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# Arrays
Part of the [subsystem notes](../SUBSYSTEMS.md). Invariants:
[`CONVENTIONS.md`](../CONVENTIONS.md); known bugs: [`PITFALLS.md`](../PITFALLS.md).
**Arrays** (`ArrayHandler`): allocation/indexing live in `ArrayHandler.cc`,
parameter binding/arguments in `ArrayParameters.cc`, and output in `ArrayOutput.cc`.
## Storage and metadata
- A DECLAREd array is one malloc'd flat buffer (memset to zero), row-major, any rank,
any bounds.
- Bounds and multipliers are *SSA values* cached in `ArrayMetadata`.
- `ArrayTable` is scoped per function (`exchangeTable`, driven from CodeGen's
`FunctionDefAST` branch, mirroring the Symbols discipline).
- Element sizes are `sizeof` constants (`ElementSizeC`), never host-side numbers.
## Indexing pipeline
Every access goes through `emitCheckedIndices` (validates the index count for the
caller's semantics, then per-dimension coerce + `emitIndexCheck`) →
`computeFlatIndex` → `loadElement` (load + the typed value load).
The public `emitElementAddress` exposes the same checked pipeline as an address for the
lvalue layer (`Form[i].YearGroup`, `^arr[i]`) — never hand-roll indexing or element
loads.
## Array parameters
- `bindArrayParameter` rebuilds callee-side metadata from the flattened
`ptr + 2R bounds` ABI (BYVAL = allocated buffer copy with independent STRING-bearing
elements).
- `emitArrayArgument` validates and pushes the caller side.
## Array output
`OUTPUT arr` (and partially-indexed accesses) is intercepted by
`ArrayHandler::tryEmitArrayOutput` — the first branch for each expression in an OUTPUT
list, emitting nested print loops (element kinds that are not outputtable, i.e.
records/pointers, are a compile error there). Arrays keep their per-element newlines and
dispatch continues with the next expression; a final array requires no extra newline.
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