feat(grammar)!: require semicolons on microflow and nanoflow statements

[ako]

BREAKING CHANGE. Every statement inside a microflow or nanoflow body must now end with ;, including block terminators (end if;, end loop;, end while;, end case;). Omitting one is a parse error where it was previously accepted.

Why

Semicolons were optional on all 54 body-statement alternatives, which leaves statement boundaries ambiguous whenever a keyword can both continue a statement and start one. The concrete case that surfaced it — adding a trailing commit modifier to create/change for mendixlabs#779:

$a = create Mod.E
commit $b;

ANTLR is greedy, so commit binds to the create rather than starting a commit activity. Diagnosing that per keyword does not scale; requiring the terminator removes the class.

Scope

Deliberately limited to microflow/nanoflow bodies. The document terminator (end;, or end followed by /) stays optional, as it is for pages and every other document type.

That boundary is measured, not assumed. Tightening the top-level statement rule instead:

Change	pass / fail	newly broken
baseline	234 / 39	—
microflow-body ; mandatory (this PR)	234 / 39	2
top-level ; mandatory	146 / 127	88
top-level: require ; or /	157 / 116	77

Of those 77, 75 are page / snippet / layout and 0 are domain models. Block-bodied documents have never required a terminator, and three styles coexist in the corpus — 168 definitions ending on a bare }, 56 on };, 62 on } then /. Tightening that is a separate and much larger decision, worth an ADR if it is wanted at all.

Migration

2 of 273 example files needed fixing, all genuine omissions:

  end loop        →  end loop;             ledger-52-break-in-conditional
  log trace …''   →  log trace …'';        02-microflow-examples (×3)
  raise error     →  raise error;          inside an on-error block

Example corpus is back at exact baseline parity — 234 pass / 39 fail, 0 regressions.

Test fixtures embedding MDL needed the same treatment: enginecompare (8 — RETURN true END → RETURN true; END, end loop END → end loop; END), validate_microflow_hints_test.go (8), visitor_test.go (1).

Docs needed no migration — verified, not assumed

I extracted every self-contained create microflow/nanoflow … end block from .claude/skills/, docs-site/src/ and the quick reference, then parse-checked all of them against both the old and the new binary. Identical results, 0 regressions. (An earlier line-based scan flagged 39 doc lines; those were false positives — multi-line statements whose semicolon sits on a continuation line.)

The rule is now documented in write-microflows.md, write-nanoflows.md and MDL_QUICK_REFERENCE.md, each stating explicitly that the definition terminator remains optional — otherwise agents will "helpfully" add ; after end too.

Diagnostics

Already precise for this case, so no error-reporting work was needed:

line 143:2 missing ';' at 'return'

🤖 Generated with Claude Code

https://claude.ai/code/session_012XR649rKk68z6gBpngu6MA

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