": "lt",
"<=": "le",
"==": "eq",
"!=": "ne",
">=": "ge",
">": "gt",
}
UNARY_OPERATORS = {
"~": "invert",
"-": "neg",
"not": "not_",
"+": "pos",
}
def check(node: FuncItem, errors: list[Error]) -> None:
func_type = get_function_type(node)
match node:
case FuncItem(
arg_names=[lhs_name, rhs_name],
arg_kinds=[ArgKind.ARG_POS, ArgKind.ARG_POS],
body=Block(
body=[
ReturnStmt(
expr=OpExpr(
op=op,
left=NameExpr(name=expr_lhs),
right=NameExpr(name=expr_rhs),
)
| ComparisonExpr(
operators=[op],
operands=[
NameExpr(name=expr_lhs),
NameExpr(name=expr_rhs),
],
),
)
]
),
) if func_name := BINARY_OPERATORS.get(op):
if func_name == "contains":
# operator.contains has reversed parameters
expr_lhs, expr_rhs = expr_rhs, expr_lhs
if lhs_name == expr_lhs and rhs_name == expr_rhs:
errors.append(
ErrorInfo.from_node(
node,
f"Replace {func_type} with `operator.{func_name}`",
)
)
case FuncItem(
arg_names=[name],
arg_kinds=[ArgKind.ARG_POS],
body=Block(
body=[
ReturnStmt(
expr=UnaryExpr(
op=op,
expr=NameExpr(name=expr_name),
)
)
]
),
) if name == expr_name:
if func_name := UNARY_OPERATORS.get(op):
errors.append(
ErrorInfo.from_node(
node,
f"Replace {func_type} with `operator.{func_name}`",
)
)
def get_function_type(node: FuncItem) -> str:
if isinstance(node, LambdaExpr):
try:
return f"`{_stringify(node)}`"
except ValueError:
return "lambda"
return "function"
|
