add.backtick	add.backtick
dt.calculate	dt.calculate
dt.choose.cols	dt.choose.cols
dt.choose.rows	dt.choose.rows
dt.count.rows	dt.count.rows
dt.define.variable	dt.define.variable
dt.first.k.rows	dt.first.k.rows
dt.last.k.rows	dt.last.k.rows
dt.remove.variables	dt.remove.variables
dt.sort	dt.sort
reduce.vector.expression	reduce.vector.expression
