These functions are the extensions that allow stepper objects to work with vctrs.

## Usage

```
# S3 method for almanac_stepper
vec_arith(op, x, y, ...)
# S3 method for almanac_stepper.almanac_stepper
vec_ptype2(x, y, ..., x_arg = "", y_arg = "")
# S3 method for almanac_stepper.almanac_stepper
vec_cast(x, to, ..., x_arg = "", to_arg = "")
```