[P7] OpenSCENARIO DSL Frontend - tracking

[JArmandoAnaya]

[P7] OpenSCENARIO DSL Frontend — tracking

Tracking issue for pillar P7. See docs/roadmap/roadmap.md.

Objective

A grammar-based parser (ANTLR4 C++ runtime, BSD), AST, symbol resolution and type system for ASAM OpenSCENARIO DSL 2.x, able to load and check the finalized standard library and concrete scenario files with actionable diagnostics — shipping scena-check for DSL files (DSL §7; coverage: docs/roadmap/coverage/osc-dsl-coverage.md). Constraint (keep) and coverage constructs are parsed and checked but not solved. Out of scope: external-method binding to host code (diagnosed as unsupported when invoked), constraint solving (F4), any execution (P8).

Sprints

• p7-s1 — DSL grammar & lexer (ANTLR4) ([p7-s1] DSL grammar & lexer (ANTLR4) #39)
• p7-s2 — Parser & AST ([p7-s2] Parser & AST #40)
• p7-s3 — Symbols & type system ([p7-s3] Symbols & type system #41)
• p7-s4 — Expressions, constraints & coverage (check-only) ([p7-s4] Expressions, constraints & coverage (check-only) #42)
• p7-s5 — Standard library checking & scena-check ([p7-s5] Standard library checking & scena-check #43)

Pillar exit criteria

• The DSL standard library type-checks with zero errors
• Spec-annex-derived example files parse and check with precise diagnostics (section-number citations — the DSL spec defines no rule IDs)
• scena-check exits nonzero with actionable messages on seeded error corpora

---

Status (2026-08-02 continuous-improvement audit): all P7 sprints merged; the standard library type-checks clean; scena-check corpus green. Residual: #110 (overloaded enum literals not resolved by expected type, §7.3.3) means a scenario copied verbatim from the spec (at: start) fails to check — the "spec-annex-derived examples check" exit criterion is not honestly met until it lands.

[JArmandoAnaya]

P7 — OpenSCENARIO DSL Frontend: complete

All five sprints are merged and their issues closed. Scena parses, resolves and
type-checks ASAM OpenSCENARIO DSL 2.x against the full bundled §8 standard
library, and reports what it finds through four surfaces.

Sprint	Issue	PR	Merged as
p7-s1 — grammar & lexer	#39	#92	3e80312
p7-s2 — parser & AST	#40	#93	b3382ac
p7-s3 — symbols & type system	#41	#94	e17ebc2
p7-s4 — expressions, constraints & coverage	#42	#95	7bc8673
p7-s5 — standard library & scena-check	#43	#96–#99, #101–#105	01263bc → 84f993f

p7-s5 landed in nine slices, because §8 is printed as ~160 parameter tables and
each chapter needed 800–2000 lines of specification read before a line of DSL
could be written:

Slice	Content	PR
43a	import mechanism (§7.7.5) + osc.standard.types	#96
43b	§8.7 physical-object actors	#97
43c	§8.12 road abstraction	#98
43d	§8.8.1 action hierarchy + §8.10/§8.11 environment	#99
43e + 43h	§8.12.2 the map actor + §8.15 traffic lights	#101
43f	§8.8.2–§8.8.4 movement actions	#102
43g	§8.9 movement modifiers	#103
43i-1	the scena-check CLI	#104
43i-2	C ABI scn_check_dsl_* + Python check_dsl_*	#105

Exit criteria

• Standard library checks clean. The whole of §8 loads with zero
  diagnostics, pinned declaration by declaration in dsl_stdlib_test.cpp.
• scena-check corpus green. 18 subprocess tests over the CLI, with
  exit codes split along the Status model's line: 0 ok, 2 usage, 3 the
  source did not check, 4 the input could not be read.
• Bindings updated in the same PR. feat(dsl): C ABI and Python DSL checking, closing p7-s5 (#43) #105 carries the C ABI, the Python
  bindings, an example run in CI and the parity audit together, as
  CONTRIBUTING.md requires. The audit now covers the frontend entry
  points, not just Engine methods, so a future frontend function cannot
  reach one surface and quietly miss the others.
• CI green on every platform for all nine PRs — macOS, Linux, Windows,
  ASan+UBSan, clang-format, the determinism trace and the golden suite.

Deliberate exclusions, each recorded

• Constraint solving is post-v0.0.1 (ADR-0004). Constraints that do not fold
  to fixed values are accepted with an UnsupportedFeature warning rather than
  approximated — reporting beats guessing where determinism is at stake. Same
  treatment for coverage collection, sample() and every.
• §8.7.26 (traffic-participant groups) is explicitly non-normative and is
  excluded.
• The library is authored from the normative §8 text, not copied from any
  file (ADR-0029), and embedded as chunked raw literals — MSVC caps a single
  string literal at 16380 bytes, and this keeps the library independent of any
  install prefix.
• The standard's printed conversion factors are carried verbatim. §8.14.1.3
  prints the kph factor as 0.277777778, so 36kph == 10mps is false.
  Conformance beats tidiness; pinned by test.
• DSL diagnostics cite section numbers and leave rule_id empty, because
  the DSL standard defines no asam.net: rule identifiers. Asserted, not
  assumed.

Three defects found in ASAM OpenSCENARIO DSL 2.2.0

Each resolved by asking which surface the rest of the chapter corroborates, and
each pinned by a test so the resolution stays visible:

1. §8.15.4.2.1 prints the wrong receiver — the group's state_equal
   prototype says extend traffic_light: while the heading, the prose and
   Table 319 all say traffic_light_group.
2. Table 337 names the wrong parameter — set_group_bulb_state's first
   parameter is typed traffic_light while its own description says "group".
   The parameter table is what a conforming scenario is written against, so it
   is carried verbatim and the inconsistency recorded.
3. §8.8 and §8.9 collide with each other — §8.8 declares actions
   movable_object.change_speed, movable_object.keep_speed and
   vehicle.change_lane; §8.9 declares modifiers of exactly those names for
   exactly those actors, and a qualified behavior name identifies one
   declaration. Those three take §7.3.12.3's unassociated form, the only
   spelling that exists and does not collide.

Known gap carried into P8

#100 — an actor-associated modifier cannot be applied, in either position
§7.3.12.4.1 defines. The declarations are well-formed and checked; the
application side is not. It predates these chapters and p8-s3 (#46) depends on
it, so it is the next thing to land.

ADRs: 0027 (hand-written lexer/parser), 0028 (the type model), 0029 (the bundled
library). Leaving this issue open per repo convention.