M2compiler-V3/docs/summary_two-phase-slice12.md

Two-phase refactor — slice 12 (nested modules)

Branch ast-stage-c. Suite 178/178; self-hosting fixpoint OK (3,034,200 bytes; slice 11 was 3,032,308).

What landed

NestedModule now builds an NkUnit(name, decls, body, imports) using its own local import accumulator (nImp/nImpTail), and sets astDecl to that node — so the enclosing DeclSeq records the nested module as a declaration. A local accumulator keeps the enclosing unit's imports (astImp) intact.

Verified (temporary AST.Dump, then removed)

MODULE nestdump;
VAR x : INTEGER;
MODULE Inner;
  VAR y : INTEGER;
BEGIN y := 5 END Inner;
BEGIN x := 1 END nestdump.

gave the outer NkUnit(nestdump, decls=[NkVarDecl x, NkUnit(Inner, decls=[NkVarDecl y], body=[y:=5])], body=[x:=1]).

Still not covered

• CLASS / CLASS IMPLEMENTATION items. Note: the compiler's own sources contain no actual class declarations (only the word in comments and the scanner's keyword table), so this is not needed for self-hosting validation — it is a user-facing OOP feature and a sizeable slice of its own.
• Lower + .ssa byte-compare.
• MaxChild cap on CASE arms / WITH designators / call actuals.

Next

CLASS (if desired) or the Lower walk.