This set of S3 classes describe the action of dplyr verbs. These are currently used for SQL sources to separate the description of operations in R from their computation in SQL. This API is very new so is likely to evolve in the future.
op_base(name, src, x, vars)op_single(name, x, dots = list(), args = list())
add_op_single(name, .data, dots = list(), args = list())
op_double(name, x, y, args = list())
op_grps(op)
op_vars(op)
op_sort(op)
op_vars and op_grps compute the variables and groups from
a sequence of lazy operations. op_sort tracks the order of the
data for use in window functions.