Brain Path Query Planner

Trace a brain:// address from raw bytes to its canonical representation

A brain:// address resolves through an explicit nine-stage query planner. This tool makes the derivation concrete and shows that it is not hand-written per modality: enter any canonical address (or pick an example) and the planner parses it, then derives the plan by searching a declarative registry of transforms.

Each transform declares its precondition (the representation it consumes), its effect (what it produces), and a cost. The planner selects the transforms whose effects reach the requested :space/:dtype/:qualifiers and orders them by their preconditions, so step order is derived, not scripted - the same capability-directed assembly a SQL or federated-GraphQL planner runs over a typed catalog.

Where a matching derivative already exists in the cache (e.g. an fMRIPrep output in MNI152), the planner reuses it and skips the upstream steps - a cache hit; toggle reuse cached derivatives to see it. The view below shows the core values the planner computes - the parsed segments, the input files it gathers, the derived operator sequence with each step’s needs/gives/cost, and the registry it was drawn from. See the full Brain Path Specification for the address grammar and the staged planner.

import { parsePath, plan, PRESETS } from "./planner.js"

import { render, errorHTML } from "./view.js"

Enter a brain:// address, or pick one of the examples:

viewof address = html`<input class="bp-input" spellcheck="false" autocomplete="off" value="${PRESETS[0][1]}">`

presetChips = {
  const wrap = html`<div class="bp-presets"></div>`;
  for (const [label, val] of PRESETS) {
    const chip = html`<span class="bp-preset">${label}</span>`;
    chip.onclick = () => {
      viewof address.value = val;
      viewof address.dispatchEvent(new Event("input", { bubbles: true }));
    };
    wrap.append(chip);
  }
  return wrap;
}

viewof useCache = Inputs.toggle({ label: "reuse cached derivatives", value: false })

planView = {
  const root = html`<div class="bp"></div>`;
  const p = parsePath(address);
  root.innerHTML = p.ok ? render(p, plan(p, useCache)) : errorHTML(p.error);
  return root;
}