R/utils-getS4.R

In fBasics: Rmetrics - Markets and Basic Statistics

# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR Description. See the
# GNU Library General Public License for more details.
#
# You should have received a copy of the GNU Library General
# Public License along with this library; if not, write to the
# Free Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA


################################################################################
# FUNCTION:                 DESCRIPTION:
#  getCall                   Extracts the call slot from a S4 object
#  getModel                  Extracts the model slot from a S4 object
#  getTitle                  Extracts the title slot from a S4 object
#  getDescription            Extracts the description slot from a S4 object
#  getSlot                   Extracts a specified slot from a S4 object
#  getArgs                   Shows the arguments of a S4 functiong
################################################################################


if(getRversion() < "2.14") {
  getCall <- function(x) slot(x, "call")
} ## since 2.14.0, getCall() is an S3 generic in 'stats'
## *AND* its default method also works for S4 and a "call" slot

# ------------------------------------------------------------------------------


getModel <-
  function(object)
  {
    # A function implemented by Tobias Setz
    
    # FUNCTION: 
    
    # Return Value:
    UseMethod("getModel")
  }

getModel.default <-
  function(object)
  {
    # A function implemented by Rmetrics
    
    # Description:
    #   gets the "model" slot from an object of class 4
    
    # Arguments:
    #   object - an object of class S4
    
    # FUNCTION:
    
    # Return Value:
    slot(object, "model")
  }


# ------------------------------------------------------------------------------


getTitle <-
  function(object)
  {
    # A function implemented by Rmetrics
    
    # Description:
    #   gets the "title" slot from an object of class 4
    
    # Arguments:
    #   object - an object of class S4
    
    # FUNCTION:
    
    # Return Value:
    slot(object, "title")
  }


# ------------------------------------------------------------------------------


getDescription <-
  function(object)
  {
    # A function implemented by Rmetrics
    
    # Description:
    #   Extracts the "description" slot from an object of class 4
    
    # Arguments:
    #   object - an object of class S4
    
    # FUNCTION:
    
    # Return Value:
    slot(object, "description")
  }


# ------------------------------------------------------------------------------


getSlot <-
  function(object, slotName)
  {
    
    # a simple wrapper around slot to avoid compatibilty troubles with
    # other packages.
    
    # FUNCTION:
    
    slot(object, slotName)
  }


# ------------------------------------------------------------------------------


getArgs <-
  function(f, signature = character())
  {
    # A function implemented by Diethelm Wuertz
    
    # Description:
    #   Shows the arguments of a S4 functiong
    
    # Arguments:
    #   f - a generic function or the character-string name of one
    #   signature - the signature of classes to match to the arguments
    #       of f
    
    # Note:
    #   such a function is missing in the methods package,
    #   see, e.g he function getMethod()
    
    # FUNCTION:
    
    # Get arguments:
    fun <- getMethod(f, signature)@.Data
    test <- class(try(body(fun)[[2]][[3]], silent = TRUE))
    
    if (test == "function") {
      ans <- args(body(fun)[[2]][[3]])
    } else {
      ans <- args(fun)
    }
    
    cat(substitute(f), ",", paste(signature, collapse = ","), ":\n",
        sep = "")
    
    # Return Value:
    ans
  }


################################################################################