Tree-sitter Grammar for TTCN-3

A tree-sitter grammar for TTCN-3 (Testing and Test Control Notation, ETSI ES 201 873-1).

Status

v0.2.1 — parses real-world 3GPP conformance TTCN-3 code at 100% clean (385/385 files in the NR5GC corpus have 0 errors; 0 ERROR nodes total). Up from v0.2.0's 99.7% / 2 errors. Parser is generated without warnings; 159/159 corpus tests pass.

The v0.2.1 jump closed the last grammar gap left open by v0.2.0:

• Trailing ifpresent matching attribute on template assignment RHS — added an optional extra_matching_attributes field to the template rule so template T x := f(args) ifpresent; parses (spec rule 95 ExtraMatchingAttributes). One new conflict declared: [$.any_value] — the existing any_value: $ => seq('?', optional($.length_attribute)) rule overlapped with the new length_attribute suffix on expressions; GLR resolves in favor of the any_value interpretation.

159/159 corpus tests pass (158 from v0.2.0 + 1 new V1.17 test for the template RHS ifpresent pattern).

Earlier milestones

• v0.2.0 — 99.7% clean (384/385, 2 errors). Closed four grammar gaps on top of v0.1.1: -> value v_X redirect inside check(receive(...)), array type with explicit size, inline union/record/set blocks in type record body, complement(...) with multiple args, and formal- parameter default with trailing ifpresent.
• v0.1.1 — 97.7% clean (376/385, 18 errors). Diagnosed the ident '<' shift-reduce conflict on type_instantiation_expression vs. rel_expression: the static prec(PREC.primary) on type instantiation was committing the LR(1) table to the generics path on every ref < num pattern. Resolved by dropping the static precedence, switching to prec.dynamic(-1, ...), and declaring the table-level conflicts ([$.reference, $.type_instantiation_expression] and [$.name, $.type_instantiation_expression]) so Tree-sitter's GLR engine forks at runtime. Zero regressions; parser size +270 bytes.
• v0.1.0 — 83.6% clean (322/385, 204 errors).

Language support

• Module definitions, group definitions
• Function / altstep / testcase / configuration / control
• Behavioral types: component, port, timer, signature, class
• Type system: record / set / union / enumerated / map / array / port / signature
• Declarations: var / const / timer / port / template / modulepar
• Templates: restrictions, modifiers, parameterized, modifies, all matching symbols (? / * / ifpresent / range / complement / subset / superset / permutation / decmatch / pattern / length)
• Expressions: full precedence chain (or → and → not → rel → shift → bitwise → add → mul → unary → primary)
• Statements: if / for / while / select / alt / interleave / do-while / label / goto / break / continue / return
• Communication: port dot-ops, config ops, component lifetime, activate/default, timer ops
• Test operations: testcase.stop, execute, test-component call
• Editor support: syntax highlighting, scope tracking, code navigation, injections
• Tests for the optional external scanner (not used — grammar is pure grammar.js)

Usage

Build the C library

make            # produces libtree-sitter-ttcn3.{a,so} + tree-sitter-ttcn3.pc
make install    # installs to /usr/local

Run tests

npm test                       # regenerates parser + runs corpus tests
npx tree-sitter test           # runs corpus tests only
npx tree-sitter generate       # regenerates parser only

Parse a TTCN-3 file

npx tree-sitter parse path/to/file.ttcn

Language bindings

Six bindings are shipped in-tree:

Language	Build
Node	npm install
Python	pip install .
Rust	cargo build
Go	go build (after tree-sitter generate)
C	make
Swift	swift build (after tree-sitter generate)

Project layout

.
├── grammar.js               # The grammar (hand-written)
├── src/                     # Generated artifacts (committed, do not edit)
├── test/corpus/             # TTCN-3 grammar tests (158 tests)
├── queries/                 # Editor support (highlights, locals, tags, injections)
├── bindings/                # 6 language bindings
└── docs/                    # Development plan, gap analysis

Documentation

• Development plan — task breakdown, status, effort budget
• Gap analysis — feature inventory vs spec coverage

Contributing

See CONTRIBUTING.md. The grammar is a single hand-written grammar.js; parser artifacts (src/parser.c, src/grammar.json, src/node-types.json) are generated and committed.

Note: This project is in maintenance mode. Change requests are welcome, but active development is not scheduled.