| showMethods {methods} | R Documentation |
Show a summary of the methods for one or more generic functions, possibly restricted to those involving specified classes.
showMethods(f = character(), where = topenv(parent.frame()),
classes = NULL, includeDefs = FALSE, inherited = TRUE,
showEmpty, printTo = stdout())
f |
one or more function names. If omitted, all functions will be shown that match the other arguments. |
where |
Used only when f is missing, or length 0, to
determine which generic functions to examine. If where is
supplied, only the generic functions returned by
getGenerics(where) are eligible for printing. If
where is also missing, all the cached generic functions are
considered. |
classes |
If argument classes is supplied, it is a vector
of class names that restricts the displayed results to those methods
whose signatures include one or more of those classes. |
includeDefs |
If includeDefs is TRUE, include the
definitions of the individual methods in the printout. |
inherited |
If inherits is TRUE, then methods that
have been found by inheritance, so far in the session, will be
included and marked as inherited. Note that an inherited method
will not usually appear until it has been used in this session.
See selectMethod if you want to know what method is
dispatched for particular classes of arguments. |
showEmpty |
logical indicating whether methods with no defined
methods matching the other criteria should be shown at all. By
default, TRUE if and only if argument f is not
missing. |
printTo |
The connection on which the printed information will be
written; by default, standard output. If printTo is
FALSE, the output will be collected as a character vector and
returned as the value of the call to showMethod. See
show.
|
The name and package of the generic are followed by the list of signatures for which methods are currently defined, according to the criteria determined by the various arguments. Note that the package refers to the source of the generic function. Individual methods for that generic can come from other packages as well.
If printTo is FALSE, the character vector that would
have been printed is returned; otherwise the value is the connection
or filename, via invisible.
The R package methods implements, with a few exceptions, the programming interface for classes and methods in the book Programming with Data (John M. Chambers, Springer, 1998), in particular sections 1.6, 2.7, 2.8, and chapters 7 and 8.
While the programming interface for the methods package follows
the reference, the R software is an original implementation, so
details in the reference that reflect the S4 implementation may appear
differently in R. Also, there are extensions to the programming
interface developed more recently than the reference. See
Methods and references from there.
setMethod, and GenericFunctions
for other tools involving methods;
selectMethod will show you the method dispatched for a
particular function and signature of classes for the arguments.
## Assuming the methods for plot
## are set up as in the example of help(setMethod),
## print (without definitions) the methods that involve class "track":
showMethods("plot", classes = "track")
## Not run:
Function "plot":
x = ANY, y = track
x = track, y = missing
x = track, y = ANY
## End(Not run)
not.there <- !any("package:stats4" == search())
if(not.there) library(stats4)
showMethods(class = "mle")
if(not.there) detach("package:stats4")