Handle a user function on the LEFT-hand side of a model line

The LHS analogue of rxUdfUi(). Dispatched by .rxUdfUiLhsName() on the function called on the left of ~, <- or =, and handed both sides.

Usage

rxUdfUiLhs(fun, rhs)

Arguments

fun

the LHS call, as a language object – eg dist(eta.cl)

rhs

the right-hand side, as a language object

Value

a list with the same fields rxUdfUi() returns (iniDf, before, after, replace), with one addition: replace = NULL DROPS the line, which is what a declaration that only modifies iniDf wants.

Author

Matthew L. Fidler