my $fractionValue =
    ( $str =~ m{^(\d+)/([1-9]\d*)} )   # regex match will evaluate to true or false
    ?            # the "ternary operator" -- if above condition is true, then...
    $1/$2        #   return this value (using the 1st and 2nd matched digit strings
    :            # otherwise (if above condition was false), ...
    "undefined"  #   return this value
    ;            # end of statement

##</code><code>##

/blah/
m/blah/
m=blah=
m!blah!
m{blah}

##</code><code>##

/http:\/\/my\/path\/to\/insanity/
m{my/path/back/to/sanity}

##</code><code>##

$_ = "123.456/789-0";
if ( /(\d+)\D(\d+)\D(\d+)/ ) {
    printf( "Found three numbers: %d was between %d and %d\n", $2, $1, $3 );
}

##</code><code>##

if ( $_ =~ /(\d+)\D(\d+)\D(\d+)/ ) { ...