getS3method
Get An S3 Method
Description
Retrieves an S3 method of generic function for a given class.
Usage
getS3method(f, class, optional = FALSE)
Arguments
| f |
a character string giving the name of generic function.
|
| class |
a character string giving the class name for which the method is implemented.
|
| optional |
a logical value. If TRUE, the function returns NULL when no generic function
or method is found. If FALSE (the default), the function stops with error message.
|
Details
This function is used to get an S3 method with the given generic function f and
the class name class. Normally, the S3 method name has the format f.class.
First, the f generic function is found and checked in the known generic list.
If it is not found, NULL is returned, or the function is stopped with an error message, depending
on the optional.
After that, the method f.class is found in the S3 method table. If it is not found,
NULL is returned or the function is stopped with an error message, depending on the optional.
Value
returns the found S3 method. If it cannot be found, returns NULL or stops with an error message.
See Also
Examples
exists("print.lm") # TRUE
head(getS3method("print","lm"))
exists("print.hclust") # FALSE
head(getS3method("print","hclust"))
try(getS3method("foo")) # Error: no function 'foo' could be found
getS3method("foo", optional = TRUE) # NULL
try(getS3method("print", "foo_class")) # Error: S3 method 'print.foo_class' not found
getS3method("print", "foo_class", optional = TRUE) # NULL