$$$name - Nested Hard References

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This section provides a tutorial example on how to use nested references like $$$name, or $s->()->()->().

As mentioned in the previous section, hard references can be nested with other hard references or symbolic references. Here is a tutorial program to prove that:

#- HardRef4.pl
#- Copyright (c) 1999 by Dr. Herong Yang, http://www.herongyang.com/
#
   $z = "99.99";
   $y = \$z;
   $x = \$y;
   $a = 'y';
   $b = \$a;
   print "$$$x\n";
   print "$$$a\n";
   print "$$$$b\n";
   print &f()->()->(), "\n";
sub f {return \&g;}
sub g {return \&h;}
sub h {return 'Hello';}

Here is the output of the tutorial program:

99.99
99.99
99.99
Hello

Do you understand why we are getting those values in the output?

Sections in This Chapter

\* - Creating Hard References

Using Hard References

$$name - Replacing Identifiers by Scalar Variables

${EXPR} - Replacing Identifiers by Expressions

EXPR->* - The Dereference Operator

$$$name - Nested Hard References

\$b-\$a - Using Hard References in Other Operations