R: Utility Functions for Methods and S-Plus Compatibility

methodUtilities {methods} | R Documentation

## Utility Functions for Methods and S-Plus Compatibility

### Description

These are internal utilities, currently in the methods package, that either provide some functionality needed by the package (e.g., element matching by name), or add compatibility with S-Plus, or both.

### Usage

    functionBody(fun=sys.function(sys.parent()))

    allNames(x)

    getFunction(name, generic=TRUE, mustFind=TRUE, where)

    el(object, where)

    elNamed(x, name, mustFind=FALSE)

    formalArgs(def)

    Quote(expr)

    showDefault(object, oldMethods = TRUE)

    initMethodDispatch(where = topenv(parent.frame()))

    methodSignatureMatrix(object, sigSlots = c("target", "defined"))

### Summary of Functions

`allNames`:

  the character vector of names (unlike `names()`, never returns `NULL`).

`getFunction`:

  find the object as a function.

`el`:

  `el(object, i)` is equivalent to `object[i][[1]]` (and should typically be replaceable by object[[i]]).

`elNamed`:

  get the element of the vector corresponding to name. Unlike the `[`, `[[`, and `$` operators, this function requires `name` to match the element name exactly (no partial matching).

`formalArgs`:

  Returns the names of the formal arguments of this function.

`existsFunction`:

  Is there a function of this name? If `generic` is `FALSE`, generic functions are not counted.

`findFunction`:

  return all the indices of the search list on which a function definition for `name` exists.

  If `generic` is `FALSE`, ignore generic functions.

`showDefault`:

  Utility, used to enable `show` methods to be called by the automatic printing (via `print.default`).

  Argument `oldMethods` is deprecated as it has been unused since R >= 1.7.0.

`initMethodDispatch`:

  Turn on the internal method dispatch code. Called on loading the namespace. Also, if dispatch has been turned off (by calling `.isMethodsDispatchOn(FALSE)`—a very gutsy thing to do), calling this function should turn dispatch back on again.

`methodSignatureMatrix`:

  Returns a matrix with the contents of the specified slots as rows. The slots should be named character strings of the same length. Basically used to turn the signatures of a `"MethodDefinition"` object into a matrix for printing.

`Quote`:

  is a synonym of `quote()` and considered deprecated.

[Package methods version 4.0.5 Index]