Interpolation.pm

• The syntax actually looks like this:

 use Interpolation '$' => \&currency,
 'q' => \&quote_for_CSV,
 'Cap' => sub { ucfirst lc $_[0] };

 $s = "$${$PROFITS} in the state of $Cap{$state}";
 $t .= qq{The data are: "$q{$data}".};

• Prevents cluttering of code with lost of calls to formatting functions

• Attention focused on output rather than on formatting code

• Define formatters with mnemonic names like $currency or $Cap.

• Clever hack:

 use Interpolation 's' => 'sprintf1';

 print "Profits were up by $s{'%2.2f',$amt} percent.\n";

Inserts sprintf call into a quoted string.