if (($i == 7) || ($i == 14) || ($i == 21) || ($i == 28) || ... ) {
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which still has a problem: unecessary parenthesis creating single-elements lists, each containing a boolean.

This is wrong. Context creates the list not parentheses. Consider the following code. All the print statements are executed.

my @ar = ( 0);   # Could be: @ar = 0; no precedence problem

unless ( 0 ) {
    print "0 is false!\n";
}

unless ( (0) ) {
    print "(0) is false!  But a list w/ 1 item is true.\n";
}

if ( @ar ) {
    print "\@ar, non-empty array is true!\n";
}
unless ( list_context() ) {
    print "scalar context!\n";
}

sub list_context {
    return 1 if wantarray;
    return;
}
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~