GenericFunctions {methods} | R Documentation |
The functions documented here manage collections of methods associated with a generic function, as well as providing information about the generic functions themselves.
isGeneric(f, where, fdef, getName = FALSE) isGroup(f, where, fdef) removeGeneric(f, where) standardGeneric(f) dumpMethod(f, signature, file, where, def) existsFunction(f, generic = TRUE, where) findFunction(f, generic=TRUE) dumpMethods(f, file, signature, methods, where) signature(...) removeMethods(f, where) setReplaceMethod(f, ...) getGenerics(where) allGenerics(where) callGeneric(...)
f |
The character string naming the function. |
where |
Where on the search list of attached packages to look for functions or methods. By default, use the whole search list to find the relevant object(s). |
signature |
The class signature of the relevant method. A
signature is a named or unnamed vector of character strings. If
named, the names must be formal argument names for the generic
function. If signature is unnamed, the default is to use
the first length(signature) formal arguments of the
function. |
file |
The file on which to dump method definitions. |
def |
The function object defining the method; if omitted, the current method definition corresponding to the signature. |
... |
Named or unnamed arguments to form a signature. |
generic |
In testing or finding functions, should generic
functions be included. Supply as FALSE to get only
non-generic functions. |
fdef |
Optional, the generic function definition.
Usually omitted in calls to isGeneric |
getName |
If TRUE , isGeneric returns the name of
the generic. By default, it returns TRUE . |
methods |
The methods object containing the methods to be dumped. By default,
the methods defined for this generic (optionally on the specified
where location).
|
isGeneric
:f
, and if so, is it a generic?
The getName
argument allows a function to find the name from
a function definition. If it is TRUE
then the name of the
generic is returned, or FALSE
if this is not a generic
function definition.
The behavior of isGeneric
and getGeneric
for
primitive functions is slightly different. These functions don't
exist as formal function objects (for efficiency and historical
reasons), regardless of whether methods have been defined for them.
A call to isGeneric
tells you whether methods have been
defined for this primitive function, either on database where
or anywhere in the current search list. In contrast, a call to
getGeneric
will return what the generic for that
function would be, even if no methods have been currently defined
for it.
removeGeneric
:standardGeneric
:fname
.
getMethods
:
dumpMethod
:
existsFunction
:generic==FALSE
, generic functions are not counted.
findFunction
:name
exists.
NOTE: Use this rather than find
with
mode="function"
, which is not as meaningful, and has a few subtle bugs from its use of
regular expressions.
selectMethod
:f = the name of the generic function sig = the signature of classes to match to the arguments of f.
dumpMethods
:signature
:
callGeneric
:callGeneric
,
the arguments to the current call are passed down; otherwise, the arguments
are interpreted as in a call to the generic function.
setGeneric
:
If there is already a non-generic function of this name, it will be used
to define the generic unless def
is supplied, and the current function will
become the default method for the generic.
If def
is supplied, this defines the generic function, and no default method
will exist (often a good feature, if the function should only be available for
a meaningful subset of all objects).
Arguments group
and valueClass
are retained for consistency with S-Plus, but
are currently not used.
isGeneric
:
If the fdef
argument is supplied, take this as the definition of the
generic, and test whether it is really a generic, with f
as the name of
the generic. (This argument is not available in S-Plus.)
removeGeneric
:
If where
supplied, just remove the version on this element of the search list;
otherwise, removes the first version encountered.
standardGeneric
:
Generic functions should usually have a call to standardGeneric
as their entire
body. They can, however, do any other computations as well.
The usual setGeneric
(directly or through calling
setMethod
) creates a function with a call to
standardGeneric
.
getMethods
:f
argument can be either the character string name of the generic
or the object itself
The where
argument optionally says where to look for the function, if
f
is given as the name.
dumpMethod
:The resulting source file will recreate the method.
findFunction
:generic
is FALSE, ignore generic
functions.
selectMethod
:
dumpMethods
:
If signature
is supplied only the methods matching this initial signature
are dumped. (This feature is not found in S-Plus: don't use it if you want
compatibility.)
signature
:signature
is to provide a check on which arguments you meant, as well
as clearer documentation in your method specification. In addition, signature
checks that each of the elements is a single character string.
removeMethods
:TRUE
if
f
was a generic function, FALSE
(silently) otherwise.
If there is a default method, the function will be re-assigned as
a simple function with this definition; otherwise, it will be removed. The
assignment or removal can be controlled by optional argument where
, which
defaults to the first element of the search list having a function called f
.
John Chambers
The web page http://www.omegahat.org/RSMethods/index.html is the primary documentation.
The functions in this package emulate the facility for classes and methods described in Programming with Data, (John M. Chambers, Springer, 1998). See this book for further details and examples.
setGeneric
, setClass
, showMethods