EXPR->* - The Dereference Operator

<< Symbolic (or Soft) References

<< Perl Tutorials - Herong's Tutorial Examples

This section provides a tutorial example on how to use symbolic references with the dereference operator like EXPR->[*], EXPR->{*}, or EXPR->(*) for array elements, hash elements and function calls.

As mentioned in the previous section, if a symbolic reference is used with a subscription of [*], {*}, or (*), the dereference operator, -> can be used between the identifier string expression and the subscription. Note that subscription [*] is used for array elements, {*} is used for hash elements, (*) is used for function calls.

The following tutorial program shows you some examples. Note that you can not use -> to access hard slices.

#- SoftRef3.pl
#- Copyright (c) 1999 by Dr. Herong Yang, http://www.herongyang.com/
#
   $name = 'foo';
   @name = ('foo');
   %name = ('i', 'foo');

   $name->[0] = 30; print "$foo[0]\n";   
   $name->[0,1] = (40,41); print "$foo[0]\n";     # not working
   $name->{'k'} = 60; print "$foo{k}\n";  
   $name->{'k','l'} = (70,71); print "$foo{k}\n"; # not working
   $name->(80);                           

   'foo'->[0] = 130; print "$foo[0]\n";   
   ('bla','foo')->{'k'} = 160; print "$foo{k}\n";  
   ('f'.'oo')->(180);                           

   $name[0]->[0] = 230; print "$foo[0]\n";
   $name{'i'}->{'k'} = 260; print "$foo{k}\n";
   &name->(280);

sub foo {print "$_[0]\n";}
sub name {return 'foo';}

Here is the output of the tutorial program:

30
30
60
60
80
130
160
180
230
260
280

Sections in This Chapter

Using Symbolic References

$$name - Replacing Identifiers by Scalar Variables

${EXPR} - Replacing Identifiers by Expressions

EXPR->* - The Dereference Operator

$$$name - Nested Symbolic References