Capstones: from exact computation to a portable result
These capstones connect implemented features into useful results. Run commands from the rix/ repository directory, after the workspace’s bun run prep. Bun and the checked-out dependencies are required. Each source is linked below; read and modify that source instead of copying a second version from this page. Generated method reference chips remain the API reference.
The CLI is the reproducible baseline. Web and Notebook can render portable output values, but live controls require their installed runtime and plugins. A static HTML, SVG, or text result remains useful when a live host is unavailable. No capstone requires RiX-Ed, network access, or a hosted service.
1. Publish an exact report and an interactive companion
Prerequisites: the output guide and publication workflows. Start with the existing publication project, which already contains two sources, local SVG media, named inputs, and a Notebook project.
bun bin/rix.js publish examples/publication-workflow/build.json --out=tmp/capstone-publication
bun bin/rix.js publish examples/publication-workflow/build.json --profile=live --out=tmp/capstone-liveOpen the report’s document.html and compare the small and large named inputs. Inspect manifest.json: source hashes, artifact checksums, and diagnostics make this a repeatable build. The review profile emits HTML, Markdown, Quarto, LaTeX, and an inert bundle. PDF requires pdflatex; an unavailable PDF produces a readable .unavailable.txt artifact rather than an invented successful PDF. The exact n/3 source stays rational even when a target chooses a decimal display.
Open a live document.html, change the input, and compare the recomputed result with its initial static content. Use the review profile when scripts or the live runtime are unavailable. For a bounded failure exercise, add --watch, introduce a syntax error in a source, and confirm the last successful output survives; repair the source to publish the next complete result. Stop watch when finished. See the project README for the native and browser Notebook export path.
2. Report proved roots, ODE bounds, and unfinished work together
Prerequisites: validated box search and ODE tubes. These bundled plugins are loaded by the capstone source.
bun bin/rix.js examples/capstones/certified-exploration.rixThe first nonlinear search processes only five boxes: it reports budgetExhausted, six pending boxes, and six unresolved leaves. Resuming with 26 boxes completes this fixture; replay acceptance is displayed beside the report. A unique box is not necessarily a distinct root: boundary roots may occur in multiple boxes. Preserve pending and unresolved regions in downstream views.
The same report compares exact-rational RK4 steps (approximate) with a checked Picard tube (validated). Rational arithmetic alone does not certify ODE truncation error. The deliberately too-small tube budget returns partial and a covered interval of 0:0; it does not prove nonexistence. Increase budgets only explicitly. This capstone needs no native numerical provider. The Fragment/Table result renders as static HTML or CLI text without a plotting or worker host.
3. Display rounded numbers without replacing exact source
Prerequisites: numeric presentation. The existing numeric-presentation source contains fractions, a reversed interval, a table, a sheet, a control snapshot, and a graphic under one presentation policy.
bun bin/rix.js --out=tmp/capstone-numbers examples/renderers/numeric-presentation.rixOpen numbers.html, then inspect numbers-source.txt. The display of one third is 0.333, while the portable JSON retains the exact rational 1/3. The explicit mixed-fraction override illustrates a local choice inside the report-wide policy. The source interval direction also survives formatting. Markdown, Quarto, and LaTeX are alternative static outputs; the PDF target requires its supported native backend and reports unavailability when it is missing.
The control is deliberately snapshotted, so the saved report does not imply a live connection to a future evaluation. Change the rational source and rebuild to update every format. For positional numeral systems, continue with the radix tutorial and its exact parsing rules.
4. Resolve tensor coordinates before choosing a sheet projection
Prerequisites: tensor sheets and the Sheet guide. Reuse the tested sheet-view source.
bun bin/rix.js examples/rixcel/sheet-views.rixThe cube has named region, measure, and scenario axes. Select the Forecast plane, then resolve South/Cost/Forecast by labels: the result is 11. Compare that coordinate with the alternate row-by-depth view. A projection changes what you see, not the stored coordinates or values. CLI text provides the static alternative to the browser’s address-aware grid; there is no Float conversion.
As a deliberate failure exercise, change Forecast in the .At(...) selector to an unknown label. Lookup rejects it instead of guessing an index. Restore the label before continuing. Large/infinite layouts need an explicit finite window; region and window contracts describe those limits.
5. Cancel concurrent host work and verify cleanup
Prerequisites: basic JavaScript hosting and concurrency safety. Run the host source with Bun:
bun examples/capstones/async-cancellation.mjsThe host registers a read capability explicitly as safe for overlap and cooperative with cancellation. Two admitted branches start before the controller aborts; both release their listeners and execute finally once. The printed record has status: "cancelled", two started IDs, two cleaned IDs, and a fresh static result of 1/2. It uses a deterministic admission gate, not a timer race.
This is a host JavaScript program, not source to paste into a RiX editor. An editor without the registered .pending capability cannot run its inner expression. That is an unavailable-host boundary, not an arithmetic failure. Ordinary exact expressions or saved static output remain available there. Cancellation cannot roll back completed writes or forcibly interrupt synchronous JavaScript. Mark only truly cooperative adapters accordingly; a non-cooperative adapter may remain active until it returns. The example performs no external I/O.
6. Rebuild a spreadsheet from portable source and exchange values
Prerequisites: workbooks and the RiXCel example guide. Reuse both sources:
bun bin/rix.js examples/rixcel/persistence.rix
bun bin/rix.js examples/rixcel/delimited.rixThe first builds a FormulaSheet, exports canonical RiXCel JSON, imports it into a fresh context, and displays recomputed values: 10, 20, 3, and 23. Inspect the printed JSON: formulas are saved source, not trusted serialized closures or cached executable state. The browser Cel app can open the existing budget.rixcel fixture and save edits.
The second imports CSV values, displays a sheet, and exports TSV. Its foreign =SUM(A1:A2) formula remains inert text. Decimal 4.5 is exact rational input; CSV/TSV do not preserve a workbook’s formula graph, history, or complete metadata. Use RiXCel/RiXBook for those semantics. See the format and validation contract for version migration and rejected malformed input. Spreadsheet export capability differs by host: portable JSON and CSV remain available without a native dialog or XLSX host. Do not treat an unavailable save dialog as a failed numerical computation.
Verification and next experiments
bun test tests/cli/capstones.test.js checks the actual linked sources for exact values, static disclosure, interchange, and cleanup. Publication has its existing CLI and host integration tests; the project manifest remains its single source. Experiment by lowering a numerical budget, changing a tensor label, choosing a static publication profile, or changing an exact fraction. Keep the resulting status and host diagnostics visible in the output you share.