feat: wip on CSS value matcher

packages/css-value-parser/src/ast-tools/matcher-iterator.ts

@@ -0,0 +1,76 @@
+export type CombinationGenerator<T> = Generator<
+    CombinationResult<T>,
+    CombinationResult<T>,
+    boolean | undefined
+>;
+export type CombinationResult<T> = {
+    combination: T[];
+    last: T;
+    takeBack: T[];
+};
+export function* combinationIterator<T>(allOptions: T[]): CombinationGenerator<T> {
+    const stack: { options: T[]; start: T[]; index: number }[] = [
+        { options: [...allOptions], start: [], index: 0 },
+    ];
+    const prevCombinations: T[] = [];
+    while (true) {
+        const context = stack[stack.length - 1]!;
+        const { options, start, index } = context;
+        // add results
+        const added = options[index];
+        const combination = start.concat(added);
+        const result = {
+            combination: combination,
+            last: added,
+            takeBack:
+                combination.length >= prevCombinations.length
+                    ? []
+                    : prevCombinations.slice(prevCombinations.length - combination.length),
+        };
+        prevCombinations.length = 0;
+        prevCombinations.push(...combination);
+        // progress position
+        if (context.index < options.length - 1) {
+            context.index++;
+        } else {
+            stack.pop();
+        }
+        // add sub options to context
+        if (options.length > 1) {
+            stack.push({
+                options: [...options.slice(0, index), ...options.slice(index + 1)],
+                start: combination,
+                index: 0,
+            });
+        }
+        const stopStack = yield result;
+        if (stopStack === false) {
+            stack.pop();
+            yield result;
+        }
+        if (!stack.length) {
+            return result;
+        }
+    }
+}
+
+// const ABC = combinationIterator(["A", "B", "C"]);
+// for (const option of ABC) {
+//   console.log(option.combination.join(" "));
+//   if (option.combination[1] === "B") {
+//     ABC.next(false);
+//   }
+// }
+
+// const iterator = combinationIterator(["A", "B", "C", "D", "E", "F", "G", "H"]);
+// let i = 0;
+// // eslint-disable-next-line no-constant-condition
+// while (true) {
+//   const { value, done } = iterator.next();
+//   console.log(value.combination.join(" "));
+//   if (done) {
+//     break;
+//   }
+//   i++
+// }
+// console.log(i);