Seam

Seam is a small reasoning language for turning facts and rules into answers and proofs.

Prolog-like syntax. Small core. Inspectable results.

The name comes from the way reasoning joins things together: facts with rules, goals with answers, and answers with proofs.

Install and run

Seam has no runtime npm dependencies and no build step. From a source checkout, run the CLI directly with Node.js 18 or newer:

node bin/seam.js examples/ancestor.pl
node bin/seam.js --proof examples/socrates.pl
node bin/seam.js --warnings test/conformance/warnings/negation/unstratified_mutual.pl
printf 'works(stdin, true) :- eq(ok, ok).\n' | node bin/seam.js -

For one-off local CLI use from the checkout, npm can run the package bin without a manual symlink:

npm exec -- seam --version
npm exec -- seam examples/ancestor.pl

To install the checkout's seam command on your PATH, use npm's package link:

npm link
seam --version

JavaScript API

import { run, Program, Solver } from 'seam';

const result = run(`
materialize(answer, 1).
answer(ok) :- eq(ok, ok).
`);
console.log(result.stdout);

Documentation

• Playground
• Guide
• Language reference
• A Compact Reasoning Workbench

For local browser use, serve the checkout first so the playground can load ES modules and example files:

python3 -m http.server
# then open http://localhost:8000/playground.html

Tests

npm test
npm run test:conformance
npm run conformance:report
# release preparation writes conformance-report.md via the preversion script
npm run test:examples
npm run test:regression