next: ai part 3

2026-07-23 17:08:10 -07:00 · 2026-07-22 16:50:32 +02:00
parent 52e4db5ea6
commit f0871d895a
29 changed files with 3207 additions and 143 deletions
@@ -0,0 +1,167 @@
+const DEFINITION = /\b([A-Za-z][A-Za-z0-9_]*)\s*=\s*(.+)$/;
+const IDENTIFIER = /^[A-Za-z][A-Za-z0-9_]*$/;
+
+/** @param {string} value */
+function cleanExpression(value) {
+  return value
+    .replace(/[`.;]+$/g, "")
+    .replace(/[·×]/g, "*")
+    .replace(/([A-Za-z][A-Za-z0-9_]*)²/g, "$1^2")
+    .replace(/\s+/g, "")
+    .replace(/^sum/i, "Σ");
+}
+
+/** @param {string} value @param {string} operator */
+function splitTopLevel(value, operator) {
+  let depth = 0;
+
+  for (let index = 0; index < value.length; index += 1) {
+    const character = value[index];
+    if (character === "(") depth += 1;
+    else if (character === ")") depth -= 1;
+    else if (character === operator && depth === 0) {
+      return [value.slice(0, index), value.slice(index + 1)];
+    }
+  }
+
+  return undefined;
+}
+
+/** @param {string} value */
+function unwrapSum(value) {
+  return value.match(/^Σ\((.+)\)$/)?.[1];
+}
+
+/** @param {string} value */
+function factorMap(value) {
+  /** @type {Map<string, number>} */
+  const factors = new Map();
+
+  for (const rawFactor of value.split("*")) {
+    const match = rawFactor.match(/^([A-Za-z][A-Za-z0-9_]*)(?:\^(\d+))?$/);
+    if (!match) return undefined;
+
+    const [, name, rawPower] = match;
+    const power = Number(rawPower ?? 1);
+    if (!IDENTIFIER.test(name) || power < 1) return undefined;
+    factors.set(name, (factors.get(name) ?? 0) + power);
+  }
+
+  return factors;
+}
+
+/** @param {Map<string, number>} total @param {Map<string, number>} part */
+function subtractFactors(total, part) {
+  const result = new Map(total);
+
+  for (const [name, power] of part) {
+    const remaining = (result.get(name) ?? 0) - power;
+    if (remaining < 0) return undefined;
+    if (remaining === 0) result.delete(name);
+    else result.set(name, remaining);
+  }
+
+  return result;
+}
+
+/** @param {Map<string, number>} factors */
+function factorsText(factors) {
+  return [...factors]
+    .flatMap(([name, power]) => Array.from({ length: power }, () => name))
+    .join(" × ");
+}
+
+/** @param {string} value */
+function title(value) {
+  const words = value.replace(/_/g, " ");
+  return words[0].toUpperCase() + words.slice(1);
+}
+
+/** @param {string} value */
+function plural(value) {
+  if (value.includes(" × ")) return `${value} values`;
+  return value.endsWith("s") ? value : `${value}s`;
+}
+
+/** @param {string} metric @param {string} rawExpression */
+function deriveFormula(metric, rawExpression) {
+  const expression = cleanExpression(rawExpression);
+  const division = splitTopLevel(expression, "/");
+  if (!division) return undefined;
+
+  const numeratorExpression = unwrapSum(division[0]);
+  const denominatorExpression = unwrapSum(division[1]);
+  if (!numeratorExpression || !denominatorExpression) return undefined;
+
+  const numerator = factorMap(numeratorExpression);
+  const weight = factorMap(denominatorExpression);
+  if (!numerator || !weight) return undefined;
+
+  const value = subtractFactors(numerator, weight);
+  if (!value?.size) return undefined;
+
+  const otherWeight = subtractFactors(weight, value);
+  return {
+    metric,
+    formula: `${metric} = ${rawExpression.trim()}`,
+    value: factorsText(value),
+    weight: factorsText(weight),
+    otherWeight: otherWeight ? factorsText(otherWeight) : "",
+  };
+}
+
+/** @param {{ path: string, text: string }} file */
+function formulasInFile(file) {
+  return file.text.split("\n").flatMap((line, index) => {
+    const comment = line.replace(/^\s*(?:\/\/\/?|#)\s?/, "").trim();
+    const definition = comment.match(DEFINITION);
+    if (!definition) return [];
+
+    const fact = deriveFormula(definition[1], definition[2]);
+    return fact ? [{ ...fact, path: file.path, line: index + 1 }] : [];
+  });
+}
+
+/** @param {string} question @param {string} metric */
+function questionScore(question, metric) {
+  const normalizedQuestion = question.toLowerCase().replace(/[_-]+/g, " ");
+  const normalizedMetric = metric.toLowerCase().replace(/_/g, " ");
+  if (normalizedQuestion.includes(normalizedMetric)) return normalizedMetric.length + 10;
+
+  const words = normalizedMetric.split(" ");
+  return words.every((word) => normalizedQuestion.includes(word)) ? words.length : 0;
+}
+
+/** @param {{ path: string, text: string }[]} files */
+export function createFormulaIndex(files) {
+  return files.flatMap(formulasInFile);
+}
+
+/**
+ * @param {string} question
+ * @param {ReturnType<typeof createFormulaIndex>} formulas
+ */
+export function explainFormula(question, formulas) {
+  const fact = formulas
+    .map((candidate) => ({
+      candidate,
+      score: questionScore(question, candidate.metric),
+    }))
+    .filter(({ score }) => score > 0)
+    .sort((a, b) => b.score - a.score)[0]?.candidate;
+  if (!fact) return undefined;
+
+  const metric = title(fact.metric);
+  const values = plural(fact.value);
+  const consequence = fact.otherWeight
+    ? ` For the same ${fact.otherWeight}, higher ${values} have more influence on the result.`
+    : "";
+
+  return {
+    answer:
+      `${metric} is a weighted average of ${values}. ` +
+      `Each ${fact.value} is weighted by \`${fact.weight}\`.${consequence}\n\n` +
+      `Source: \`${fact.path}:${fact.line}\``,
+    fact,
+  };
+}