#!/usr/bin/perl -w
# commify_series - show proper comma insertion in list output

@lists = (
    [ 'just one thing' ],
    [ qw(Mutt Jeff) ],
    [ qw(Peter Paul Mary) ],
    [ 'To our parents', 'Mother Theresa', 'God' ],
    [ 'pastrami', 'ham and cheese', 'peanut butter and jelly', 'tuna' ],
    [ 'recycle tired, old phrases', 'ponder big, happy thoughts' ],
    [ 'recycle tired, old phrases', 
      'ponder big, happy thoughts', 
      'sleep and dream peacefully' ],
    );

foreach $aref (@lists) {
    print "The list is: " . commify_series(@$aref) . ".\n";
} 

sub commify_series {
    my $sepchar = grep(/,/ => @_) ? ";" : ",";
    (@_ == 0) ? ''                                      :
    (@_ == 1) ? $_[0]                                   :
    (@_ == 2) ? join(" and ", @_)                       :
                join("$sepchar ", @_[0 .. ($#_-1)], "and $_[-1]");
}