RMethodUtils

Description

These are utility functions to support the definition and use of formal methods. Most of them will not normally be called directly by the user.

makeGeneric:

Makes a generic function object corresponding to the given function name. and optional definition.

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 method assignment conforms if either method and 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.

defaultDumpName:

the default name to be used for dumping a method.

getAllMethods:

a generic function (with methods) representing the merge of all the versions of f on the specified packages (anything on the current search path by default).

If the generic f has a group generic, methods for this group generic (and further generations of group generics, if any) are also merged.

The merging rule is as follows: each generic is merged across packages, and the group generics are then merged, finally adding the directly defined methods of f.

The effect of the merging rule is that any method directly defined for f on any included package overrides a method for the same signature defined for the group generic; similarly for the group generic and its group, if any, etc.

For f or for a specific group generic, methods override in the order of the packages being searched. A method for a particular signature on a particular package overrides any methods for the same signature on packages later on in the list of packages being searched.

The slot "allMethods" of the merged methods list is set to a copy of the methods slot; this is the slot where inherited methods are stored.

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).

getGeneric:

return the definition of the function named f as a generic.

If there is no definition in the current search list, throws an error or returns NULL according to the value of mustFind.

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:

return the groups to which this generic belongs.

If recursive=TRUE, also all the group(s) of these groups.

getGroupMembers, setGroupMembers:

Get or set the known members of the group generic function f.

matchSignature

Matches the signature object (a partially or completely named subset of the arguments of fun), and return a vector of all the classes in the order specified by names. The classes not specified by `signature' will be "ANY" in the value.

The formal arguments of fun must agree with names (usually the formal arguments of the generic function) as well, and matchSignature checks this.

getMethodsMetaData, assignMethodsMetaData, mlistMetaName:

utilities to manage methods list objects in a particular database. Not to be called directly.

getFromMethodMetaData, assignToMethodMetaData, removeFromMethodMetaData

Functions to manage the session metadata for methods. Don't call these directly.

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.

is.primitive

Is this object a primitive function (either a builtin or special)?

getFromMethodMetaData, assignToMethodMetaData, removeFromMethodMetaData

Functions to manage the session metadata for methods. Don't call these directly.

is.primitive

Is this object a primitive function (either a builtin or special)?

removeMethodsObject:

remove the metadata object containing methods for f.

findUnique:

Find the first position on the search list containing object what; if more than one is found, a warning message is generated, using message to identify what was being searched for. If doFind is supplied, it's the version of find used to do the search (e.g., findFunction.

cacheMetaData, cacheGenericsMetaData, setPrimitiveMethods:

Utilities for ensuring that the session-scope 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 database is attached or detached.

The environment must be one of the environments on the current search list; note in particular that even on detaching (attach=FALSE), the environment will normally still be on the search list.

The setPrimitiveMethods function resets the caching information for a particular primitive function. Don't call it directly.

printNoClass,print.default :

printNoClass is equivalent to the version of print.default in the base package. The methods package overrides the latter function to provide meaningful printing for formally defined classes, and printNoClass is used to get the original default printing.

Usage

makeGeneric(f, fdef, keepMethods=TRUE, useAsDefault=NA, group=character(), valueClass=character())

makeStandardGeneric(f, fdef)

generic.skeleton(name, fdef, fdefault)

defaultDumpName(generic, signature)

getAllMethods(f, libs=search())

setAllMethodsSlot(mlist)

doPrimitiveMethod(name, def, call=sys.call(-1), ev=sys.frame(-2))

conformMethod(signature, mnames, fnames)

getGeneric(f, mustFind=FALSE)

getGroup(fdef, recursive=FALSE)

getGroupMembers(f, fdef = getGeneric(f))
setGroupMembers(f, members, fdef = getGeneric(f))

matchSignature(names, signature, fun)

## manage method metadata
getFromMethodMetaData(name)

assignToMethodMetaData(name, value)

removeFromMethodMetaData(name)

removeMethodsObject(f, where)

findUnique(what, doFind, message)

MethodAddCoerce(method, argName, thisClass, methodClass)

is.primitive(fdef)

copyEnvironment(object, exceptions)

cacheMetaData(envir, attach = TRUE)

cacheGenericsMetaData(generics, attach = TRUE, envir)

setPrimitiveMethods(f, fdef, code, generic, mlist)

printNoClass(x, digits, quote, na.print, print.gap, right, ...)

print.default(x, ...)