Overlaps With

overlaps-with.p6

use Test;

sub overlaps-with( $r1, $r2 ) { 
			$r1.min ~~ $r2 and $r1.max ~~ $r2 or $r2.min ~~ $r1 and $r2.max ~~ $r1
		or ( $r1.min == $r2.min and ($r1.max <= $r2.max or $r2.max <= $r1.max) )
		or ( $r2.min < $r1.min < $r2.max <= $r1.max )
		or ( $r1.min < $r2.min < $r1.max <= $r2.max );
}

my @range-tests = (
    [ $(0..6),      $(6^..12),      False ],
    [ $(12^..^23),  $(23..44),      False ],
    [ $(23..44),    $(42..64),      True  ],
    [ $(6^..^7),    $(6^..^8),      True  ],
    [ $(6^..^7),    $(7^..^8),      False ],
    [ $(-6^..^7),   $(-7^..^8),     True  ],
    [ $(-6^..^7),   $(-7..-6),      False ],
    [ $(3^..^7),    $(6^..^8),      True  ],
    [ $(3^..^20),   $(6^..^8),      True  ],
    [ $(3^..^20),   $(6^..^8),      True  ],
    [ $(6^..^8),    $(3^..^20),     True  ],
    [ $(6..2),      $(2..5),        False ],
    [ $(0..0),      $(0..0),        True  ],
    [ $(-10..10),   $(0..0),        True  ],
    [ $(0..2),      $(0^..^2),      True  ],
    [ $(5^..^6),    $(5.5^..^5.6),  True  ],
    [ $(5^..^6),    $(5.5^..6),     True  ],
    [ $(5.5..6),    $(5..6),        True  ],
    [ $(5.5^..^5.6), $(6..7),       False ],
);

for @range-tests -> [ $r1, $r2, $outcome ] {
    is overlaps-with( $r1, $r2 ), $outcome, "$r1.gist() overlaps $r2.gist()";
    is overlaps-with( $r2, $r1 ), $outcome, "$r2.gist() overlaps $r1.gist()";
}