Each side of '..' takes an optional bound marker, defaulting to
start-inclusive, end-exclusive (a..b == a=..<b; a..=b stays the short
end-inclusive spelling):
for 0<..<N (i) { } // 1 .. N-1 (both exclusive)
for 0=..=N (i) { } // 0 .. N (both inclusive)
for 0<..=N (i) { } // 1 .. N
for 0..<N (i) { } // 0 .. N-1 (explicit default)
for xs, 2<.. (x, i) // open range, exclusive start: i = 3, 4, ...
The nine lexemes are single tokens (maximal munch on '<'/'='/'..'), so
expression parsing never sees the leading marker as a comparison; '<',
'<<', '<=', '==', '=>' lex unchanged. An explicit end marker makes the
end expression mandatory; open forms are a.. / a<.. / a=... Works in
runtime, multi-iterable, and inline-for headers.
Regression: examples/0051-basic-for-range-bounds.sx (full matrix, open
start-marked ranges, comptime unroll, runtime bounds, lexer
non-regression); 1152's pinned message generalized.
The for header is now a comma-separated list of iterables with a
positional capture group and no ':' separator:
for xs (x) { } // collection
for 0..n (i) { } // range (end exclusive)
for 1..=5 (a) { } // ..= inclusive end
for xs, 0.. (x, i) { } // index idiom (replaces (x, i))
for xs, ys (x, y) { } // parallel (zip) iteration
for xs (x) => sum += x; // arrow body (full statement)
First-iterable-wins: the first iterable's length drives the loop and
must be bounded; the other positions follow by their own cursors (a
non-first range's end is not consulted or evaluated; a shorter
non-first collection is read past its length on mismatch). The old
single-iterable index capture is replaced by the trailing open range.
Capture/call disambiguation is positional: the paren group immediately
before '{' or '=>' is the capture, every earlier top-level group is a
call. 'for zip(a, b) (x, y)' calls zip; 'for f(n) { }' reads (n) as
the capture and errors with a parenthesize/add-capture hint. The old
':' form errors with a migration hint.
Lowering is unified across forms: one cursor slot per position (ranges
start at their start, collections at 0), all advanced together, the
first position's bound terminating. inline for keeps the single
bounded comptime range.
Migrated the full corpus (examples, library modules, issue repros,
in-source test strings). New coverage: examples/0050 (the full feature
surface) and examples/1149-1155 (seven diagnostic faces). specs.md For
Loop section + grammar rewritten; readme teaser updated.
lowerBreak/lowerContinue emitted a bare br, and the enclosing block's
emitBlockDefers — seeing the terminator — discarded the pending entries
on the assumption a return had already drained them. The breaking
iteration's defers were silently skipped, leaking whatever the cleanup
released.
Lowering.loop_defer_base records the defer-stack height at each loop's
body start (while / for / range-for, saved and restored alongside
break_target); break/continue drain non-onfail entries down to it in
LIFO order via the non-truncating emitLoopExitDefers before branching.
Truncation stays with the lexical block exits — the same entries still
belong to the fall-through path after the branch containing the break.
break/continue outside a loop now diagnose instead of no-op'ing.
Regression: examples/0049-basic-defer-break-continue.sx (for and while,
break and continue, nested-block LIFO drain).
lowerFor's by-value element fetch emitted index_get on the array VALUE;
the emitter realizes that as a whole-array spill to a stack temp + GEP,
per iteration — O(N^2) bytes copied per loop (and pre-0109 it also grew
the stack per iteration, segfaulting a [4096]s64 loop).
When the iterable is an array with addressable storage (and not deref'd
from a pointer, whose identifier alloca holds the pointer rather than
the array), the fetch is now index_gep on the storage + one element
load. Storage-less arrays keep the index_get fallback. The loaded
element remains a copy — mutating the capture does not write back.
Regression: examples/0048-basic-for-array-large.sx (sum over 4096
elements + by-value copy-guard).
lowerVarDecl (unannotated) and lowerDestructureDecl now clear target_type
around the initializer lowering: a declaration without annotation provides
no target, so int/float literals take their spec defaults (s64/f64) instead
of the enclosing function's implicit-return type (x := 0 in a -> s8 fn was
s8; big := 3000000000 in -> s32 silently wrapped to -1294967296).
Regression: examples/0173-types-int-literal-default-s64.sx. The remaining
explicit-annotation wrap (x : s8 = 300) is filed as issue 0112.
Sweep all src/**.zig comments that cite resolved issues (issue NNNN /
fix-NNNN / KB-N): the invariant or mechanism each comment states is
kept; the historical citation is dropped, per the no-conclusion-comments
rule. Pure-history parentheticals are removed outright. References to
the 16 still-open issues (0030, 0041-0056) are untouched, as are test
NAMES carrying regression provenance (matching the sanctioned
"Regression (issue NNNN)" example-header convention).
Also removes the issues/0019-import-non-transitive-c-scope/ fixture dir
— the issue is superseded and its behavior is covered by
examples/0706-modules-import-non-transitive.sx (the .md writeup stays).
issues/0030's repro .sx stays: that issue is an open feature request.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Review follow-up to the ARCH-B split (comment/import hygiene only, no
code changes):
- Section banners that travelled to the wrong file with the B1-B8 cuts
are reworded to describe the section that actually follows (e.g.
stmt.zig's trailing "Expression lowering", expr.zig's "Control flow"
before lowerChainedComparison) or deleted where nothing follows
(4 trailing-at-EOF banners). ffi.zig's facade note no longer claims
the IMP builders "stay here" (they live in lower/objc_class.zig);
protocol.zig's namespace-lookup banner now points at
pack.zig:resolvePackProjection for the orchestrator.
- lower.zig's two lower/expr.zig alias blocks (B8.1 + B8.2 appends)
merged into one.
- 448 unused header decls pruned from the 15 lower/*.zig files (each
had inherited lower.zig's full import block; pruned to fixpoint so
cascading type-extraction consts went too).
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 5-method closure cluster (lowerLambda,
bare-fn trampoline, closure-to-bare-fn adapter, capture collection, env
sizing) into src/ir/lower/closure.zig. 5 aliases on Lowering keep all
call sites unchanged. Method pub-flip: typeAlignBytes.
Resolves the B7.1 flag: CaptureInfo relocates from lower/call.zig to
lower/closure.zig (its domain home, next to collectCaptures); the
Lowering type alias is repointed so external references are unchanged.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 30-method expression cluster (struct/array/
tuple/enum/tagged-enum literals, init blocks, field access on values and
types, optional chains, numeric limits, indexing, slicing, deref, force
unwrap, null coalesce) into src/ir/lower/expr.zig — one contiguous
1,372-line cut. 30 aliases on Lowering keep all call sites unchanged.
Nested StructConstInfo stays on Lowering (field type of
struct_const_map), flipped pub and reached via an alias const, alongside
headNameOfCallee.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 18-method call cluster (lowerCall moved
whole, context diagnostics, foreign-call helper, builtin/function
resolution, generic + runtime-dispatch calls, reflection calls + guards,
default-arg expansion, call param typing) into src/ir/lower/call.zig.
18 fn aliases keep all call sites unchanged.
CaptureInfo (closure-domain type that sat inside the run) travelled and
is re-exposed via a Lowering type alias; candidate to relocate to
lower/closure.zig in B8.3.
Method pub-flips: callResolver, createBareFnTrampoline,
ensureGenericInstanceMethodLowered, fixupMethodReceiver,
getStructTypeName, isStaticTypeArg, lowerPackFnCall, packSpreadRefs,
packVariadicCallArgs, refCapturePointee, resolveParamTypeInSource,
typeSizeBytes, headNameOfCallee.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 23-method defined-class cluster (IMP/property
emission: class/alloc/static/dealloc IMPs, property getters/setters +
ARC runtime decls, defined-state field access, property/method chain
lookup, string-constant globals) plus the single-home
ObjcDefinedStateField type into src/ir/lower/objc_class.zig. 23 aliases
on Lowering keep all call sites (incl. expr_typer.zig facade and
lower/stmt.zig) unchanged. Zero pub-flips — all callees were already
public from earlier steps.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; all 37
.ir snapshots byte-identical, zero expected/ churn.
Verbatim relocation of the 19-method coercion cluster (lowerXX, user
conversions, protocol erasure, default-value construction, zero values,
coerceToType implicit/explicit ladder, C-variadic promotion, call-arg
coercion) plus the nested single-home CoerceMode enum into
src/ir/lower/coerce.zig. 19 aliases on Lowering keep all call sites
unchanged.
Method pub-flip: prependCtxIfNeeded. ParamImplEntry stays a Lowering
nested type (field type of param_impl_map) and is reached via an alias
const.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 13-method protocol cluster (protocol decl
registration, param-protocol instantiation, thunk creation, vtable
globals, protocol-value construction, dispatch emission, impl lookup)
into src/ir/lower/protocol.zig. 13 fn aliases on Lowering keep all call
sites unchanged.
Two pub nested types travelled with the run (ProjectionPosition,
PackProjection) and are re-exposed via Lowering type aliases; they are
pack-domain types and may relocate to lower/pack.zig in B7.2.
Method pub-flips: allocViaContext, callForeign, genericInstanceMethod,
monomorphizeFunction.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 23-method nominal-type cluster (struct/enum/
union/error-set registration, anon-type qualification, nominal-id
stamping, shadow-slot reservation, named-type interning, generic struct
templates + alias registration) plus the nested ShadowTypeDecl union
into src/ir/lower/nominal.zig. 23 aliases on Lowering keep all call
sites unchanged.
Method pub-flip: instantiateGenericStruct. nominal.zig reaches
VisibleStructAuthor and structDeclOfRaw (both relocated to decl.zig in
B4.1) via Lowering-namespace alias consts.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
Verbatim relocation of the 53-method error cluster (error typing,
raise/failable, try/catch/or, inferred-set convergence, trace runtime
hooks) out of the Lowering struct into src/ir/lower/error.zig as free
functions taking *Lowering. Each gets a pub-const alias on Lowering, so
every call site compiles unchanged (decl-alias method resolution).
Pub-flips (callees now referenced cross-file): lowerExpr, coerceToType,
freshBlock, freshBlockWithParams, emitErrorCleanup,
currentBlockHasTerminator, lowerBlock, lowerBlockValue.
Gate: zig build OK; zig build test 426/426; run_examples 541/0; zero
expected/ snapshot churn.
