DynScalar






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DynScalar

NAME

DynScalar - closure-in-a-box for simple scalars

SYNOPSIS

  use DynScalar;  # imports as dynamic()
  use strict;
  use vars '$name';
  
  my $foo = dynamic { "Hello, $name!\n" };
  for $name ("Jeff", "Joe", "Jonas") { print $foo }

DESCRIPTION

This module creates closures, and masks them as objects that stringify themselves when used. This allows you to make incredibly simplistic string templates:

  use DynScalar 'delay';  # import as delay()
  use strict;
  use vars qw( $name $age $sex );
  
  my $template = delay {
    "Hello, $name.  You're a good-looking $age-year-old $sex.\n"
  };
  
  while (my $rec = get_person()) {
    ($name,$age,$sex) = $rec->features;
    print $template;
  }

You can embed arbitrarily complex code in the block.

CAVEATS

Lexically scoped variables can be used inside the block, but you must do so with caution. The variable must be visible, as in this example:

  use DynScalar;
  
  my $name;
  my $str = dynamic { $name };
  for ("Jeff", "Joe", "Jonas") { $name = $_; print $str }

If you use the lexically scoped variable as the iterator variable in the loop, however, Perl will scope it even further, and the DynScalar object will not be able to see it:

  use DynScalar;
  
  my $name;
  my $str = dynamic { $name };
  # this next line will not print as you hoped
  for $name ("Jeff", "Joe", "Jonas") { print $str }

AUTHOR

  Jeff "japhy" Pinyan
  CPAN ID: PINYAN
  japhy@pobox.com
  http://www.pobox.com/~japhy/