Stocks

Package: opt-in. createStocksPackage({ fetchQuote }) is not among the built-ins createEngine() registers; you construct it with your own fetching function and add it to the engine’s packages (see choosing packages).

The engine holds no market-data key. Prices come from a function you supply, so the provider, and whatever key it needs, stays yours.

import { createStocksPackage } from "solve-engine/packages";

const stocks = createStocksPackage({
  fetchQuote: async (ticker, signal) => {
    const res = await fetch(`https://example.com/quote/${ticker}`, { signal });
    return res.json();
  },
});

With that in place, a ticker in a stock(...) call resolves to its price:

Expression	Result
stock(AAPL)	the current price
stock(AAPL) * 100	the price of a hundred shares
stock(AAPL) on April 12, 2005	the closing price on that day
stock(AAPL) close on 2005-04-12	the same, with the field named
stock(AAPL) volume on 2005-04-12	the volume traded that day

A dated lookup reads from a second function, fetchHistoricalQuote, supplied the same way. The stock(TICKER) call is the form the engine recognises; reading a bare ticker (AAPL on its own) is a further opt-in, off by default, so an ordinary word is never mistaken for a symbol.

Without a fetchQuote, stock(AAPL) returns a clearly named STOCKS_NOT_CONFIGURED error rather than a fabricated or zero price. A live price reaches the network, so its first result is a pending value and the real answer arrives once the request returns. A quote left on screen can also refresh on its own, without a keystroke: pass refetchIntervalMs and enable background refresh. See async and live data for how a host waits on the result and drives that schedule.

The results depend on the live provider, so they are shown here rather than asserted.