43 lines
819 B
Rust
43 lines
819 B
Rust
// lib/option.rs
|
|
|
|
tag t[T] {
|
|
none;
|
|
some(T);
|
|
}
|
|
|
|
type operator[T, U] = fn(&T) -> U;
|
|
|
|
fn get[T](&t[T] opt) -> T {
|
|
alt (opt) {
|
|
case (some[T](?x)) {
|
|
ret x;
|
|
}
|
|
case (none[T]) {
|
|
fail;
|
|
}
|
|
}
|
|
fail; // FIXME: remove me when exhaustiveness checking works
|
|
}
|
|
|
|
fn map[T, U](&operator[T, U] f, &t[T] opt) -> t[U] {
|
|
alt (opt) {
|
|
case (some[T](?x)) {
|
|
ret some[U](f(x));
|
|
}
|
|
case (none[T]) {
|
|
ret none[U];
|
|
}
|
|
}
|
|
fail; // FIXME: remove me when exhaustiveness checking works
|
|
}
|
|
|
|
// Local Variables:
|
|
// mode: rust;
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// compile-command: "make -k -C .. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
|
|
// End:
|
|
|