Utility functions to support the definition and use of formal methods. Most of these functions will not normally be called directly by the user.
getGeneric(f, mustFind=FALSE, where, package)getGroup(fdef, recursive, where)
getGroupMembers(group, recursive = FALSE, character = TRUE)
getMethodsMetaData(f, where)
assignMethodsMetaData (f, value, fdef, where)
makeGeneric(f, fdef, fdefault =, group=list(), valueClass=character(),
package =, signature = NULL, genericFunction = NULL,
simpleInheritanceOnly = NULL)
makeStandardGeneric(f, fdef)
generic.skeleton(name, fdef, fdefault)
defaultDumpName(generic, signature)
doPrimitiveMethod(name, def, call= sys.call(sys.parent()),
ev = sys.frame(sys.parent(2)))
conformMethod(signature, mnames, fnames, f= , fdef, method)
matchSignature(signature, fun, where)
findUnique(what, message, where)
MethodAddCoerce(method, argName, thisClass, methodClass)
cacheMetaData(where, attach = TRUE, searchWhere = as.environment(where),
doCheck = TRUE)
cacheGenericsMetaData(f, fdef, attach = TRUE, where, package, methods)
setPrimitiveMethods(f, fdef, code, generic, mlist)
missingArg(symbol, envir = parent.frame(), eval)
sigToEnv(signature, generic)
rematchDefinition(definition, generic, mnames, fnames, signature)
unRematchDefinition(definition)
isRematched(definition)
asMethodDefinition(def, signature, sealed = FALSE, fdef)
addNextMethod(method, f, mlist, optional, envir)
insertClassMethods(methods, Class, value, fieldNames, returnAll)
balanceMethodsList(mlist, args, check = TRUE) # <- deprecated since R 3.2.0
getGeneric:returns the definition of the function named f as a generic.
If no definition is found, throws an
error or returns NULL according to the value of
mustFind. By default, searches in the top-level
environment (normally the global environment, but adjusted to
work correctly when package code is evaluated from the function
library).
Primitive functions are dealt with specially, since there is never
a formal generic definition for them. The value returned is the
formal definition used for assigning methods to this primitive.
Not all primitives can have methods; if this one can't, then
getGeneric returns NULL or throws an error.
getGroup:returns the groups to which this generic belongs, searching from
environment where (the global environment normally by default).
If recursive=TRUE, also all the group(s) of these groups.
getGroupMembers:Return all the members of the group generic function named
group.
If recursive is TRUE, and some members are group
generics, includes their members as well.
If character is TRUE, returns just a character
vector of the names; otherwise returns a list, whose elements may
(or may not) include either names with a package attribute or
actual generic functions.
Note that members that are not defined as generic functions will
not be included in the returned value. To see the raw data,
use getGeneric(group)@groupMembers.
getMethodsMetaData,
assignMethodsMetaData,
mlistMetaName:Utilities to get
(getMethodsMetaData) and assign
(assignMethodsMetaData) the metadata object recording the
methods defined in a particular package, or to return the mangled
name for that object (mlistMetaName).
The assign function should not be used directly. The get
function may be useful if you want explicitly only the outcome of
the methods assigned in this package. Otherwise, use
getMethods.
matchSignature:Matches the signature object (a partially or completely named
subset of the signature arguments of the generic function object
fun), and return a vector of all the classes in the order
specified by fun@signature. The classes not specified by
signature will be "ANY" in the value, but extra
trailing "ANY"'s are removed. When the input signature is
empty, the returned signature is a single "ANY" matching
the first formal argument (so the returned value is always
non-empty).
Generates an error if any of the supplied signature names are not legal; that is, not in the signature slot of the generic function.
If argument where is supplied, a warning will be issued
if any of the classes does not have a formal definition visible
from where.
MethodAddCoerce:Possibly modify one or more methods to explicitly coerce this
argument to methodClass, the class for which the method is
explicitly defined. Only modifies the method if an explicit
coerce is required to coerce from thisClass to
methodClass.
findUnique:Return the list of environments (or equivalent) having an object named
what, using environment where and its parent
environments. If more than one is found, a warning message is
generated, using message to identify what was being
searched for, unless message is the empty string.
cacheMetaData,
cacheGenericsMetaData,
setPrimitiveMethods:Utilities for ensuring that the internal information about class and method definitions is up to date. Should normally be called automatically whenever needed (for example, when a method or class definition changes, or when a package is attached or detached). Required primarily because primitive functions are dispatched in C code, rather than by the official model.
The setPrimitiveMethods function resets the caching
information for a particular primitive function. Don't call it
directly.
missingArg:Returns TRUE if the symbol supplied is missing from
the call corresponding to the environment supplied (by default,
environment of the call to missingArg). If eval is
true, the argument is evaluated to get the name of the symbol to
test. Note that missingArg is closer to the
‘Blue Book’ sense of the missing function,
not that of the current R base package implementation. But beware
that it works reliably only if no assignment has yet been made to
the argument. (For method dispatch this is fine, because
computations are done at the beginning of the call.)
balanceMethodsList:Used to be called from setMethod() and is deprecated
since R version 3.2.0.
sigToEnv:Turn the signature (a named vector of classes) into an environment
with the classes assigned to the names. The environment is then
suitable for calling MethodsListSelect, with
evalArgs=FALSE, to select a method corresponding to the
signature. Usually not called directly: see
selectMethod.
.saveImage:Flag, used in dynamically initializing the methods package from
.onLoad.
rematchDefinition,
unRematchDefinition,
isRematched:If the specified method in a call to setMethod
specializes the argument list (by replacing …), then
rematchDefinition constructs the actual method stored.
Using knowledge of how rematchDefinition works,
unRematchDefinition reverses the procedure; if given a
function or method definition that does not correspond to this
form, it just returns its argument. isRematched returns a
logical value indicating whether rematching was used when
constructing a given method.
asMethodDefinition:Turn a function definition into an object of class
'>MethodDefinition, corresponding to the
given signature (by default generates a default method
with empty signature). The definition is sealed according to
the sealed argument.
addNextMethod:A generic function that finds the next method for
the signature of the method definition method and caches
that method in the method definition (promoting the class to
"MethodWithNext"). Note that argument mlist is
obsolete and not used.
makeGeneric:Makes a generic function object corresponding to the given
function name, optional definition and optional default method.
Other arguments supply optional elements for the slots of class
'>genericFunction.
makeStandardGeneric:a utility function that makes a valid function calling
standardGeneric for name f. Works (more or less)
even if the actual definition, fdef, is not a proper
function, that is, it's a primitive or internal.
conformMethod:If the formal arguments, mnames, are not identical to the
formal arguments to the function, fnames,
conformMethod determines whether the signature and the two
sets of arguments conform, and returns the signature, possibly
extended. The function name, f is supplied for error
messages. The generic function, fdef, supplies the
generic signature for matching purposes.
The method assignment conforms if method and generic function have identical formal argument lists. It can also conform if the method omits some of the formal arguments of the function but: (1) the non-omitted arguments are a subset of the function arguments, appearing in the same order; (2) there are no arguments to the method that are not arguments to the function; and (3) the omitted formal arguments do not appear as explicit classes in the signature. A future extension hopes to test also that the omitted arguments are not assumed by being used as locally assigned names or function names in the body of the method.
defaultDumpName:the default name to be used for dumping a method.
doPrimitiveMethod:do a primitive call to builtin function name the definition
and call provided, and carried out in the environment ev.
A call to doPrimitiveMethod is used when the actual method
is a .Primitive. (Because primitives don't behave correctly as
ordinary functions, not having either formal arguments nor a
function body).
# NOT RUN {
getGroup("exp")
getGroup("==", recursive = TRUE)
getGroupMembers("Arith")
getGroupMembers("Math")
getGroupMembers("Ops") # -> its sub groups
# }
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