Function is_constant

mypyc/irbuild/util.py:274–295

Check whether we allow an expression to appear as a default value. We don't currently properly support storing the evaluated values for default arguments and default attribute values, so we restrict what expressions we allow. We allow literals of primitives types, None, and referen

(e: Expression)

def is_constant(e: Expression) -> bool:
    """Check whether we allow an expression to appear as a default value.

    We don't currently properly support storing the evaluated
    values for default arguments and default attribute values, so
    we restrict what expressions we allow.  We allow literals of
    primitives types, None, and references to Final global
    variables.
    """
    return (
        isinstance(e, (StrExpr, BytesExpr, IntExpr, FloatExpr))
        or (isinstance(e, UnaryExpr) and e.op == "-" and isinstance(e.expr, (IntExpr, FloatExpr)))
        or (isinstance(e, TupleExpr) and all(is_constant(e) for e in e.items))
        or (
            isinstance(e, RefExpr)
            and e.kind == GDEF
            and (
                e.fullname in ("builtins.True", "builtins.False", "builtins.None")
                or (isinstance(e.node, Var) and e.node.is_final)
            )
        )
    )


def bytes_from_str(value: str) -> bytes: