@tabnas/directive — directive syntax for the tabnas parser

Adds directive syntax to the tabnas parser. A directive is a token sequence (e.g. @name, add<1,2>) that triggers custom parsing behaviour. It is a plugin for the tabnas engine — its only dependency — and layers onto whatever host grammar provides the standard val / list / map / pair rules. TypeScript (canonical) and Go ports share the same API shape and test specs.

Documentation

The four-quadrant TypeScript docs live in doc/: tutorial · how-to guide · reference · concepts. The Go-port docs are in ../go/doc/.

Quickstart

The directive modifies host-grammar rules, so apply it to a Tabnas instance that already has a grammar that provides val / list / map / pair. Here the host is @tabnas/json, which is why the input uses JSON syntax (quoted strings):

const { Tabnas } = require('@tabnas/parser')
const { json } = require('@tabnas/json')
const { Directive } = require('@tabnas/directive')

const j = new Tabnas({ plugins: [json] }).use(Directive, {
  name: 'upper',
  open: '@',
  action: (rule) => (rule.node = String(rule.child.node).toUpperCase()),
})

j.parse('@"x"')              // => 'X'
j.parse('[@"a", @"b", 1]')   // => ['A', 'B', 1]

A minimal host grammar (used by the tests) lives in test/mini-grammar.ts; see the tutorial for a step-by-step walkthrough.

Build and test

The tabnas engine is the only dependency and is consumed from source. From the repository root, make build / make test fetch it into vendor/ and build/test both implementations. The tests bring their own small grammar. See the root README and ../AGENTS.md.

License

MIT — see LICENSE.