@tabnas/debug

Debug / introspection plugin for the tabnas parser.

It makes a grammar visible: a structured model() and a printable describe() return a description of an instance's installed grammar (rules, tokens, plugins), abnf() re-expresses it as ABNF, and trace logs a parse step by step. A dev/test aid — never a runtime dependency.

Install

npm install @tabnas/parser @tabnas/debug

Use

const { Tabnas } = require('@tabnas/parser')
const { Debug } = require('@tabnas/debug')

const tn = new Tabnas({ tag: 'demo' })
tn.use(Debug, { print: false, trace: false })

// describe() is the printable form; model() is the structured form.
typeof tn.debug.describe()        // => 'string'

const m = tn.debug.model()
m.tag                             // => 'demo'
m.config.start                    // => 'val'
m.plugins.map((p) => p.name)      // => ['Debug']
Array.isArray(m.rules)            // => true

Structured output — model()

describe() renders the instance as text; model() returns the same information as a typed, JSON-serialisable object (DebugModel):

| field | what it holds | |---|---| | tag | the instance tag | | tokens | { tin, name, fixed? }[] — the token table | | tokenSets | named token sets → member tins | | rules | each rule's open / close alternates as { seq, push, replace, back, counters, groups, action, cond, modifier } | | graph | per-rule push/replace edges (openPush, openReplace, closePush, closeReplace) | | lexer | the lexer matchers (order, matcher, make) | | config | start rule, finish flag, safe-key, and the per-lexer enable flags | | plugins | the applied plugins (name + options) | | abnf | the live grammar rendered as ABNF text |

The grammar-structure fields round-trip through JSON.stringify.

Documentation

• Tutorial — zero to a working inspection, step by step.
• How-to guide — focused recipes (diff grammars, capture traces, round-trip ABNF).
• Reference — the exact exports, options and types.
• Concepts — how it works and why.

The Go port lives in ../go and tracks this implementation.

License

MIT.