e5d095d67e
Now that core exports "option" as a synonym for option::t, search-and- replace option::t with option. The only place that still refers to option::t are the modules in libcore that use option, because fixing this requires a new snapshot (forthcoming).
104 lines
2.0 KiB
Rust
104 lines
2.0 KiB
Rust
/*
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Module: fun_treemap
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A functional key,value store that works on anything.
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This works using a binary search tree. In the first version, it's a
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very naive algorithm, but it will probably be updated to be a
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red-black tree or something else.
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This is copied and modified from treemap right now. It's missing a lot
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of features.
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*/
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import option::{some, none};
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import option = option;
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export treemap;
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export init;
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export insert;
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export find;
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export traverse;
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/* Section: Types */
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/*
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Type: treemap
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*/
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type treemap<K, V> = @tree_node<K, V>;
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/*
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Tag: tree_node
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*/
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enum tree_node<K, V> {
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empty,
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node(@K, @V, @tree_node<K, V>, @tree_node<K, V>)
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}
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/* Section: Operations */
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/*
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Function: init
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Create a treemap
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*/
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fn init<K, V>() -> treemap<K, V> { @empty }
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/*
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Function: insert
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Insert a value into the map
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*/
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fn insert<K: copy, V: copy>(m: treemap<K, V>, k: K, v: V) -> treemap<K, V> {
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@alt m {
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@empty { node(@k, @v, @empty, @empty) }
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@node(@kk, vv, left, right) {
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if k < kk {
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node(@kk, vv, insert(left, k, v), right)
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} else if k == kk {
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node(@kk, @v, left, right)
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} else { node(@kk, vv, left, insert(right, k, v)) }
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}
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}
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}
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/*
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Function: find
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Find a value based on the key
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*/
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fn find<K, V: copy>(m: treemap<K, V>, k: K) -> option<V> {
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alt *m {
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empty { none }
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node(@kk, @v, left, right) {
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if k == kk {
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some(v)
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} else if k < kk { find(left, k) } else { find(right, k) }
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}
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}
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}
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/*
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Function: traverse
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Visit all pairs in the map in order.
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*/
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fn traverse<K, V: copy>(m: treemap<K, V>, f: fn(K, V)) {
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alt *m {
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empty { }
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/*
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Previously, this had what looked like redundant
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matches to me, so I changed it. but that may be a
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de-optimization -- tjc
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*/
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node(@k, @v, left, right) {
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// copy v to make aliases work out
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let v1 = v;
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traverse(left, f);
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f(k, v1);
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traverse(right, f);
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}
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}
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}
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