@thi.ng/rstream-query/xforms.js

@thi.ng/rstream based triple store & reactive query engine

import { intersection } from "@thi.ng/associative/intersection";
import { join } from "@thi.ng/associative/join";
import { equiv } from "@thi.ng/equiv";
import { LOGGER } from "@thi.ng/rstream/logger";
import { comp } from "@thi.ng/transducers/comp";
import { compR } from "@thi.ng/transducers/compr";
import { dedupe } from "@thi.ng/transducers/dedupe";
import { keySelector } from "@thi.ng/transducers/key-selector";
import { map } from "@thi.ng/transducers/map";
const intersect2 = comp(
  map(({ a, b }) => intersection(a, b)),
  dedupe(equiv)
);
const intersect3 = comp(
  map(({ s, p, o }) => intersection(intersection(s, p), o)),
  dedupe(equiv)
);
const indexSel = (key) => (rfn) => {
  const r = rfn[2];
  return compR(rfn, (acc, e) => {
    LOGGER.fine("index sel", e.key, key);
    return equiv(e.key, key) ? r(acc, e.index) : acc;
  });
};
const resultTriples = (graph) => map((ids) => {
  const res = /* @__PURE__ */ new Set();
  for (let id of ids) res.add(graph.triples[id]);
  return res;
});
const joinSolutions = (n) => map((src) => {
  let res = src[0];
  for (let i = 1; i < n && res.size; i++) {
    res = join(res, src[i]);
  }
  return res;
});
const filterSolutions = (qvars) => {
  const filterVars = keySelector([...qvars]);
  return map((sol) => {
    const res = /* @__PURE__ */ new Set();
    for (let s of sol) {
      res.add(filterVars(s));
    }
    return res;
  });
};
const limitSolutions = (n) => map((sol) => {
  if (sol.size <= n) {
    return sol;
  }
  const res = /* @__PURE__ */ new Set();
  let m = n;
  for (let s of sol) {
    res.add(s);
    if (--m <= 0) break;
  }
  return res;
});
const bindVars = (bindings) => map((sol) => {
  const res = /* @__PURE__ */ new Set();
  for (let s of sol) {
    s = { ...s };
    res.add(s);
    for (let b in bindings) {
      s[b] = bindings[b](s);
    }
  }
  return res;
});
export {
  bindVars,
  filterSolutions,
  indexSel,
  intersect2,
  intersect3,
  joinSolutions,
  limitSolutions,
  resultTriples
};