518dc52f85
This changes the indexing syntax from .() to [], the vector syntax from ~[] to [] and the extension syntax from #fmt() to #fmt[]
40 lines
1000 B
Rust
40 lines
1000 B
Rust
// lib/option::rs
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tag t<@T> { none; some(T); }
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fn get<@T>(opt: &t<T>) -> T {
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alt opt { some(x) { x } none. { fail "option none" } }
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}
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fn map<@T, @U>(f: &block(&T) -> U, opt: &t<T>) -> t<U> {
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alt opt { some(x) { some(f(x)) } none. { none } }
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}
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fn is_none<@T>(opt: &t<T>) -> bool {
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alt opt { none. { true } some(_) { false } }
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}
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fn is_some<@T>(opt: &t<T>) -> bool { !is_none(opt) }
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fn from_maybe<@T>(def: &T, opt: &t<T>) -> T {
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alt opt { some(x) { x } none. { def } }
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}
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fn maybe<@T, @U>(def: &U, f: &block(&T) -> U, opt: &t<T>) -> U {
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alt opt { none. { def } some(t) { f(t) } }
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}
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// Can be defined in terms of the above when/if we have const bind.
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fn may<@T>(f: &block(&T), opt: &t<T>) {
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alt opt { none. {/* nothing */ } some(t) { f(t); } }
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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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