exportMutable -- export mutable symbols from a package

• Usage:

  exportMutable {"symbol1", "symbol2", ...}

• Inputs:
  • a list, containing strings interpreted as names of symbols belonging to the package
• Outputs:
  • a list, the list of exported symbols
• Consequences:

  • the names of symbols in the sequence, which should refer to variables defined in the package, are made available to the user of the package, in such a way that their values may be modified by the user This function is needed much less frequently than export. For an example, see an example of a package.No single-letter symbol should be exported, as such symbols are reserved as variables for the user.Use importFrom to import private symbols of a package.