Description:

The Switch.pm module implements a generalized case mechanism that covers most
(but not all) of the numerous possible combinations of switch and case values
described above.
The module augments the standard Perl syntax with two new control statements:
switch and case. The switch statement takes a single scalar argument of any type,
specified in parentheses. switch stores this value as the current switch value
in a (localized) control variable. The value is followed by a block which may
contain one or more Perl statements (including the case statement described below).
The block is unconditionally executed once the switch value has been cached.
A case statement takes a single scalar argument (in mandatory parentheses if it's
a variable; otherwise the parens are optional) and selects the appropriate type
of matching between that argument and the current switch value. The type of
matching used is determined by the respective types of the switch value and the
case argument, as specified in Table 1. If the match is successful, the mandatory
block associated with the case statement is executed.