-sub INVALID_BOOLEAN_STRING_EXCEPTION ()
- { 'The given value does not seem to be interpretable as a Boolean value' }
-
-use vars qw( %strings );
-
-%strings = (
- '0' => 0, '1' => 1, # C
- '-1' => 1, # BASIC
- 'nil' => 0, 't' => 1, # LISP
- 'false' => 0, 'true' => 1, # Pascal
- 'off' => 0, 'on' => 1,
- 'no' => 0, 'yes' => 1,
- 'n' => 0, 'y' => 1,
+use constant INVALID_BOOLEAN_STRING_EXCEPTION =>
+ q{The given value does not seem to be interpretable as a Boolean value};
+
+our %strings = (
+ '0' => 0, '1' => 1, # C
+ '-1' => 1, # BASIC
+ 'nil' => 0, 't' => 1, # LISP
+ 'false' => 0, 'true' => 1, # Pascal
+ 'off' => 0, 'on' => 1,
+ 'no' => 0, 'yes' => 1,
+ 'n' => 0, 'y' => 1,