2e90bd94de
It's still sketchy. I added a typestate annotation field to statements tagged stmt_decl or stmt_expr, because a stmt_decl statement has a typestate that's different from that of its child node. This necessitated trivial changes to a bunch of other files all over to the compiler. I also added a few small standard library functions, some of which I didn't actually end up using but which I thought might be useful anyway.
57 lines
1.1 KiB
Rust
57 lines
1.1 KiB
Rust
// lib/option.rs
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tag t[T] {
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none;
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some(T);
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}
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type operator[T, U] = fn(&T) -> U;
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fn get[T](&t[T] opt) -> T {
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alt (opt) {
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case (some[T](?x)) {
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ret x;
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}
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case (none[T]) {
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fail;
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}
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}
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fail; // FIXME: remove me when exhaustiveness checking works
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}
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fn map[T, U](&operator[T, U] f, &t[T] opt) -> t[U] {
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alt (opt) {
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case (some[T](?x)) {
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ret some[U](f(x));
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}
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case (none[T]) {
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ret none[U];
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}
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}
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fail; // FIXME: remove me when exhaustiveness checking works
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}
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fn is_none[T](&t[T] opt) -> bool {
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alt (opt) {
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case (none[T]) { ret true; }
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case (some[T](_)) { ret false; }
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}
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}
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fn from_maybe[T](&T def, &t[T] opt) -> T {
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alt(opt) {
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case (none[T]) { ret def; }
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case (some[T](?t)) { ret t; }
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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 .. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
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// End:
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