Code repository changed from R-Forge to Codeberg at: https://codeberg.org/zeileis/Formula/
Added basic altdoc page with overview and documentation at: https://zeileis.codeberg.page/Formula/
Converted the package vignette from Sweave to rmarkdown.
dot handling in model.matrix() method when setting up the
terms (reported by Kevin Tappe).model.part() method tries to avoid calling has_dot() by checking the
data attributes first. This can greatly improve speed when there are lots
of variables in a model part that is actually not of interest.Extended processing of formulas with one or more . on the
right-hand side: In addition to "separate" and "sequential" processing,
there is now dot = "previous" which resolves the . relative to
the previous right-hand side part.
model.part() failed in case of variables/terms with very long
names. Now deparse(..., width.cutoff = 500) is used to support
very long variable names as well.
Enhance Formula() so that if a Formula is supplied it is simply
returned unchanged (rather than throwing a warning).
Enhance update() method for Formula object so that also the "new"
formula can be a Formula object.
cbind(), log(), or Surv()) and one ore more . on the
right-hand side. The terms() and hence the model.frame() now work
smoothly. When using model.part() the same Formula (plus dot
argument) has to be supplied when preparing the model.frame() and
the model.part().. on the
right-hand side.str() method.CITATION was incorrect and is fixed now.All methods returning formula or Formula objects now preserve the
environment of the originally supplied object by default.
The default and formula methods of as.Formula() methods now also take
an env argument.
terms = FALSE argument to model.part() method for Formula
objects. This can be leveraged when processing multiple offsets.
For example for y ~ x + offset(o1) | z + offset(o2). See ?model.part
for a worked example.Package now published in Journal of Statistical Software:
doi:10.18637/jss.v034.i01
and citation("Formula") within R.
Added an all.equal() method for Formula objects that produces
more intelligible output in case the result is not TRUE.
Fixed an error of the update() method for Formula objects
without LHS.
Major revision (not fully backward compatible) to enable support
for multiple responses and multiple parts on the right-hand side
such as
y1 | y2 ~ x,
y1 + y2 ~ x1 + x2 | z1, or
y ~ u1 + u2 | v1 | x1 + x2
and combinations of these.
Formula objects now consist of the original formula plus two
attributes "lhs" and "rhs" that contain the parts of the decomposed
left- and right-hand side, respectively.
Most methods take arguments "lhs" and "rhs" which allow selection
of the desired parts on the left- and right-hand side respectively,
e.g., in a model.frame() or model.matrix().
The previous arguments response = TRUE/FALSE and
part = "first"/"second"/"both" were not flexible enough anymore
and have been deprecated. Use the streamlined lhs/rhs arguments
instead.
vignette("Formula", package = "Formula") illustrates usage of
the tools provided by the package and explains the ideas underlying
its implementation.
Excluded has.intercept() functionality, rely on standard terms attribute
instead.
Added CITATION file.
Added a has.intercept() function with methods for formula and
Formula objects.
Change the default value for model.frame.Formula: "both" for a
two-part formula and "first" otherwise.
as.Formula() failed for very long formulas.First CRAN release of package Formula for extended
formula processing. This package is still under development
and the interface might change in future versions.
Currently, this enables processing of formulas such as
y ~ x1 + x2 | z1 + z2 + z3
with two parts on the right hand side.
Generalization to further formulas are planned (i.e.,
not implemented yet), e.g.,
y1 + y2 ~ x1 + x2 + x3 or
y ~ x1 + x2 | u1 | v1 + v2 + v3 | ...
i.e., multiple responses and multi-part formulas.