# V3 step 6.1 — built-ins for self-hosting (done 2026-09-22)

Closes the first gap measured against the compiler's own sources
(they use `INC`/`DEC`/`CHR`/`ORD`/`VAL`/`HIGH`/`LEN`/`SIZE`/`TSIZE`).
Suite 99/99. LL(1)-clean, zero gm2 warnings.

## What was missing

A scan of `SymTab.mod`/`QbeGen.mod` showed `CHR`, `ORD`, `VAL`,
`INC`, `DEC`, `ABS` were **not** implemented (`HIGH`/`LEN`/`SIZE`/
`TSIZE`/`NEW`/`DISPOSE` already were). Without these, the compiler
cannot compile itself.

## Added (grammar `Fact` / `Statement`)

- **`CHR(x)`** → `CHAR` (x integer-family, else 211).
- **`ORD(x)`** → `INTEGER` (x char/bool/enum/int-family, else 211).
- **`VAL(T, x)`** → value of type `T`: allowed when source and
  target share a storage class (int/char/bool/enum → `w`,
  pointers/ADDRESS → `l`, REAL → `d`); the operand passes through
  unchanged. Cross-class reinterprets are 230 (VAL is a cast, not a
  conversion). Covers the compiler's `VAL(INTEGER|CARDINAL, …)`.
- **`ABS(x)`** → `|x|` for integer or REAL; new `QbeGen.AbsQ`
  (compare + negate-select branch).
- **`INC(v [,step])` / `DEC(v [,step])`** as statements over an
  integer designator (var, VAR param, or indexed/field element);
  default step 1.

## Test

`t_builtins` → 42: `ORD('A')`, `INC`/`DEC` with and without a step,
`CHR` back to `'>'`, `ABS(-3.5)`, `VAL(INTEGER, 0)` /
`VAL(CARDINAL, 1)`.

## Next self-hosting gaps

- The syslib port: rewrite `FileIO` on `SysIO`/`Storage`, ban the
  gm2-only imports (`Environment`, `FileSysOp`, `SysClock`,
  `ProgramArgs`, `TextIO`, `RawIO`, `WholeIO`, `IOChan`).
- `LONGINT`/`LONGCARD` true 64-bit values (currently aliases to
  `w`) — the compiler uses them for file sizes/positions.
- `VAL`/`CAST` across storage classes; `FLOAT`/`TRUNC`; `CAP`.