61 lines
1.3 KiB
Rust
61 lines
1.3 KiB
Rust
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import option;
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import option::some;
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import option::none;
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tag t[T, U] { left(T); right(U); }
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type operator[T, U] = fn(&T) -> U ;
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fn either[T, U,
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V](&operator[T, V] f_left, &operator[U, V] f_right, &t[T, U] value)
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-> V {
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alt (value) {
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case (left(?l)) { f_left(l) }
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case (right(?r)) { f_right(r) }
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}
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}
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fn lefts[T, U](&(t[T, U])[] eithers) -> T[] {
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let T[] result = ~[];
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for (t[T, U] elt in eithers) {
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alt (elt) {
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case (left(?l)) { result += ~[l] }
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case (_) {/* fallthrough */ }
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}
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}
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ret result;
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}
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fn rights[T, U](&(t[T, U])[] eithers) -> U[] {
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let U[] result = ~[];
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for (t[T, U] elt in eithers) {
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alt (elt) {
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case (right(?r)) { result += ~[r] }
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case (_) {/* fallthrough */ }
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}
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}
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ret result;
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}
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fn partition[T, U](&(t[T, U])[] eithers) -> tup(T[], U[]) {
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let T[] lefts = ~[];
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let U[] rights = ~[];
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for (t[T, U] elt in eithers) {
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alt (elt) {
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case (left(?l)) { lefts += ~[l] }
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case (right(?r)) { rights += ~[r] }
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}
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}
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ret tup(lefts, rights);
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}
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//
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// Local Variables:
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// mode: rust
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// fill-column: 78;
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// indent-tabs-mode: nil
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// c-basic-offset: 4
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// buffer-file-coding-system: utf-8-unix
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// compile-command: "make -k -C $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
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// End:
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//
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