base-internal              package:base              R Documentation

_I_n_t_e_r_n_a_l _F_u_n_c_t_i_o_n_s _i_n _t_h_e _B_a_s_e _P_a_c_k_a_g_e

_D_e_s_c_r_i_p_t_i_o_n:

     Internal functions in the base package, which are only
     user-visible because of the special nature of the base namespace.

_U_s_a_g_e:

     .subset(x, ...)
     .subset2(x, ...)

     .find.package(package, lib.loc = NULL, quiet = FALSE,
                   verbose = getOption("verbose"))

     .path.package(package, quiet = FALSE)

     .getRequiredPackages(file = "DESCRIPTION", quietly = FALSE,
                          useImports = FALSE)
     .getRequiredPackages2(pkgInfo, quietly = FALSE, lib.loc = NULL,
                           useImports = FALSE)

_A_r_g_u_m_e_n_t_s:

       x: object from which to extract elements.

 package: the name of a package

 lib.loc: a character vector describing the location of R library trees
          to search through, or 'NULL'.  The default value of 'NULL'
          corresponds to all libraries currently known.

   quiet: logical.  Should this not give warnings or an error if the
          package(s) are not found?

useImports: logical.  Should  the 'Imports' field be processed?

 verbose: a logical.  If 'TRUE', additional diagnostics are printed.

    file: The full path to the 'DESCRIPTION' file of a package.

 quietly: logical: should progress messages be given.

 pkginfo: A processed 'DESCRIPTION' file of class
          '"packageDescription2"'.

_D_e_t_a_i_l_s:

     The functions '.subset' and '.subset2' are essentially equivalent
     to the '[' and '[[' operators, except methods that dispatch does
     not take place.  This is to avoid expensive unclassing when
     applying the default method to an object.  They should not
     normally be invoked by end users.

     '.find.package' returns the paths to the locations where the given
     packages can be found.  If 'lib.loc' is 'NULL', then then attached
     packages are searched before the libraries.  If a package is found
     more than once, the first match is used.  Unless 'quiet = TRUE' a
     warning will be given about the named packages which are not
     found, and an error if none are.  If 'verbose' is true, warnings
     about packages found more than once are given.

     '.path.package' returns the paths from which the named packages
     were loaded, or if none were named, for all currently loaded
     packages. Unless 'quiet = TRUE' it will warn if some of the
     packages named are not loaded, and given an error if none are. 
     This function is not meant to be called by users, and its
     interface might change in future versions.

     '.getRequiredPackages2' attaches all the packages mentioned in the
     'Depends' field: failure to find a package is an error.  It also
     checks the versions of the packages found against the depends
     field.

     '.getRequiredPackages' is a wrapper using a 'DESCRIPTION' file.

_V_a_l_u_e:

     '.find.package' and '.path.packages' return a character vector of
     paths to installed packages.

     '.getRequiredPackages' and '.getRequiredPackages2' return
     'invisible()'.

