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import option;
import option::some;
import option::none;
tag t[T, U] { left(T); right(U); }
type operator[T, U] = fn(&T) -> U ;
fn either[T, U,
V](f_left: &operator[T, V], f_right: &operator[U, V],
value: &t[T, U]) -> V {
alt value { left(l) { f_left(l) } right(r) { f_right(r) } }
}
fn lefts[T, U](eithers: &(t[T, U])[]) -> T[] {
let result: T[] = ~[];
for elt: t[T, U] in eithers {
alt elt { left(l) { result += ~[l] } _ {/* fallthrough */ } }
}
ret result;
}
fn rights[T, U](eithers: &(t[T, U])[]) -> U[] {
let result: U[] = ~[];
for elt: t[T, U] in eithers {
alt elt { right(r) { result += ~[r] } _ {/* fallthrough */ } }
}
ret result;
}
fn partition[T, U](eithers: &(t[T, U])[]) -> {lefts: T[], rights: U[]} {
let lefts: T[] = ~[];
let rights: U[] = ~[];
for elt: t[T, U] in eithers {
alt elt { left(l) { lefts += ~[l] } right(r) { rights += ~[r] } }
}
ret {lefts: lefts, rights: rights};
}
//
// 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 $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End:
//
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