Accessing Identifiers from Other Packages as Aliases

<< Typeglob and Importing Identifiers from Other Packages

<< Perl Tutorials - Herong's Tutorial Examples

This section provides a tutorial example on how to access identifiers from another package as aliases, *identifier = *package::identifier.

As we learned earlier, to access variables from other packages is to use their fully qualified names in the format of packageName::variableName. But this format is too long, and not easy to use, see the following program:

#- CalendarTest.pl
#- Copyright (c) 1995 by Dr. Herong Yang, http://www.herongyang.com/
#
   require CalendarModule;
   print("Date: $CalendarModule::smon");
   print(" $CalendarModule::smday");
   print(" $CalendarModule::syear\n");
   print("Leap year? ",&CalendarModule::isLeapYear(), "\n");
   exit;

To make this easier, variables from other packages can be introduced into the current package as aliases. Here is how I improved the previous program:

#- CalendarAliasTest.pl
#- Copyright (c) 1999 by Dr. Herong Yang, http://www.herongyang.com/
#
   require CalendarModule;
   *smon = *CalendarModule::smon;
   *smday = *CalendarModule::smday;
   *syear = *CalendarModule::syear;
   *isLeapYear = *CalendarModule::isLeapYear;
   print("Date: $smon");
   print(" $smday");
   print(" $syear\n");
   print("Leap year? ",&isLeapYear(), "\n");
   exit;

Sections in This Chapter

Typeglob, Symbolic Table and Identifier Aliases

Accessing Identifiers from Other Packages as Aliases

Exporting and Importing Package Identifiers