showMethods {methods}

R Documentation

Show all the methods for the specified function(s)

Description

Show a summary of the methods for one or more generic functions, possibly restricted to those involving specified classes.

Usage

showMethods(f=character(), where=-1, classes=NULL, includeDefs=FALSE, 
            inherited=TRUE, printTo = stdout())

Arguments

f	One or more function names. If omitted, all functions will be examined.
where	If where is supplied, the methods definition from that position will be used; otherwise, the current definition is used (which will include inherited methods that have arisen so far in the session). If f is omitted, where controls where to look for generic functions.
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.
printTo	The connection on which the printed information will be written. 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.

Details

The output style is different from S-Plus in that it does not show the database from which the definition comes, but can optionally include the method definitions.

Value

If printTo is FALSE, the character vector that would have been printed is returned; otherwise the value is the connection or filename.

References

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. For a discussion of details and ongoing development, see the web page http://developer.r-project.org/methodsPackage.html and the pointers from that page.

See Also

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.

Examples

## assuming the methods for plot
## are set up as in the documentation for 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)

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