v0.7.0

Added

• generateScaffoldFiles(source, flags, options): Record<string, string> — new programmatic API that returns a map of filename → content; used by the CLI when --outdir is given (#25)
• InterpreterMixin<TTree, TResult> and WalkerMixin<TTree> exported from the main package — TypeScript mixin interfaces for interpreter and tree-walker traversal patterns

Fixed

• --transformer json --facade --pipeline now produces three separate scaffold files ({base}-transformer.ts, {base}-pipeline.ts, {base}-facade.ts) so the facade is a genuine module boundary; consumers import only from the facade (#25)

Changed

• --output <file> renamed to --outdir <dir> — the flag now accepts a directory; artifact filenames are derived from the parser base name (e.g. date-facade.ts, date-transformer.ts) (#25)
• --traversal alone now adds mixin stubs directly to the generated parser file (can be re-generated freely) rather than producing a separate scaffold file. Using --traversal together with --facade, --pipeline, or --transformer still produces a scaffold file

v0.6.0

Added

• ScannerlessRDParser — concrete character-by-character parser, extracted from RDParser. Replaces direct RDParser extension for scannerless grammars.
• TokenRDParser and TokenStream — new parser variant that operates over a pre-tokenised token stream rather than raw bytes.
• withObservable(Base) — mixin function that adds ParseObserver support to any RDParser subclass (e.g. withObservable(TokenRDParser)).
• --scaffold now accepts a --lexer span flag, emitting a span-tokeniser and classifier pipeline scaffold.

Changed

• RDParser is now an abstract base class. It no longer contains character-reading methods (peek, advance, matchChar, etc.) — those live on ScannerlessRDParser. Existing parsers that extended RDParser directly must switch to ScannerlessRDParser.
• ObservableRDParser now extends ScannerlessRDParser instead of RDParser.
• ScaffoldFlags type replaced the previous scaffold option shape with orthogonal flags (traversal, transformer, facade, pipeline, lexer). Invalid combinations (e.g. --traversal interpreter --pipeline without --facade) now throw at codegen time.
• Generated parser scaffolds reference ScannerlessRDParser instead of RDParser (except --lexer span scaffolds, which use TokenRDParser).

v0.5.0

Added

• Transformer<Union, T> type and transform() function exported from the main package — like Visitor but with required keys, giving a compile-time exhaustiveness guarantee that every kind in the union has a handler.
• JSONAST discriminated union type (string | number | boolean | null | array | object), plus toJSONAST and fromJSONAST helpers, exported from the main package — a typed representation of JSON values for use as a Transformer target when translating a DSL to JSON.
• --scaffold transformer — emits an exhaustive Transformer<ParseTree, T> object with one stub per grammar rule, plus a convenience transform<Base>(input) wrapper.
• --scaffold json-transformer — emits two transformer stubs (<base>ToJSON: Transformer<ParseTree, JSONAST> and jsonTo<Base>: Transformer<JSONAST, string>) and round-trip helpers (<base>ToJSONString / jsonStringTo<Base>) for two-way translation between the grammar's format and JSON.

v0.4.0

Added

• --scaffold now accepts a composable --inner <strategy> option that specifies the traversal strategy embedded inside facade and pipeline wrappers. Eight combinations are now available: two standalone (interpreter, tree-walker) and six composable (facade --inner interpreter, facade --inner tree-walker, facade --inner pipeline:interpreter, facade --inner pipeline:tree-walker, pipeline --inner interpreter, pipeline --inner tree-walker). facade and pipeline require --inner; interpreter and tree-walker forbid it.
• ScaffoldInner type ('interpreter' | 'tree-walker' | 'pipeline:interpreter' | 'pipeline:tree-walker') exported from @configuredthings/rdp.js/generator for use with the programmatic generateScaffold API.

Changed

• childNodes helper is now always emitted alongside the generated parser; the --walker flag has been removed. There is no longer any reason to pass a separate flag to get tree-walking support.
• --scaffold evaluator renamed to --scaffold interpreter to align with standard language-implementation terminology.
• --scaffold walker renamed to --scaffold tree-walker; --inner walker renamed to --inner tree-walker; --inner pipeline:walker renamed to --inner pipeline:tree-walker.

Removed

• --walker flag removed from rdp-gen <grammar> documentation and generated output. childNodes is unconditionally emitted; --walker is silently accepted and ignored for backwards compatibility.

v0.3.0

Added

• src/grammars/arith.ebnf — canonical arithmetic expression grammar (with whitespace handling, operator precedence, and parenthesised sub-expressions) used throughout worked examples; exported as arithEBNF from @configuredthings/rdp.js/grammars
• src/examples/arith/ — complete worked example: generated ArithParser (with childNodes walker), all four scaffold files (arith-evaluator, arith-facade, arith-pipeline, arith-walker), grammar AST export, and TypeDoc entry point. Documented as the ArithExample API module
• npm run generate:examples — regenerates all files in src/examples/arith/ from arith.ebnf via the built CLI; follows the same pattern as generate:meta
• src/__testUtils__/generator-runtime.ts — shared test helpers (transpile, compileAndImport, importScaffold, nav) extracted from duplicate definitions across generator test files
• Evaluator scaffold now emits // node.field: Type inline comments in each stub function body, showing the exact node shape without requiring users to cross-reference the generated types file
• New guide page "Worked Example: Arithmetic Parser" covering the full lifecycle from grammar to generated parser to all four scaffold patterns; linked from README, CLI reference, and Using the Parse Tree
• rdp-gen init now emits a starter src/<ClassName>.ts alongside package.json and tsconfig.json, scaffolding the private-constructor / static-parse boilerplate so a new project compiles immediately (#13)
• rdp-gen init --observable variant extends ObservableRDParser instead of RDParser; the starter includes notifyEnter/notifyExit call sites and accepts an optional ParseObserver parameter in static parse()
• rdp-gen generate --scaffold <pattern> emits a one-time starter file for a chosen usage pattern (not regenerated; edit freely). Four patterns are available: evaluator (a typed function per grammar rule), facade (domain error class, public entry point, transform stub), pipeline (parse / validate / transform stage stubs), walker (a walk() utility built on childNodes) (#17)
• rdp-gen generate --walker appends a childNodes(node: ParseTree): ParseTree[] helper to the generated parser file, returning the direct ParseTree children of any node — useful for tree walkers, linters, and formatters (#17)
• Visitor<Union, T> type and visit() function exported from the main package — dispatch a parse-tree node to the matching handler in a visitor map without writing explicit switch statements; use Required<Visitor<ParseTree, T>> to enforce exhaustive handling (#17)

Changed

• npm run diagrams replaced by docs-site/scripts/render-diagrams.sh — auto-discovers all .puml files rather than requiring each to be listed explicitly
• Architecture diagram restructured so grammar.ebnf → Toolchain (build-time) → Your parsers reads left-to-right; skinparam linetype ortho eliminates curved arc arrows throughout
• cli.mdx EBNF grammar examples and RailroadDiagram component now import arithEBNF from @configuredthings/rdp.js/grammars rather than inlining the grammar text
• Internal cross-links added throughout the guide (LL(1) → Concepts, --observable → Debugging, TypeDoc API links for key types and functions)
• CI: pr-checks.yml and docs.yml now verify that committed files in src/examples/ match npm run generate:examples output, failing with a diff if they drift

Removed

• commander dependency removed from the CLI — replaced with Node's built-in util.parseArgs. Turns out "zero dependencies" is easier to maintain when there actually are zero dependencies.

Changed

• rdp-gen init simplified package.json scripts: the scaffolded project now has a single build: tsc script rather than a grammar-generation step, reflecting that init targets hand-written parsers
• Generated parse-tree node types now use named fields for non-terminal references instead of positional item0, item1, … names. A field referencing rule Year is now typed as year: YearNode; terminals (string literals, char values) keep itemn names. When the same non-terminal appears more than once in a rule body all occurrences are suffixed (year0, year1, …). This is a breaking change for any code that accesses generated node fields by positional name (#15)
• Generated parser methods now use per-method, per-hint variable counters instead of a single global counter. Internal variable and label names (_pos0, found_alt0, …) reset to index 0 at the start of each method, producing cleaner and more readable generated output (#15)

v0.2.0

Added

• Added integration tests that type-check generated parser output using the TypeScript compiler API (ts.createProgram) under strict: true and noUncheckedIndexedAccess, covering terminals, sequences, alternations, optional/repetition constructs, non-terminal references, observable mode, and ABNF grammars.
• Dependabot configuration to track npm dependencies (root package only) and GitHub Actions versions

Changed

• SECURITY.md — added Scope section clarifying that only library runtime dependencies are in scope; docs-site build-toolchain vulnerabilities are explicitly out of scope

Fixed

• rdp-gen now emits (A | B | C)[] instead of A | B | C[] when a repetition (*, +, or m*n) repeats a mixed-type alternation. The previous output was parsed by TypeScript as A | B | (C[]), causing type errors under strict: true. (#3)

v0.1.0

Added

• RDParser — base class for writing recursive descent parsers in TypeScript, with buffer management and position tracking
• ObservableRDParser — extends RDParser with opt-in parse tracing via an attached ParseObserver
• TraceObserver and DebugObserver — built-in observer implementations for collecting and printing parse traces
• rdp-gen CLI — reads an ISO 14977 EBNF or RFC 5234 ABNF grammar file and emits a fully typed TypeScript parser class
• GrammarInterpreter — runtime interpreter that executes a grammar directly from its AST without a code-generation step
• EBNFParser and ABNFParser — parse EBNF and ABNF grammar source into a GrammarAST
• generateParser — programmatic API for generating parser source from a grammar string
• Dual ESM/CJS package with full TypeScript declarations
• Bootstrapping meta-grammars: EBNF and ABNF formats each described in both EBNF and ABNF (src/grammars/)
• Left-recursion detection at grammar compilation time