69 lines
1.9 KiB
JavaScript
69 lines
1.9 KiB
JavaScript
import { emptySet, add, length, forEach, has, remove } from "../../structures/set.js";
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import { getDepth, Slot } from "./value_slot.js";
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import { compareSlot } from "../compare.js";
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import { makeTypeParser } from "../../parser/type_parser.js";
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import { newDynamic } from "../../primitives/dynamic.js";
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const emptySetOfSlots = emptySet(compareSlot);
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export const findLCA = slotA => slotB => {
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if (compareSlot(slotA)(slotB) === 0) {
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return slotA;
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}
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if (getDepth(slotA) > getDepth(slotB)) {
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// we can assume that slotA.variant === "write"
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return findLCA(slotA.value.slot)(slotB);
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}
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else {
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// we can assume that slotB.variant === "write"
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return findLCA(slotA)(slotB.value.slot);
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}
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};
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// returns
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// {slotA} if slotA is younger
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// {slotB} if slotB is younger
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// {slotA, slotB} if they are concurrent (conflicting)
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export const merge = slotA => slotB => {
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const lca = findLCA(slotA)(slotB);
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if (compareSlot(lca)(slotA) === 0) {
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return add(emptySetOfSlots)(slotB);
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}
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if (compareSlot(lca)(slotB) === 0) {
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return add(emptySetOfSlots)(slotA);
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}
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const setWithA = add(emptySetOfSlots)(slotA);
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const setWithAandB = add(setWithA)(slotB);
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return setWithAandB;
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};
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export const mergeN = slots => {
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let result = slots;
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forEach(slots)(slotA => {
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forEach(slots)(slotB => {
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// compare all non-identical pairs
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if (compareSlot(slotA)(slotB) !== 0) {
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const m = merge(slotA)(slotB);
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if (length(m) === 1) {
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// if in the pair, one is an ancestor of the other,
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// only keep the other
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if (has(m)(slotA)) {
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result = remove(result)(slotB);
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}
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}
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}
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});
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});
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return result;
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};
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const mkType = makeTypeParser({
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extraBracketOperators: [
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[':=', ['=:', Slot]],
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],
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});
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export const ModuleStaticMerge = [
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["merge" , newDynamic(merge)(mkType(":=a=: -> :=a=: -> {:=a=:}"))],
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["mergeN", newDynamic(merge)(mkType("{:=a=:} -> {:=a=:}" ))],
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];
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