The matches operator #

Syntax #

V@[matches_expr] ::= V@[spec_expr] matches R@[pattern] &&  V@[spec_expr]
               | V@[spec_expr] matches R@[pattern] ==> V@[spec_expr]

Typing #

The left-hand side should be of a type that matches the R@[pattern], while the right-hand side should have type bool. The right-hand side may reference variables bound by the pattern.

The V@[matches_expr] as a whole has type bool.

Semantics #

The "matches-and" expression expr matches pat && condition is equivalent to:

match expr {
    pat => condition,
    _ => false,
}

The "matches-implies" expression expr matches pat ==> condition is equivalent to:

match expr {
    pat => condition,
    _ => true,
}