I'm sure this is covered in one of the documents linked in the above posts, but just the same, here's what I usually do to counter my many-else-if blues:

# SWITCH: for(thing to check) {
#     /regexp/ && do { condition 1; last SWITCH; };
#     (condition) && do { condition 2; last SWITCH; };
#     do { catch all };
# }

[download]

This works by setting the default variable ($_) to the thing to check and performing regexps or condition ops on the default variable. The nice thing about this structure is that it's very flexible: you can use an array or scalar as the thing-to-check, you can forego the last statements and have multiple statement blocks apply, you can combine regular expressions with conditional expressions, etc. I use this structure to check for variable types sometimes, sort of a generic want function.

$ref = \@array; # or,
$ref = \%hash; # or,
$ref = \$scalar;

SWITCH: for(ref $ref) { # check variable type of referent 
    # $ref is still our reference scalar
    # now $_ contains the referent variable type
    # (eg, ARRAY, SCALAR, HASH, or object class)

    /array/i && do { 
        # do something with @$ref
        last SWITCH;
    };

    /scalar/i && do {
        # do something with $$ref
        last SWITCH;
    };

    /hash/i && do {
        # do something with %$ref
        last SWITCH;
    };

    do {
        # panic, we have no handler for this variable type!
        die "don't know what to do with ". $_;
    };
}

[download]

Hope this helps!

Alakaboo

In reply to (switch using for) RE: CASE statement in Perl? by mwp
in thread CASE statement in Perl? by tROCK

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