Why do most programming languages only have binary equality comparison operators?

Question

In natural languages, we would say \"some color is a primary color if the color is red, blue, or yellow.\"

In every programming language I\'ve seen, that translates

Answer 1

In perl 6 you could do this with junctions:

if $color eq 'Red'|'Blue'|'Green' {
    doit()
}

Alternately you could do it with the smart match operator (~~). The following is roughly equivalent to python's if value in list: syntax, except that ~~ does a lot more in other contexts.

if ($color ~~ qw/Red Blue Green/) {
    doit()
}

The parens also make it valid perl 5 (>=5.10); in perl 6 they're optional.