Minor cleaning up of the FUN and ... to be used subsequently. This does only very minor
things as it is run even if useCache = FALSE, i.e., even if the Cache is skipped.
matchCall2(definition, call, envir, envir2 = parent.frame(), FUN)a function, by default the function from which
match.call is called. See details.
an unevaluated call to the function specified by
definition, as generated by call.
an environment, from which the ... in call
are retrieved, if any.
Environment. The environment where matchCall2 was called.
Either a function (e.g., rnorm), a function call (e.g., rnorm(1)),
or an unevaluated function call (e.g., using quote()).
A named list with call (the original call, without quote),
FUNorig, the original value passed by user to FUN, and usesDots which
is a logical indicating whether the ... are used.